74 - Surgical Planning in Orthognathic Surgery and Outcome Stability

Prévia do material em texto

1048
Surgical Planning in Orthognathic Surgery 
and Outcome Stability
Larry M. Wolford, Joao R. Goncalves
74 
K E Y P O I N T S
•  The treating clinicians must understand the effects of 
osteotomies on normal growth and development so that 
the proper age can be selected to perform surgical 
procedures for specific deformities in growing patients.
•  In double jaw surgery, the selective alteration of the 
occlusal plane may significantly improve the functional 
and esthetic results.
•  The temporomandibular joints (TMJs) provide the 
foundation for orthognathic surgery. Undiagnosed and/or 
untreated pre-existing TMJ dysfunction and pathosis can 
result in unfavorable treatment outcomes, such as 
postoperative pain, condylar resorption, malocclusion, jaw 
dysfunction, and facial deformity.
•  The TMJs should be evaluated properly, and any existing 
TMJ conditions should be discussed with the patient. 
Pre-existing TMJ conditions should be diagnosed 
accurately and treated properly before or at the same time 
as the orthognathic surgical procedures are performed to 
maximize treatment outcomes and stability.
•  Surgeons should know the common pathological TMJ 
conditions and understand the indicated surgical 
management of these conditions when orthognathic 
surgery is required for patients to correct a coexisting 
dentofacial deformity.
•  VSP can significantly improve accuracy of surgical 
movements and decrease the surgeon’s pre-surgical 
preparation time.
•  Dentofacial deformities affect approximately 20% of the 
population with varying degrees of functional and esthetic 
problems. Many patients with moderate to severe 
dentofacial and occlusal deformities can benefit from a 
combination of orthodontics and orthognathic surgical 
treatment to obtain the best outcome results, functionally 
and esthetically.
•  To achieve the best treatment outcomes for patients, the 
treating clinicians must be able to (1) diagnose existing 
problems and deformities correctly, (2) establish an 
appropriate treatment plan, and (3) perform the treatment 
plan properly to completion.
•  Patient evaluation for orthognathic surgery can be divided 
into four main areas: (1) patient concerns, chief 
complaints, and medical history; (2) clinical examination; 
(3) radiographic and imaging analyses; and (4) dental 
model analysis. These analyses provide the information 
necessary to establish comprehensive diagnoses and 
treatment plans.
•  Accurate prediction tracings or virtual surgical planning 
(VSP), dental model surgery, and performance of the 
surgical procedures are paramount to achieve high-quality 
functional and esthetic outcomes.
•  The use of rigid fixation for mandibular and maxillary 
osteotomies with appropriate bone grafting when 
indicated, enhances the treatment outcome  
predictability.
Section 3 Orthognathic Surgery
INTRODUCTION
Dentofacial deformities affect approximately 20% of the popu-
lation. Patients with dentofacial deformities may demonstrate 
various  degrees  of  functional  and  esthetic  compromise.  Such 
malformations may be isolated to one jaw, or they may extend 
to multiple craniofacial structures. Deformities may occur uni-
laterally or bilaterally and may be expressed to varying degrees 
in  the  vertical,  horizontal,  and  transverse  facial  planes.  Many 
patients with dentofacial deformities can benefit  from correc-
tive orthognathic surgical treatment. This chapter focuses pri-
marily on diagnosing and planning treatment for the correction 
of dentofacial deformities.
SURGICAL PLANNING IN ORTHOGNATHIC 
SURGERY
Orthognathic surgery is the art and science of diagnosis, treat-
ment  planning,  and  execution  of  treatment  by  combining 
orthodontics  and  oral  and  maxillofacial  surgery  to  correct 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1049
•  Type of congenital or development deformity
•  Type of acquired deformity
•  Type of musculoskeletal/dento-osseous deformity
•  Type of malocclusion
•  Respiratory problems
•  Sinus or nasal airway disease and/or pathosis
•  Speech problems
•  TMJ dysfunction or pathosis
•  Masticatory and/or swallowing difficulties
•  Psychosocial impairment
•  Bone and/or soft tissue pathoses
•  Infection
•  Bleeding dyscrasias
•  Allergies  or  hypersensitivity  to  surgical  or  orthodontic 
materials
•  Abnormal osseous and/or soft tissue anatomy
•  Compromised vascularity at the surgical site
•  Systemic or localized diseases that may interfere with normal 
healing
•  Myofascial pain dysfunction
•  Ocular or orbital deformity and/or impairment
•  Severity of esthetic facial deformity
•  Poor patient compliance
•  Previous orthodontic and/or orthognathic surgery
•  Neuromuscular abnormalities
Patient Evaluation
Thorough evaluation and diagnosis is one of the most impor-
tant aspects of overall patient management. Failure to recognize 
major  functional  and  esthetic  problems  may  lead  to  com-
promise,  complications,  and  unfavorable  outcomes.  Patient  
evaluation  for  orthognathic  surgery  may  be  divided  into  five 
main areas:
1.  Patient concerns/chief complaints
2.  Medical history
3.  Clinical examination
4.  Radiographic and imaging analysis
5.  Dental model analysis
This  diagnostic  sequence  may  identify  patients  who  are 
candidates  for  orthognathic  surgery  and  determine  whether 
ancillary  dental,  medical,  or  surgical  procedures  may  be  
beneficial.  Such  patients  may  require  further  specialist  evalu-
ation  for  speech,  audiometric,  periodontal,  general  dental, 
psychological,  neurological,  ophthalmological,  medical,  or 
other  concerns.
Patient Concerns
A patient’s ultimate satisfaction with treatment outcome often 
depends on attention to the patient’s chief concerns.1,2 Although 
a change in appearance may be an improvement in the eye of 
the  surgeon  and  may  normalize  a  patient’s  profile  according  
to cephalometric standards, such a change may be undesirable 
to  the  patient.  An  understanding  of  the  patient’s  concerns, 
motivations, and expectations helps define treatment parame-
ters  and  provides  insight  to  the  psychological  health  of  the 
patient. Specific questions that may help  identify  the patient’s 
chief concerns include the following:
•  What are your concerns or problems?
•  Have  you  had  previous  treatment  for  this  condition,  what 
was the treatment, and what was the outcome?
•  Why do you want treatment?
•  What do you expect from treatment?
musculoskeletal, dento-osseous,  and  soft  tissue deformities of 
the  jaws  and  associated  structures.  Successful  orthognathic 
surgery demands the understanding and cooperation of the oral 
and  maxillofacial  surgeon,  orthodontist,  and  general  dentist. 
They  must  provide  a  proper  diagnosis  and  treatment  plan, 
perform the necessary treatment, and refer for necessary treat-
ment outside their respective areas of expertise. Support from 
other  dental  and  medical  professionals  may  be  necessary  to 
provide  the  optimal  functional  and  esthetic  outcome  that 
results  in  patient  satisfaction.  These  specialists  may  include 
periodontists,  prosthodontists,  endodontists,  neurosurgeons, 
ophthalmologists, otolaryngologists, plastic surgeons, psychia-
trists, speech pathologists, and others.
Moderate  to  severe  occlusal  discrepancies  usually  require 
combined orthodontic treatment and orthognathic surgery to 
obtain the most stable result with optimal function and esthet-
ics. The orthodontist is largely limited to the movement of teeth 
and alveolar bone with  little appreciable effect on basal bone. 
The orthodontist’s role is to align and decompensate the teeth 
in relation to the upper and lower jaws. The oral and maxillo-
facial surgeon can move the facial skeleton but cannot provide 
detailed alignment and precise interdigitation of the teeth. The 
oral and maxillofacial  surgeon,  therefore,  repositionsthe  jaws 
and facial structures as dictated by the existing deformities and 
therapeutic goals. For patients to receive state-of-the-art care in 
correction of deformities, the orthognathic team must be able 
to do the following:
•  Correctly diagnose existing deformities
•  Establish an appropriate treatment plan
•  Execute the recommended treatment
Specific  therapeutic  goals  for  orthognathic  surgery  vary 
from  patient  to  patient.  These  goals  are  directed  toward  the 
correction of specific musculoskeletal, dento-osseous, and soft 
tissue  deformities.  The  specific  therapeutic  goals  may  include 
one or more of the following:
•  Correct masticatory and/or swallowing abnormalities
•  Establish  a  functional  occlusion  through  normalization  of 
the  occlusal  relationship,  overbite,  overjet,  occlusal  plane 
angulation, and transverse dimension
•  Correct the inability to open or close the jaws
•  Correct  associated  temporomandibular  joint  (TMJ)  dys-
function, pathosis, or pain
•  Correct  structural  abnormalities  resulting  from  overdevel-
opment or underdevelopment
•  Decrease or eliminate myofascial pain and/or headaches
•  Correct  abnormalities  relating  to  respiratory  compromise; 
for  example,  sleep  apnea,  airway  obstruction,  nasal  septal 
deviation,  snoring,  choanal  atresia,  hypertrophied  turbi-
nates, and nasal polyps
•  Correct speech problems; for example, hypernasal or hypo-
nasal speech, velopharyngeal incompetence, and articulatory 
speech dysfunction
•  Improve  stability of orthodontic and orthognathic  surgery 
results
•  Improve dental and periodontal health
•  Improve psychosocial impairments
Diagnostic  factors and risk factors are conditions that may 
modify  the  treatment planning and affect  the outcome of  the 
surgical procedures. Awareness of potential risk factors is man-
datory for proper treatment planning and for proper preopera-
tive patient counseling. Common diagnostic and risk factors are 
the following:
1050 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
at the most posterior aspect of  the palate while gently closing 
together. An alternate method of obtaining centric relation is to 
have  the  patient  relax  the  mandible  and,  while  keeping  the 
condyles seated, to manipulate the mandible upward until the 
first teeth touch, and ask the patient to hold that position.
For  proper  evaluation,  the  patient’s  lips  should  be  relaxed 
and not forced together. This relaxed lip posture allows evalu-
ation of vertical facial height and the morphology and drape of 
the soft tissues. Relaxation of the lips allows evaluation of upper 
lip  length;  tooth-to-lip  measurements;  possible  lip  incompe-
tence; and coincidence of the facial, dental, and chin midlines. 
Combined with mentalis muscle relaxation, lip relaxation also 
allows  evaluation  of  the  chin  position  and  the  presence  or 
absence  of  skeletal  abnormalities,  such  as  vertical  maxillary 
excess  or  vertical  maxillary  deficiency.  The  lip  posture  fre-
quently  is  overclosed  in  patients  with  vertical  maxillary 
deficiency.
Facial Evaluation
For vertical  facial analysis,  the  face  is most easily divided  into 
equal thirds (see Figure 74-1, A). The upper facial third extends 
from the hairline to the glabella. The middle third extends from 
This assessment of patient concerns helps develop a prelimi-
nary  problem  list  and  helps  identify  patients  with  unrealistic 
expectations.  Patients  with  unrealistic  expectations  must  be 
counseled  so  that  they  understand  the  treatment  limitations 
and  the  likely  outcomes  before  initiation  of  orthodontic  or 
surgical therapy. Patients who maintain unrealistic expectations 
are  best  not  treated.  Patients  must  understand  thoroughly  all 
the treatment options, the anticipated outcomes, and the poten-
tial risks and complications. Situations involving an uninformed 
patient or a patient with unrealistic expectations often result in 
dissatisfaction and may create medicolegal difficulties. Accord-
ingly,  the  surgeon  and  orthodontist  must  be  careful  not  to 
mislead  the  patient  into  perceiving  greater  expectations  than 
can be provided.3-5
System-Oriented Physical Examination
Usually orthognathic surgery is performed on healthy patients. 
This does not, however, diminish the significance of pre-surgical 
evaluation,  including  medical  and  dental  histories,  physical 
examination, and appropriate laboratory studies.6 Obtaining an 
appropriate and current medical history may affect  treatment 
planning  and  may  help  the  surgeon  avoid  potentially  life-
threatening complications. Patient examination should rule out 
or identify patients with difficult airways, connective tissue or 
autoimmune diseases, bleeding disorders, or other pathological 
conditions  that  may  preclude  or  modify  surgery.  Perform  an 
appropriate systemic assessment for every patient.
Patient Preparation for Dentofacial Examination
The patient is evaluated best while sitting upright in a straight-
backed chair with the examiner seated directly opposite at eye 
level. Generally, examine  the patient with his or her pupillary 
plane parallel  to  the floor. Compensatory positioning may be 
appropriate  for  patients  exhibiting  orbital  dystopia.  The  ear 
lobes can be used to establish a plane parallel to the floor. Orient 
the patient’s head so that the clinical Frankfort horizontal plane 
(a line from the tragus of the ear to the bony infraorbital rim) 
is parallel  to  the floor (Figure 74-1, B). This  is a reproducible 
position  that  mimics  the  natural  head  posture  of  most  indi-
viduals with normal facial balance. This position may be used 
to  obtain  standardized  measurements  throughout  the  treat-
ment  sequence.7  Patients  with  dentofacial  deformities  often 
develop alternative head postures  for  functional reasons or  to 
make the deformity less obvious. Adjustment for such compen-
satory head postures is important during clinical, radiographic, 
and photographic evaluation by orienting the clinical Frankfort 
horizontal  plane  parallel  to  the  floor.8  Following  surgical-
orthodontic correction, the natural head posture often reverts 
to a more normal position because functional and esthetic com-
pensation is usually no longer necessary. Selecting a standard-
ized  and  reproducible  head  position  aids  in  proper  diagnosis 
and evaluation of post-treatment results.
Once  the  head  is  oriented  properly,  seat  the  mandibular 
condyles  in  the  glenoid  fossae  with  the  teeth  lightly  touching 
together (centric relation). Although it is important to evaluate 
centric  occlusion,  perform  the  definitive  clinical  examination 
relative to surgical-orthodontic diagnosis and treatment plan-
ning with the patient in centric relation. Failure to evaluate in 
centric  relation  may  result  in  a  misdiagnosis  or  incomplete 
diagnosis,  inappropriate or compromised treatment plan, and 
unacceptable  or  compromised  treatment  outcome.  To  obtain 
centric relation, have the tip of the patient’s tongue positioned 
FIG 74-1 A, Vertically, the face can be divided into equal thirds 
for assessment. The lower third of the face can be divided into 
thirds with the distance from subnasale to upper lip stomion 
equaling one third, and lower lip stomion to soft tissue menton 
equaling two thirds. This ratio provides optimal vertical facial 
balance in the lower third of the face. B, In profile the face is 
divided in the same manner. Head orientation is important, with 
the clinical Frankfort horizontal plane oriented parallel to the 
floor. Clinical Frankfort horizontal plane is a line from the tragus 
of the ear to the bony infraorbitale. 
B
A
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1051
FIG 74-2 The transverse facial balance includesa normal inter-
canthal distance (A) of 32 ±3 mm for whites and 35 ±3 mm for 
blacks and Asians. The normal interpupillary distance (B) is 65 
±3 mm. The width of the palpebral fissures (C) should equal the 
intercanthal distance. 
B
C
A
C
FIG 74-3 Upper lip length is measured from subnasale to upper 
lip stomion. For males, the normal value is 22 ±2 mm, and for 
females, it is 20 ±2 mm. 
FIG 74-4 The normal upper tooth-to-lip relationship is 2.5 
±1.5 mm. 
the glabella to the subnasale. The lower third extends from the 
subnasale to the soft tissue menton. Orthognathic surgery most 
commonly alters  the  lower third of  the  face, with some influ-
ence on the middle  third.  In addition to  this vertical analysis, 
pretreatment  facial  evaluation  also  should  address  the  frontal 
and lateral facial planes. Evaluation from the frontal view should 
include the following 14 anatomical relationships:
1.  Evaluate the forehead, eyes, orbits, and nose for symmetry, 
size, and deformity.
2.  The normal  intercanthal distance  is 32 ±3 mm for whites 
and 35 ±3 mm for blacks and Asians (Figure 74-2).
3.  The normal interpupillary distance is 65 ±3 mm (see Figure 
74-2, distance B).
4.  The  intercanthal  distance,  alar  base  width,  and  palpebral 
fissure  width  should  be  equal  (see  Figure  74-2,  distances  
A and C).
5.  The width of  the nasal dorsum should be one-half of  the 
intercanthal  distance,  and  the  width  of  the  nasal  lobule 
should be two-thirds of the intercanthal distance.
6.  A vertical line through the medial canthus and perpendicu-
lar  to  the  pupillary  plane  should  fall  on  the  alar  bases 
±2 mm (see Figure 74-2).
7.  The upper lip length is measured from subnasale to upper 
lip stomion. The normal upper lip length is 22 ±2 mm for 
males and 20 ±2 mm for females (Figure 74-3).
8.  A  normal  tooth  to  upper  lip  relationship  exposes  
2.5  ±1.5 mm  of  incisal  edge  with  the  lips  in  repose 
(Figure 74-4).
9.  The facial midline, nasal midline, lip midlines, dental mid-
lines, and chin midline should be congruent, and the face 
should  be  reasonably  symmetrical,  vertically  and  trans-
versely (Figures 74-5 and 74-6).
10.  If the patient’s lips are overclosed, rotate the jaws open until 
the lips just begin to separate. The condyles should remain 
seated in centric relation. Then evaluate the true lip length 
and the tooth-to-lip relationship.
11.  The smile is frequently one of the patient’s chief concerns. 
When smiling, the vermilion of the upper lip should fall at 
the cervical gingival margin with no more than 1 to 2 mm 
of exposed gingiva. In addition to this relationship, surgical 
decisions  also must  consider  the  tooth-to-lip  relationship 
with the lips in repose, because many factors may influence 
lip  posture  during  animation.  The  amount  of  upper  lip 
elevation during smiling may be affected by the following:
a.  Anteroposterior  (AP)  position  of  the  maxilla  and  
mandible  in  relation  to  the  cranial  base  as  well  as  to  
each other
b.  Amount of overjet and overbite
c.  Angulation of the anterior dentoalveolus
1052 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
inferior aspect of  the  iris and  the  lower  lid (scleral  show) 
may indicate infraorbital hypoplasia or exophthalmos.
13.  The  distance  from  glabella  to  subnasale  and  subnasale  to 
menton should be approximately a 1 : 1 ratio, providing that 
the upper lip length is normal (see Figure 74-1, A).
14.  The  length  of  the  upper  lip  should  be  one-third  of  the 
length of the lower facial third; that is, lower lip stomion to 
soft tissue menton should be twice the vertical dimension 
of the upper lip, providing that the upper lip is normal in 
length (see Figure 74-1, A).
Lateral view. Evaluation of the lateral facial view is usually 
the  most  valuable  assessment  in  determining  vertical  and AP 
problems of the jaws:
1.  The distance from glabella to subnasale and from subnasale 
to soft  tissue menton should be  in a 1 : 1 ratio  if  the upper 
lip length is normal (see Figure 74-1, B).
2.  With the maxilla in the normal AP position and the upper 
lip of normal thickness, the ideal chin projection is 3 ±3 mm 
posterior  to a  line  through subnasale  that  is perpendicular 
to the clinical Frankfort horizontal plane (subnasale perpen-
dicular plane (Figure 74-7).
3.  Evaluate the morphology and relationships of the nose, lips, 
cheeks, and chin.
4.  Evaluate  the  cervicomandibular  angle  in  reference  to  the 
chin position.
5.  The  length  of  the  upper  lip  should  be  one-third  of  the  
length of the lower facial third; that is, lower lip stomion to 
soft  tissue  menton  should  be  twice  the  vertical  dimension  
of  the  upper  lip  if  the  upper  lip  is  normal  in  length  (see 
Figure 74-1, B).
6.  The upper lip labrale superius should be 1 to 3 mm anterior 
to the subnasale perpendicular plane.
7.  A  line  perpendicular  to  Frankfort  horizontal  plane  and 
tangent  to  the  globe  should  fall  on  the  infraorbital  soft 
tissues ±2 mm (see Figure 74-7).
d.  Occlusal plane angulation
e.  Clinical crown length
f.  Neuromuscular function of the lips
g.  Dental coverage of periodontium
Each of these factors may contribute to inaccuracies in the 
determination of the proper maxillary vertical position 
if  this  position  is  determined  only  by  evaluation  of  
the tooth-to-lip position during smiling.
12.  The lower eyelid should be level with or slightly above the 
most  inferior  aspect  of  the  iris.  The  sclera  between  the 
FIG 74-5 The facial midlines are assessed, including the nasal, 
maxillary and mandibular dental midlines, and the chin midline, 
relative to the facial midline. Left-to-right facial symmetry also 
is evaluated. 
FIG 74-6 Transversely, the occlusal plane should parallel the 
pupillary plane, providing there is no orbital dystopia. 
FIG 74-7 A line perpendicular to the clinical Frankfort horizontal 
plane (CIFH) through subnasale (A) should be 3 ±3 mm anterior 
to the chin. A line tangent to the globe, perpendicular to clinical 
Frankfort horizontal plane (B) should fall on the infraorbital soft 
tissues ±2 mm. 
B
ClFH
A
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1053
condylar resorption, malocclusion, jaw dysfunction, and facial 
deformity.15,16
Assess the TMJs before treatment and periodically through-
out  treatment.  Basic  TMJ  factors  to  consider  include  the 
following:
1.  The  patient  history  may  reveal  headaches,  ear  problems, 
myofascial  pain,  TMJ  dysfunction,  clicking  and  popping, 
crepitation,  limited  opening,  pain,  difficulty  chewing,  pro-
gressive development of an open bite, shifting of  the man-
dible  and  bite,  neck  and  shoulder  problems,  and  so  on. 
Document  etiological  factors,  time  of  onset,  signs  and  
symptoms,  previous  treatments  and  outcomes,  symptom 
frequency  and  duration,  parafunctional  habits,  and  other 
modifying factors.
2.  Identify or rule out polyarthritides or other systemic condi-
tions.  These  conditions  may  include  connective  tissue  or 
autoimmune diseases, such as rheumatoid arthritis, juvenile 
idiopathic  arthritis,  systemic  lupus  erythematosus,  sclero-
derma,  sarcoidosis,  reactive  arthritis,  psoriasis,  psoriatic 
arthritis, Sjögren disease, ankylosing spondylitis, and Reiter 
syndrome.15,16
3.  Clinical examination should assess pain, function, and joint 
noise.  Deviation  of  the  mandible  during  opening,  for 
example,  may  indicate  a  unilateral  closed  lock  or  fibrous 
ankylosis.  Joint  noises  such  as  clicking  and  popping  may 
suggest  articular  disk  displacement.  Crepitation  within  
the  joint  may  indicate  osteoarthritis  or  perforation  of  the 
retrodiscal tissues.
4.  Obtain and evaluate cone beam imaging, panoramic radio-
graphs,transcranial  radiographs,  transpharyngeal  radio-
graphs,  tomograms,  computed  tomography  (CT)  scans, 
magnetic  resonance  imaging  (MRI),  and  other  imaging 
modalities as indicated.
5.  Properly diagnose existing TMJ conditions and discuss them 
with the patient. The surgeon should properly sequence and 
plan treatment for conditions requiring correction. Inform 
the  patient  of  any  abnormal  TMJ  findings  and  how  such 
conditions may influence the orthodontic and orthognathic 
surgery  outcome,  even  if  these  conditions  do  not  require 
intervention.
The nose. Take a history relative  to previous nasal  trauma, 
nasal  airway  obstruction,  allergies,  sinus  problems,  predomi-
nate mouth breathing versus nasal breathing, esthetic concerns, 
and previous surgery. A functional and esthetic nasal evaluation 
should include thorough examination of internal and external 
nasal  structures.  Perform  esthetic  evaluation  of  the  external 
nasal  anatomy  from  frontal  and  profile  views.  Note  scars, 
lesions, soft tissue thickness, asymmetries, and evidence of pre-
vious surgeries. From the frontal view, the normal intercanthal 
distance  is  32  ±3 mm  (see  Figure  74-2).  The  normal  dorsal 
width is one-half of this measurement, and the normal lobule 
width  is  two-thirds  of  this  distance.  The  nasal  dorsal  length 
should fill most of the middle third of the face. No more than 
one-third  of  the  vertical  dimension  of  the  nares  should  be 
visible from the frontal view.
From the clinical and radiographic profile view, the nasion 
should  be  at  the  same  vertical  level  as  the  upper  palpebral 
crease. The nasal dorsum should be straight to slightly concave. 
The  normal  nasolabial  angle  ranges  from  90  to  105  degrees 
(Figure  74-8,  angle  A).  The  normal  nasal  projection  angle,  
measured  by  a  line  tangential  to  the  nasal  dorsum  relative  to  
a  line  perpendicular  to  the  Frankfort  horizontal  plane  (see 
Oral examination. Oral  examination  helps  identify  func-
tional  and  esthetic  deformities  of  the  dento-osseous  and  soft 
tissue  structures.  Thorough  oral  examination  should  address 
the following issues:
•  Occlusal relationship (Class I, II, or III)
•  Anterior overbite or open bite
•  Anterior overjet and any crossbites
•  Health of the dentition
•  Tooth size discrepancies
•  Curve of Wilson
•  Curve of Spee
•  Dental crowding or spacing
•  Missing, decayed, retained primary, nonsalvageable teeth
•  Discrepancies  between  centric  occlusion  and  centric 
relation
•  Periodontal evaluation
•  Transverse, AP, or vertical asymmetries
•  Anatomical or functional tongue abnormalities
•  Any masticatory difficulties
•  Any other pathological processes
Occlusal factors to be evaluated in the oral examination are 
discussed in the Dental Model Analysis section.
Periodontal evaluation. There are several periodontal factors 
that  should  be  evaluated  before  orthodontic  treatment  and 
orthognathic  surgery.  Patients  with  pre-existing  periodontal 
disease or gingivitis have an increased risk of disease exacerba-
tion during orthodontic treatment and post treatment, particu-
larly in areas where interdental osteotomies may be required.9 
Factors that can affect periodontal health adversely in relation 
to  orthognathic  surgery  include  smoking,  excessive  alcohol  
or  caffeine  consumption,  bruxism  and  clenching,  connective 
tissue/autoimmune  diseases,  diabetes,  malnutrition,  and  so 
on.10 Address  all  periodontal  disease  before  orthodontics  and 
orthognathic surgery.
Inadequate attached gingiva, most frequently associated with 
the mandibular anterior teeth, may contribute to the develop-
ment of periodontal problems, such as gingival retraction, tooth 
sensitivity,  and  bone  loss.  In  areas  of  inadequate  attached 
gingiva,  consider  gingival  grafting.  When  indicated,  perform 
free  gingival  grafts  or  free  connective  tissue  grafts  before  the 
initiation of orthodontics. Gingival grafting should occur before 
orthodontic treatment because orthodontic tipping and surgi-
cal incisions for genioplasty, subapical osteotomies, and vertical 
interdental osteotomies may worsen periodontal problems dra-
matically.  Providing  adequate  attached  gingival  tissue  before 
orthodontic  and  orthognathic  surgical  intervention  protects 
this tissue and minimizes gingival tissue retraction.
Orthognathic  surgical  techniques  must  protect  the  peri-
odontal tissues and minimize vascular compromise to the bone, 
teeth, and soft tissues. Take care to maintain bone around the 
necks  of  each  of  the  teeth  at  the  interdental  osteotomy  sites. 
Orthodontics can  facilitate  interdental osteotomies by  tipping 
the  roots  of  the  teeth  away  from  the  osteotomy  site.  Several 
studies demonstrate that with such orthodontic assistance and 
careful  surgical  technique,  interdental  osteotomies  have  a 
minimal effect on the periodontium.11-14 The failure to identify 
risk  factors,  poor  surgical  technique,  and  lack  of  attention  to 
detail can result in devastating periodontal complications.
Temporomandibular joints. The  TMJs  provide  the  founda-
tion  for  orthognathic  surgery.  Pre-surgical  TMJ  dysfunction  
or  undiagnosed  TMJ  pathosis  can  result  in  orthognathic  
surgery  unfavorable  outcomes,  such  as  postoperative  pain, 
1054 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
of  jaw  deformities.16  The  lateral  cephalometric  radiograph  is 
used to analyze skeletal, dentoalveolar, and soft tissue relation-
ships in the AP and vertical dimensions. For proper positioning, 
pose the patient’s head so that  the  jaws are  in centric relation 
with the teeth lightly touching and the lips relaxed. Position the 
head so  that  the clinical Frankfort horizontal plane  is parallel 
to  the  floor.  Both  hard  and  soft  tissue  structures  should  be 
visible on the radiograph. If the patient’s bite is overclosed (such 
as  in  vertical  maxillary  deficiency),  then  take  a  second  lateral 
cephalometric  radiograph  with  the  condyles  still  seated  in 
centric relation but the mouth opened until the lips just begin 
to  separate.  This  posture  allows  assessment  of  soft  tissue  and 
bony structures without distortion of the lips. AP cephalomet-
ric  radiographs  may  be  helpful,  particularly  in  diagnosing  
and treatment planning for patients with significant transverse 
asymmetries.
Cephalometric analysis versus clinical diagnosis. Numerous 
cephalometric analyses are available to evaluate lateral cephalo-
metric radiographs. Regardless of the specific analysis the clini-
cian  uses,  it  is  important  to  understand  that  there  may  be 
significant differences between  the clinical  evaluation and  the 
values  obtained  from  cephalometric  analysis.  When  a  signifi-
cant difference occurs, the clinical evaluation is far more impor-
tant for treatment planning.17 Cephalometric analysis is only an 
aid  to  clinical  assessment  and  should  not  be  used  as  the  sole 
diagnostic tool.
Corrected Frankfort horizontal plane. In  cases  in  which  the 
cephalometric values do not correlate with the clinical impres-
sion, make adjustments in the reference cranial base structures 
(i.e., corrected Frankfort horizontal line). Adjust values to cor-
relate  with  the  clinical  impression  for  use  in  diagnosis  and 
treatment  planning.  The  Frankfort  horizontal  plane  may  be 
positioned aberrantly because of vertical malposition of porion 
or orbitale and/or AP malposition of nasion. A proper Frank-
fort horizontal plane also may be difficult to locate because of 
difficulty in the radiographic identification of porion or orbitale. 
A corrected Frankfort horizontal plane to correlate the cepha-
lometric  values  for  maxillary  and  mandibular  positions  with 
the  clinicalimpression  provides  a  cephalometric  analysis  that 
assists  in  diagnosis  and  treatment  planning  (Figure  74-9). 
Cephalometric analysis tempered with good clinical judgment 
can  be  a  valuable  tool  in  establishing  the  most  appropriate 
orthodontic and surgical treatment plan.
Cephalometric analysis. Many  reasonable  cephalometric 
analyses are available for clinical decision making.17 The authors 
use  an  analysis  that  evaluates  15  cephalometric  relationships. 
This analysis permits a rapid diagnostic assessment as follows:
1.  Maxillary depth is an angular measurement formed by the 
Frankfort horizontal plane and a line from nasion through 
point  A  (NA  line).  The  normal  value  is  90  ±3  degrees 
(Figure 74-10, angle A).
2.  Mandibular  depth  is  the  angle  formed  by  the  Frankfort 
horizontal plane and a line from nasion through point B of 
the mandible (NB line). The normal value is 88 ±3 degrees 
(see Figure 74-10, angle B).
3.  The Frankfort mandibular plane angle is the angle created 
by a  line from the menton through the gonion relative to 
the Frankfort horizontal plane. The normal value is 25 ±5 
degrees (see Figure 74-10, angle C).
4.  Occlusal plane angulation is determined from a line drawn 
tangent  to  the  buccal  groove  of  the  mandibular  second 
molar through the cusp tips of the premolars and the angle 
Figure 74-8, angle B), is 34 degrees for females and 36 degrees 
for males. The columella  should extend 3  to 4 mm below the 
lateral alar rims. The distance ratio  from the base of  the nose 
to the anterior extent of the nares and from the anterior aspect 
of  the  nares  to  the  tip  of  the  nose  should  be  2 : 1.  The  nares 
should  be  symmetrical.  Radiographic  films  most  helpful  in 
identifying  nasal  and  paranasal  sinus  pathoses  include  cone 
beam  imaging,  but  also  lateral  cephalometric  radiograph, 
Water’s  view,  posteroanterior  cephalometric  radiograph,  soft 
tissue  nasal  radiographs,  and  CT  scan.  Perform  a  thorough 
intranasal examination to identify any existing airway obstruc-
tion or pathosis, including nasal septal deviation, hypertrophied 
turbinates, nasal polyps, or nasopharyngeal adenoid hyperplasia.
Radiographic Evaluation
Types of Imaging Techniques
Cone  beam  technology  provides  a  1 : 1  ratio  of  imaging  with 
panogram, cephalometric, and tomographic imaging, including 
three-dimensional imaging, and it is currently the gold standard 
for orthognathic surgery imaging. Other commonly used radio-
graphs  for  diagnosis  of  dentofacial  deformities  are  (1)  lateral 
cephalometric radiograph, (2) panoramic radiograph, and (3) 
periapical radiograph when indicated. Panoramic and periapi-
cal  radiographs  can be helpful  to determine  tooth alignment, 
root angulation, and existing pathoses. Other imaging modali-
ties  such  as  posteroanterior  cephalograms,  TMJ  tomograms, 
transcranial  radiographs,  Water’s  view  images,  MRI,  and  
CT  scans  may  be  required  as  determined  by  individualized 
patient needs.
Lateral cephalometric radiograph. The lateral cephalometric 
radiograph is one of the most important tools in the diagnosis 
FIG 74-8 The normal nasolabial angle (A) is 90 to 105 degrees. 
The normal nasal projection angle with a line tangent to the 
dorsum of the nose and the angle created by a line perpendicu-
lar to Frankfort horizontal plane (B) should be 36 degrees for 
males and 34 degrees for females. 
A
90°
B
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1055
of  this  line  relative  to  the  Frankfort  horizontal  plane.  
The normal value  is 8 ±4 degrees. The occlusal plane has 
significant influence on function and esthetics, particularly 
when double  jaw  surgery  is performed  (see Figure 74-10, 
angle D).
5.  The  esthetic  line  (see  Figure  74-10,  red  line  labeled  E) 
relates a line tangent to the labial surface of the maxillary 
central  incisors  extended  vertically  to  cross  the  Frankfort 
horizontal plane and should form a 90-degree angle when 
ideally aligned. This places the central incisor crown in the 
best esthetic position. 
6.  Upper incisor angulation relates the long axis of the maxil-
lary incisor to the NA line and is normally 22 ±2 degrees. 
The  labial  surface  of  the  incisor  tip  should  be  4 ±2 mm 
anterior to the NA line. Upper incisor angulation is impor-
tant  in  establishing  the  pre-surgical  orthodontic  goals 
(Figure 74-11, angles A and B).
7.  The  lower  incisor  angulation  relates  the  long  axis  of  the 
mandibular  incisor  to  the  NB  line  and  is  normally  20 
±2  degrees.  The  labial  surface  of  the  incisor  tip  should 
be  4  ±2  mm  anterior  to  the  NB  line.  Assessment  of  the 
lower  incisor  angulation  is  important  in  determining  the 
pre-surgical  orthodontic  goals  (see  Figure  74-11,  angles 
C  and  D).
FIG 74-9 Commonly, the anatomical Frankfort horizontal plane 
(A) may not correlate to the clinical impression or the patient’s 
deformity. In such instances, a corrected Frankfort horizontal 
plane can be constructed (B) so that the numerical cephalomet-
ric values correlate to the clinical diagnosis of the patient. 
B
A
FIG 74-10 A normal maxillary depth (A) is 90 ±3 degrees. The 
normal mandibular depth (B) is 88 ±3 degrees. The normal 
mandibular plane angle to Frankfort horizontal plane (C) is 25 
±5 degrees. The normal occlusal plane angle (D) is 8 ±4 degrees. 
The normal esthetic line (red line designated E) is 90 ±2 degrees. 
A
B
D
E
C
FIG 74-11 The long axis from the upper incisor to the NA line 
(A) has a normal value of 22 ±2 degrees. The labial surface of 
the upper incisor (B) should be 4 ±2 mm anterior to the NA line. 
The long axis of the lower incisor to the NB line (C) has a normal 
value of 20 ±2 degrees. The labial surface of the mandibular 
central incisors (D) should be 4 ±2 mm anterior to the NB line. 
Hard tissue pogonion (E) should be 4 ±2 mm anterior to the NB 
line with a 1 : 1 ratio, with the position of the labial surface of 
the mandibular central incisors anterior to the NB line. 
A
B
D
C
E
1056 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
8.  The pogonion projection is measured from the most pro-
trusive  point  of  bony  pogonion  to  the  NB  line  with  a 
normal relationship of 4 ±2 mm. Optimal mandibular den-
toskeletal balance is achieved when the labial surface of the 
lower incisors and pogonion are in a 1 : 1 ratio anterior to 
the NB line (see Figure 74-11, distance E).
9.  The upper lip length is measured from the base of the nose 
(subnasale) to the inferior part of the upper lip (upper lip 
stomion).  The  normal  length  of  an  adult  male  lip  is  22 
±2 mm. For a  female,  it  is 20 ±2 mm. Upper  lip  length  is 
the basis  for  establishing vertical  facial dimensions  in  the 
lower third of the face because the upper lip length usually 
is not altered easily. This measurement is the basis for estab-
lishing  the  vertical  length  of  the  lower  two  thirds  of  the 
lower third of the face (Figure 74-12, distance A).
10.  The upper  tooth-to-lip relationship  is measured from the 
relaxed upper lip stomion to the incisal edge of the upper 
incisor. The normal value is 2.5 ±1.5 mm. This evaluation 
is important in establishing the vertical dimensions of the 
face, particularly when there are vertical dysplasias present 
in the maxilla (see Figure 74-12, distance B).
11.  The  lower  anterior  dental  height  is  measured  from  the 
lower incisor tip to hard tissue menton. The average lower 
FIG 74-12 Normal upper lip length (A) for a male is 22 ±2 mm 
and for females is 20 ±2 mm. Normal tooth-to-lip relationship 
(B) is 2.5 ±1.5 mm. The lower anterior dental height (C) is mea-
sured from the mandibular central incisor tips to hard tissue 
menton. It has a normal value of 44 ±2 mm in males and 40 ±2 
mm in females.An important interrelationship is two times the 
upper lip length should equal the lower anterior dental height. 
The soft tissue thickness of the upper lip, lower lip, and chin 
area (D) usually ranges from 11 to 14 mm but more importantly 
should be a 1 : 1 : 1 ratio. The soft tissue thickness in the menton 
area (E) is normally 7 ±2 mm. 
A
D
D
C
B
D
E
anterior  dental  height  for  a  male  is  44 ±2 mm,  and  for  a 
female  it  is  40 ±2 mm.  For  optimal  balance  in  the  lower 
third of the face, the lower anterior dental height should be 
approximately twice the upper lip length. If the upper lip is 
longer than normal, then the lower anterior dental height 
should be longer than normal so that the facial dimensions 
will be balanced in the lower facial third (see Figure 74-12, 
distance C).
12.  The soft tissue thickness of the upper lip, lower lip, and chin 
area normally ranges from 11 to 14 mm. More importantly, 
there should be a 1 : 1 : 1 ratio. Variations in this ratio may 
influence  treatment  planning  decisions  regarding  the  lips 
and chin (see Figure 74-12, distance D).
13.  The  soft  tissue  thickness  of  the  menton  is  measured  per-
pendicular to Frankfort horizontal plane from hard tissue 
menton to soft tissue menton. The normal dimension is 7 
±2 mm.  Excessive  thickness  or  thinness  of  this  area  may 
influence alterations in the height of the anterior mandible 
(see Figure 74-12, distance E).
14.  The  nasal  projection  angle  is  a  line  tangent  to  the  soft  
tissue  of  the  nasal  dorsum  and  a  line  perpendicular  to 
Frankfort  horizontal  plane  through  soft  tissue  nasion. 
Normal is 34 degrees for females and 36 degrees for males 
(see Figure 74-8, angle B).
15.  The  nasolabial  angle  is  a  line  tangent  to  the  columella 
through the subnasale and a line tangent to the upper lip. 
The  normal  range  is  90  to  105  degrees  (see  Figure  74-8, 
angle A).
Dental Model Surgery
Many  techniques  for  model  surgery  have  been  proposed.  In 
two-jaw  surgery,  most  surgeons  advocate  positioning  the 
maxilla  first  and  fabricating  an  intermediate  splint  with  the 
intact  mandible  and  the  repositioned  maxilla.  An  alternative 
technique, however, may provide improved surgical accuracy by 
avoiding intraoperative maxillary shifting during the placement 
of  intermaxillary fixation caused by excessively  thin maxillary 
walls or by  intermaxillary  instability during  large mandibular 
advancements.18
This  alternative  technique  involves  repositioning  the  man-
dible first, rigidly stabilizing it, and then repositioning and sta-
bilizing  the  maxilla.  After  mounting  the  dental  models  on  a 
semiadjustable articulator using an occlusal plane indicator or 
a face-bow transfer and centric bite registration, carefully trim 
the models.19 Trim the mandibular model with its base flat on 
the  anterior  aspect.  Then  trim  the  base  of  the  mandibular 
model  to  form  a  rectangular  column  of  plaster  beneath  the 
model, using the initial anterior surface as the starting reference 
plane (Figure 74-13). Next,  trim the maxillary model and the 
base flat from the canine to molar region bilaterally, with these 
cuts parallel to the dentition. Then trim the anterior and pos-
terior aspects of the maxillary model and base flat, parallel  to 
each other and perpendicular  to  the base and the AP midline 
(Figure  74-14).  Draw  three  horizontal  reference  lines  5 mm 
apart around each of the models. Then place three to five verti-
cal lines on each side of the models. The reference lines quantify 
AP, vertical, and transverse movements of the mandible relative 
to the maxillary teeth and articulator base.
Take  measurements  from  the  surgical  treatment  objective 
(STO;  or  prediction  tracing)  to  determine  the  position  of  
the  mandible  for  model  surgery.  Superimpose  the  STO  over  
the original cephalometric analysis. A pencil point held at the 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1057
FIG 74-13 The base of the mandibular model is trimmed to 
form a rectangular column of plaster beneath the model. Place-
ment of the reference lines allows better control of mandibular 
orientation when moving it anteroposteriorly or transversely. 
FIG 74-14 The maxillary model is trimmed so that the plaster 
walls are trimmed parallel in relation to the buccal aspects of 
the posterior teeth. 
FIG 74-15 To determine the anteroposterior (AP) position of 
the mandible in relation to the unoperated maxilla, a pencil point 
is held in the midpoint of the condylar head. The prediction 
tracing is rotated so that the mandible on the surgical treatment 
objective (STO) articulates with the maxilla on the cephalomet-
ric tracing where initial tooth contact is projected to occur. This 
relates the AP position of the mandible in relation to the unoper-
ated maxilla. This relationship then should be reproduced in the 
model surgery. 
LM
pre-op
predicted mand.
FIG 74-16 The mounted mandibular model is repositioned on 
the articulator to correlate to the anteroposterior (AP) move-
ments achieved on the surgical treatment objective (STO). The 
resultant interdental relationship can be duplicated in surgery 
with the use of an intermediate splint made on the models in 
this position. The incisal pin is not altered in length. The man-
dibular model is repositioned by removing plaster from the 
bottom of the cast. The intermediate splint is constructed. 
condylar  area  allows  rotation  of  the  STO,  in  relation  to  the 
underlying cephalometric tracing, until the first dental contact 
occurs between  the mandible on  the STO and  the maxilla on 
the original cephalometric tracing (Figure 74-15). This spatially 
gives the AP vertical and occlusal plane orientation of the repo-
sitioned mandible  relative  to  the  uncut maxilla. Then  cut  the 
mandibular plaster model free of its base and reposition it into 
its new position as predetermined by the STO and cephalomet-
ric tracings (Figure 74-16). The incisal pin is not altered verti-
cally at all. Remove any interferences on the plaster base from 
the inferior base attached to the mounting ring or the under-
surface  of  the  resected  mandibular  model.  Then  secure  the 
mandible in its new position with sticky wax or glue. Fabricate 
an intermediate splint to aid in positioning the mandible at the 
time of surgery.
Then cut the maxillary model off its base at the approximate 
level of the anticipated Le Fort osteotomy. The maxilla may be 
sectioned  to  obtain  the  best  functional  and  occlusal  relation-
ship. Trim interferences, and interdigitate the maxillary occlu-
sion  to  the  best  possible  dental  relationship  and  fix  it  to  the 
maxillary base  (Figure 74-17). To maximize accuracy,  remove 
1058 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
to  2 mm  thickness  of  wax  so  that  the  palatal  mucosa  is  not 
impinged, because this could cause vascular compromise to the 
maxillary segments (see Figure 74-18).
This splint design provides transverse stability of the maxil-
lary arch yet allows a maximal occlusal inter-relationship. These 
splints can be wired in place for 1 to 2 months and then con-
tinued for an additional 2 to 3 months as a removable appliance 
to maximize the transverse stability. Place  interdental holes  in 
the  splint  so  that  it  can  be  ligated  to  the  teeth,  maxillary  
first molars and the first premolars. The anterior teeth are not 
ligated  into  the  splint,  but  the  interdigitation  of  the  splint  to 
those teeth can help maintain the AP position (Figure 74-19). 
The  palatal  splint  is  preferred  to  an  occlusal  covering  splint, 
because  it  significantly  decreases  occlusal  discrepancies  and 
allows maximal interdigitation of the maxillary and mandibular 
teeth at surgery, thus decreasing potential post-surgicalocclusal 
problems. Shifting between the reference lines on the mobilized 
portion of the models and the stable bases is useful at the time 
of surgery to help correlate the same movements. Accurate pre-
diction  tracings,  model  surgery,  and  splint  fabrication  greatly 
simplify the surgery. When the mandible is positioned first, the 
only measurement required during surgery is the vertical posi-
tion of  the maxillary central  incisors. Proper use of  the man-
dibular inferior border reciprocating saw blade reduces the risk 
of a bad splint and facilitates predictable mandibular first surgi-
cal sequencing.20
Maxillary  surgery  can  be  performed  first,  but  segmental 
surgery  requires  the  construction  of  intermediate  and  final 
splints. With a final  splint  that  covers  the occlusal  surfaces of 
the maxillary teeth, the intermediate splint must join the man-
dibular teeth and the undersurface of the final splint. Surgical 
stability may be compromised if the maxilla is repositioned first 
and large mandibular advancements are required. Mandibular 
advancement may stress the maxillary bone plates to the degree 
that  the  maxillomandibular  complex  can  rotate  backward 
before rigid fixation is applied to the mandible. This may result 
in a functional and esthetic compromise.
Orthodontics Without Prior Surgical Consideration
Occasionally,  orthodontic  treatment  is  initiated  before  the  
need for surgery  is recognized. When this situation arises,  the 
orthodontist  and  surgeon  should  compare  the  pretreatment 
the plaster or add wax between the mobilized segments and the 
stable base  to  simulate vertical changes.  In cases  in which  the 
maxilla  is  to  be  surgically  expanded  or  spaces  created  in  
the interdental cut area, a palatal splint is constructed to provide 
transverse stabilization (Figure 74-18). This splint creates trans-
verse  stability  by  interdigitating  along  the  palatal  surfaces  of  
the  dentition.  The  palatal  splint  is  designed  without  occlusal 
coverage.  We  prefer  to  section  the  maxilla  into  three  pieces 
between the lateral incisors and canines. Once the segments are 
positioned properly and stabilized, wax out the palate with a 1 
FIG 74-17 The maxilla then is mobilized and sectioned, if indi-
cated, and placed into occlusion to maximize the dental inter-
cuspation and final splint constructed. The incisal pin can remain 
in the original to accurately reposition the maxilla relative to the 
base, or as seen in this figure, the pin was lowered decreasing 
the amount of “fill” required between the maxillary model and 
the base. 
FIG 74-18 Transverse stability of the segmentalized maxilla can 
be achieved using a palatal splint. The soft tissues on the palate 
must be waxed out, providing approximately 2 mm of wax relief 
so that there is no impingement on the palatal soft tissues that 
could compromise blood supply to the maxilla. This splint does 
not cover the occlusal surface of the teeth. The transverse 
palatal stability is achieved by contact of the splint against the 
palatal aspects of the maxillary teeth. 
FIG 74-19 The maxillary splint is seated and secured. Light-
gauge wires usually engage the first molars and first premolars 
bilaterally. The anterior teeth are not ligated into the splint. 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1059
records with records that show the patient’s present condition. 
They must assess the stability of the orthodontic mechanics. If 
concerns arise about instability of the dental alignment within 
the arches, then the arch wires can be sectioned to allow vertical 
and transverse relapse while maintaining the correction of any 
rotations. Allow the teeth to settle for 4 to 6 months if signifi-
cant unstable movements have been performed, such as rapid 
palatal expansion, orthodontic expansion, orthodontic closing 
of open bites, or dental extrusion or intrusion. Reevaluate the 
patient  with  new  records  after  stabilization  to  establish  the 
proper diagnosis and treatment goals.
Diagnostic List
Before developing a treatment plan, establish a list of all existing 
problems evident from clinical, radiographic, dental model, and 
other  indicated  evaluations.  This  problem  list  should  include 
skeletal  imbalances,  occlusal  problems,  esthetic  concerns,  
temporomandibular  dysfunction,  myofascial  pain,  missing 
teeth,  crowns,  bridges,  endodontically  treated  teeth,  dental 
implants, periodontal problems, or other functional disorders. 
The diagnostic  list  includes all  functional, esthetic, and dental 
problems, as well as any other medical  factors  that may affect 
treatment  outcomes.  Formulate  the  treatment  plan  from  the 
problem list.
Initial Surgical Treatment Objective
The STO, or prediction tracing, is a two-dimensional projection 
of  the  osseous,  dental,  and  soft  tissue  changes  resulting  from 
surgical orthodontic correction of orthodontic and orthopedic 
deformities.21 The purpose of the STO is threefold: (1) to estab-
lish  orthodontic  goals,  (2)  to  develop  surgical  objectives,  and 
(3)  to create  the predicted  facial profile  that  can be used as a 
visual  aid  in  patient  consultation.  The  STO  has  significant 
importance  in  two  phases  of  treatment  planning.  The  initial 
STO is prepared before treatment to determine orthodontic and 
surgical goals. The final STO is prepared after active orthodon-
tic treatment and before surgery to determine the exact vertical 
and AP changes to be achieved. The STO is important in estab-
lishing treatment objectives and projected results as a diagnostic 
aid and a treatment planning blueprint.
Double Jaw Surgery
After the cephalometric tracing is complete, draw the surgical 
reference lines on it to mimic the actual position of the surgical 
sites (Figure 74-20). Three critical decisions to make when plan-
ning double jaw surgery are the following:
1.  The vertical position of the maxillary incisor
2.  The AP position of the maxillary incisor
3.  The occlusal plane angulation
Draw  these  lines  on  the  STO  after  tracing  all  stable  land-
marks (Figure 74-21, A). Position the anterior maxillary segment 
on the cephalometric tracing on the STO by placing point A on 
the normal NA line and placing the incisor tip on the vertical 
and  AP  reference  lines  (90  degrees  to  Frankfort  horizontal 
plane) and tracing it onto the STO (see Figure 74-21, B). With 
the mandible positioned onto the STO in relation to the maxil-
lary incisors and the occlusal plane angulation (Figure 74-22), 
trace the distal mandibular segment onto the STO. Then align 
the proximal mandibular segment onto the STO with the distal 
segment  and  trace  it  (Figure  74-23).  Position  the  posterior 
segment of the maxilla onto the STO to interdigitate best with 
the  mandibular  dentition  (Figure  74-24).  Trace  the  surgical 
FIG 74-20 In double jaw surgery, the surgical reference lines 
are drawn on the cephalometric tracing to mimic the actual 
position of the surgical cuts. Note the vertically directed line 
between the maxillary lateral incisor and cuspid, representing 
the interdental osteotomy. 
reference  lines  onto  the  STO  with  each  segment.  Once  the 
maxilla and mandible are positioned onto the STO, then deter-
mine  the  chin  position.  The  NB  line  provides  a  convenient 
reference for determination of the AP position of bony pogo-
nion. The ratio between the distances from the labial surface of 
the  mandibular  central  incisors  to  the  NB  line  and  from  the 
pogonion to the NB line should be 1 : 1 (Figure 74-25). Measure 
the vertical dimension of the anterior mandible from the tip of 
the  mandibular  central  incisors  to  hard  tissue  menton.  For 
optimal esthetics, this dimension should equal twice the upper 
lip  length. Trace appropriate alteration of  the bony chin onto 
the  STO.  Then  add  thesoft  tissues  to  complete  the  STO. 
Compare  skeletal,  dental,  and  soft  tissue  changes  on  the  STO 
with the original cephalometric  tracing. Record these changes 
on  the  STO.  The  STO  now  provides  the  blueprint  for  dental 
model surgery and the actual surgical procedures.
Soft Tissue Changes
The soft tissue changes discussed assume that an alar base cinch 
suture and an intraoral V-Y closure are used to close the maxil-
lary incision. The upper lip labrale superius advances approxi-
mately  80%  the  amount  of  maxillary  advancement  (Figure 
74-26, A). In maxillary setbacks, the upper lip moves posteriorly 
about  50%  the  amount  of  AP  movement  of  the  maxilla  (see 
Figure 74-26, B). Superior repositioning of the maxilla shortens 
the upper lip 10% of the amount of the vertical movement (see 
Figure 74-26, C), and down-grafting the maxilla lengthens the 
upper  lip about 50% the amount of downward movement of 
the  maxilla  (see  Figure  74-26,  D).  Mandibular  advancement 
advances  the  soft  tissue  pogonion  approximately  100%. With 
mandibular advancement, the lower lip labrale inferius advances 
approximately  85%  (see  Figure  74-26,  E). As  the  mandible  is 
1060 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
and immediately before surgery. Use the same basic approach 
to STO construction as described for the initial STO. Correla-
tion of  the model  surgery  to  the final STO prediction  tracing 
should provide an accurate surgical guide.
Definitive Treatment Plan
Formulate the definitive treatment plan based on the patient’s 
concerns,  clinical  evaluation,  radiographic  analysis,  dental 
moved  posteriorly,  the  soft  tissue  pogonion  moves  backward 
approximately  90%  of  the  amount  of  bony  movement  (see 
Figure 74-26, F). For chin augmentations, osseous or alloplastic, 
soft tissues advance approximately 80% to 85% the amount of 
AP hard tissue augmentation (see Figure 74-26, G). The vertical 
lengthening of the chin causes about 100% of soft tissue vertical 
change at the menton. Posterior movement of the chin results 
in  about  90%  posterior  movement  of  the  soft  tissues  (see  
Figure 74-26, H). Vertical  reduction of  the chin with a wedge 
ostectomy  and  moving  the  inferior  border  of  the  mandible 
superiorly results in about a 90% vertical soft tissue change (see 
Figure 74-26, I).
Final Surgical Treatment Objective
Perform the final STO on a lateral cephalometric tracing after 
active pre-surgical orthodontic  treatment has been completed 
FIG 74-21 A, The vertical position of the maxillary central inci-
sors is selected, and a horizontal line is drawn to mark that 
position. The anteroposterior (AP) position of the labial surfaces 
of the maxillary central incisors is determined by placing a short 
vertical line 4 mm anterior to the normal maxillary depth. The 
occlusal plane angle (normal 8 ±4 degrees) is selected based 
on functional and esthetic goals. B, The anterior maxillary 
segment is aligned and positioned by placing the incisal tips of 
the maxillary central incisors on the horizontal reference line. 
The vertical surface should be placed against the anterior refer-
ence line and point A on the normal maxillary depth line. The 
anterior maxilla and the surgical reference lines then are traced. 
A
B
FIG 74-22 The mandible is positioned into the best fit in refer-
ence to the maxillary incisors and the occlusal plane angle refer-
ence line. The distal mandibular dental segment and surgical 
reference lines then are traced. 
FIG 74-23 The proximal segment is rotated until the buccal 
horizontal surgical reference lines contact each other. The proxi-
mal segment and surgical reference lines then are traced. 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1061
model evaluation,  initial STO, and other relevant studies. The 
general sequencing of treatment is described next.
Dental and Periodontal Treatment
Perform  any  indicated  periodontal  or  general  dental  mainte-
nance, prevention, or restoration before orthodontic and surgi-
cal  intervention.  The  dental  objective  is  to  maintain  as  many 
teeth as possible and to stabilize the periodontium. Place tem-
porary crowns and bridges where necessary for the orthodontic 
and  surgical  phases  of  treatment.  Fabricate  definitive  restora-
tions  and  deliver  them  after  surgery  and  orthodontics  are  
completed. Periodontal management may  include  scaling and 
curettage,  as  well  as  gingival  grafting,  to  provide  adequate 
attached gingiva. Gingival grafting most commonly  is needed 
in the anterior mandible. Adequate attached gingiva and good 
periodontal  health  are  most  important  when  orthodontic 
mechanics will  tip the mandibular anterior teeth forward and 
when  anterior  vestibular  incisions  are  necessary  to  perform 
genioplasty,  subapical  osteotomies,  or  anterior  body  osteoto-
mies. Inadequate attached gingiva likely will result in periodon-
tal stripping and loss of supportive bone.
Extractions
Extractions are sometimes necessary to correct for arch length 
and dental width discrepancies. Premolars are the most common 
teeth extracted, usually related to excessive crowding or overan-
gulated incisors. Ideally, third molars should be removed at least 
9  to  12  months  before  mandibular  osteotomies,  particularly 
when traditional sagittal split surgical techniques are planned. 
Early  removal allows  the extraction sites  to heal properly and 
provides  stable  bony  interfaces  for  the  osteotomized  bony 
margins. The presence of the third molars significantly weakens 
proximal and distal segments and may increase the risk of unfa-
vorable splits or mandibular fractures with the traditional sag-
gital split design. Use of the inferior border osteotomy technique 
FIG 74-24 The posterior segment of the maxilla is positioned 
and integrated with the best fit into the mandible. The surgical 
reference lines are traced appropriately. 
FIG 74-25 A, The NB line is drawn to determine the anteropos-
terior (AP) position of the chin. An ideal relationship is when the 
labial surfaces of the mandibular central incisors and the chin 
are 4 ±2 mm anterior to the NB line. The vertical height of the 
mandible, as measured from the mandibular central incisor tips 
to hard tissue menton, should equal twice the upper lip length 
for optimal facial balance. B, Indicated chin alterations are 
made, the soft tissues are drawn, and dento-osseous changes 
are recorded. 
4
9
6
5
6
3
5 6
5
3
3
21
A
B
1062 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-26 A, The upper lip moves forward approximately 80% 
to 100% the amount of maxillary advancement, depending on 
the soft tissue management, such as using the alar base cinch 
suture and V-Y closure to increase the post-surgery thickness 
of the upper lip, and the nasal tip elevates approximately 35%. 
B, When the maxilla is moved posteriorly, the upper lip retracts 
about 50% of the maxillary movement. C, With superior repo-
sitioning of the maxilla, the upper lip shortens vertically 10% to 
40% the amount of vertical movement, depending on soft 
tissue management. D, The upper lip lengthens approximately 
50% the amount of downward movement of the maxilla. 
E, With mandibular advancement, the soft tissue pogonion 
advances approximately the same distance as the anteroposte-
rior (AP) bony movement. The lower lip advances about 85%. 
F, As the mandible is moved posteriorly, the soft tissue pogo-
nion moves posteriorly approximately 90% the amount of bony 
movement. The upper lip moves posteriorly approximately 20% 
the amount of mandibular posterior movement. G, Osseous or 
alloplastic chin augmentation produces approximately an 80% 
to 85% soft tissue advancement. H, As the chin is set posteri-
orly, the soft tissues change about 90% the amount of AP 
movement.I, As the osseous chin is moved superiorly, the soft 
tissue change is about 90% of the vertical bony movement. 
B
35%
80% 50%
50%
20%
20%
30%
10% - 40%
80%
80%100%
100%
85%
90%
90%
20%
90%
90%
90%
A
C D
E F G
H I
allows safe removal of the mandibular third molars at the time 
of sagittal split osteotomy.20 Maxillary third molars also may be 
removed  at  the  same  time  as  the  maxillary  osteotomies.  If 
removing  maxillary  third  molars  during  orthognathic  proce-
dures, preferably remove them after mobilization of the maxilla 
to minimize  the risk of unfavorable  fracture  in  the  tuberosity 
region. If the maxillary third molars are removed before orthog-
nathic  surgery,  remove  them  9  to  12  months  before  to  allow 
adequate healing and to optimize the vertical bony support in 
this region.
Virtual Surgical Planning
VSP uses computer technology to simulate the planned surgical 
procedures.  Over  the  past  decade,  computer-aided  surgical 
simulation  (CASS)  technology  has  been  integrated  to  many 
maxillofacial  surgical  applications,  including  dentofacial  
deformities,  congenital  deformities,  defects  after  tumor  abla-
tion,  posttraumatic  defects,  reconstruction  of  cranial  defects, 
and reconstruction of the TMJ.22-26 CASS technology applied to 
orthognathic  surgery  can  improve  surgical  accuracy,  provide 
intermediate  and  final  surgical  splints,  and  decrease  the  sur-
geon’s  time  input  for pre-surgical preparation compared with 
traditional  methods  of  case  preparation.  Data  for  VSP  in 
orthognathic surgery cases can be obtained from high quality 
cone  beam  scans,  but  better  quality  simulation  and  accuracy 
can be acquired from medical grade CT scans of the jaws with 
1-mm overlapping cuts.
For  orthognathic  surgery  cases,  the  original  cephalometric 
tracing, clinical evaluation, and prediction tracing are used in 
conjunction  with  computer-generated  skeletal,  occlusion,  and 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1063
computer model are placed into the final predetermined posi-
tion  using  the  planned  measurements  for  correction  of  the 
maxillary  and  mandibular AP  and  vertical  positions,  occlusal 
plane angulation, pitch, yaw, and roll based on the clinical eval-
uation,  prediction  tracing,  and  computer  model  (see  Figure 
74-27, B). Computer  simulation eliminates  errors  that  can be 
soft tissue simulation of the patient’s structures to configure the 
surgical movements. Dental models can be scanned and incor-
porated  into  the  computer  model  to  accurately  duplicate  the 
dental  anatomy  (see  Dental  Model  Preparation  later  in  this 
chapter). Working with a computer engineer at one of the VSP 
companies (Figure 74-27, A), the mandible and maxilla on the 
FIG 74-27 A, Virtual surgical planning (VSP) set-up on the computer with maxilla and mandible 
in the original position and dental models scanned and incorporated into the computer model. 
B, Maxilla and mandible in final post-surgical position. C, Because mandibular surgery will be 
done first in this case, the mandible is retained in its final position, the maxilla is placed into its 
original position, and the intermediate splint is constructed. If the surgeon prefers to operate on 
the maxilla first, then the maxilla is maintained in the final position and the mandible is placed 
back into its original position for intermediate splint construction. 
A
B
C
1064 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
are done) are sent to the VSP company for scanning and simula-
tion  into  the  computer  model.  Because  the  authors  routinely 
perform  the  mandibular  osteotomies  first,  the  unsegmented 
maxillary model is simulated into the original maxillary posi-
tion and the mandible model is simulated into its final position. 
The intermediate splint is constructed (Figure 74-28). Then the 
segmented  maxillary  model  is  simulated  into  the  computer 
model  with  the  maxilla  in  its  final  position,  the  maxilla  and 
mandible  are  placed  into  the  best  occlusal  fit,  and  the  palatal 
splint is fabricated, or an occlusal splint if the surgeon prefers. 
The  dental  models,  splints,  and  images  of  the  computer-
simulated surgery are sent to the surgeon for  implementation 
during the actual surgery.
Combined Temporomandibular Joint Total Joint Replacement 
With Concomitant Orthognathic Surgery
TMJ disorders or pathology and dentofacial deformities com-
monly coexist. The TMJ pathology may be the causative factor 
of the jaw deformity, develop as a result of the jaw deformity, 
or  the  two  entities  may  develop  independently  of  each  other. 
The  most  common TMJ  pathologies  that  can adversely  affect 
jaw  position,  occlusion,  and  orthognathic  surgical  outcomes 
include  (1)  articular  disc  dislocation,  (2)  adolescent  internal 
condylar resorption (AICR), (3) reactive arthritis, (4) condylar 
hyperplasia,  (5)  ankylosis,  (6)  congenital  deformation  or 
absence  of  the  TMJ,  (7)  connective  tissue  and  autoimmune 
diseases, (8) trauma, and (9) other end-stage TMJ pathologies. 
These  TMJ  conditions  are  often  associated  with  dentofacial 
deformities,  malocclusion,  TMJ  pain,  headaches,  myofascial 
pain,  TMJ  and  jaw  functional  impairment,  ear  symptoms,  
sleep  apnea,  and  so  on.  Patients  with  these  conditions  may 
benefit  from  corrective  surgical  intervention,  including  TMJ 
and  orthognathic  surgery.  Some  of  the  aforementioned  TMJ 
pathologies  may  have  the  best  outcome  prognosis  using  
patient-fitted  (custom-made)  total  joint  prostheses  for  TMJ 
reconstruction.25,26
Many  clinicians  choose  to  ignore  the  TMJ  pathology  and 
perform  only  orthognathic  surgery  for  these  types  of  cases,  
but  this  treatment  philosophy  can  result  in  continuation  or 
created with the traditional model surgery techniques for repo-
sitioning  the  maxilla  and  mandible  on  articulator-mounted 
models that rely on the operator’s manual dexterity and three-
dimensional perspective  that play a  critical  role  in  setting  the 
mandible and maxilla into their proper and final position. This 
operator factor can predispose the planning process to signifi-
cant error.
Once  the  final  position  of  the  maxilla  and  mandible  are 
established, the intermediate splint can be constructed by one 
of the following methods:
1.  Many  patients  requiring  orthognathic  surgery  will  benefit 
from  counterclockwise  rotation  of  the  maxillomandibular 
complex, which requires the development of posterior open 
bites  on  the  model  for  construction  of  the  intermediate 
splint when the mandible is repositioned first. In this situa-
tion, the maxilla is returned to its original position while the 
mandible  is  maintained  in  its  final  position  (see  Figure 
74-27, C),  and  the computer-generated  intermediate  splint 
is printed out. The final splint (a palatal splint is used by the 
authors)  is  printed  out  with  the  maxilla  and  mandible  in 
their final position.
2.  When it is preferred to reposition the maxilla first, the man-
dible is returned to its original position while the maxilla is 
maintained in its final position and the palatal splint, if the 
maxilla is segmented, and the intermediate splint are printed 
out. The final splint is generated with the maxilla and man-
dible  in the final position. The splints are produced by the 
VSP company.
Dental Model Preparation
Approximately 2 weeks before surgery, the final dental models 
are produced, including two maxillary models if the maxilla is 
to be segmented or dental equilibration is required. One of the 
maxillary models is segmented if indicated, dental equilibration 
is performed, and the segments are placed in the best occlusion 
fit with the mandibulardentition and maxillary segments fixed 
to each other. The dental models do not require mounting on 
an articulator. The three or four models (two maxillary and one 
mandibular, or two mandibular models if dental equilibrations 
FIG 74-28 A and B, The intermediate splint is constructed from the virtual surgical planning (VSP) 
model. The final palatal splint is also constructed from the VSP model with the same design as 
seen in Figures 75-18 and 75-19. 
A B
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1065
1. Computed tomography (CT) scan including the entire mandible, 
maxilla, and temporomandibular joints (TMJs)
2. Fabrication of stereolithic model with the mandible separated
3. Surgeon positions the mandible in its final position and fixates it
4. Remove condyles and recontour the lateral aspect of the rami and 
fossae if indicated
5. Model sent to TMJ Concepts for prostheses design, blueprint, and 
wax-up
6. Approval of total joint prostheses blueprint and wax-up by the surgeon
7. Manufacture of custom-fitted total joint prostheses
8. Prostheses sent to hospital for surgical implantation
BOX 74-1 Protocol for Traditional 
Concomitant Orthognathic Surgery
1. Acquisition of dental models
2. Mounting maxillary and mandibular dental models on an articulator
3. Reposition the mandibular dental model, duplicating the positional 
changes acquired on the stereolithic model
4. Fabrication of intermediate splint
5. Reposition maxillary dental model with segmentation if indicated
6. Construction of palatal splint
7. Ready for surgery
BOX 74-2 Steps in Traditional 
Orthognathic Surgery, Intermediate, and 
Palatal Splint Fabrication for Concomitant 
Orthognathic Surgery
exacerbation of the pre-surgery TMJ pathology and reproduce 
the original deformity with worsening occlusion, jaw dysfunc-
tion,  facial  imbalance,  and  pain.  Clinicians  who  address  the 
dentofacial deformities and TMJ pathologies that require total 
joint  prostheses  can  perform  the  surgery  in  one  stage  or  two 
separate stages. The two-stage approach requires the patient to 
undergo  two  separate  operations  and  anesthesia,  significantly 
prolonging  the  overall  treatment.  However,  performing  con-
comitant TMJ and orthognathic surgery (concomitant orthog-
nathic  surgery  [CTOS])  in  these  cases  significantly  decreases 
treatment  time  and  provides  better  outcomes,  but  it  requires 
careful treatment planning and surgical proficiency in the two 
surgical  areas. Using  traditional model  surgery and  treatment 
planning techniques exposes the outcome to its own subset of 
error margin. As a result, CTOS can provide improved accuracy 
and saves considerable preparation time, but it requires experi-
ence and expertise in orthognathic and TMJ surgery.
VSP  is  a  significant  improvement  for  the  construction  of 
total joint prostheses that also required CTOS. Treatment plan-
ning for CTOS cases is based on cephalometric analysis, predic-
tion  tracing,  clinical  evaluation,  and  dental  models,  which 
provide  the  template  for  movements  of  the  upper  and  lower 
jaws  to  establish  optimal  treatment  outcome  in  relation  to  
function, facial harmony, occlusion, and oropharyngeal airway 
dimensions. For patients who  require  total  joint prostheses,  a 
medical grade CT scan with 1-mm overlapping cuts is acquired 
of the maxillofacial region that includes the TMJs, maxilla, and 
mandible. The surgeon has two options for model preparation 
to aid in the construction of patient-fitted total joint prostheses 
using the TMJ Concepts system (Ventura, CA).
Protocol for Traditional Concomitant 
Orthognathic Surgery
Treatment  planning  for  CTOS  cases  is  based  on  prediction 
tracing, clinical evaluation, and dental models, which provide 
the  template  for  movements  of  the  upper  and  lower  jaws  to 
establish  optimal  treatment  outcome  in  relation  to  function, 
facial  harmony,  occlusion,  and  oropharyngeal  airway  dimen-
sions (Boxes 74-1 and 74-2). For patients who require total joint 
prostheses, a CT scan is acquired of the maxillofacial region that 
includes the TMJs, maxilla, and mandible with 1-mm overlap-
ping  cuts.  Using  these  CT  scan  data,  a  stereolithic  model  is 
fabricated,  with  the  mandible  as  a  separate  piece.  Using  the 
original  cephalometric  tracing  and  prediction  tracing  (Figure 
74-29, A), the mandible on the stereolithic model is placed into 
its future predetermined position using the planned measure-
ments for correction of mandibular AP and vertical positions, 
occlusal plane alteration, pitch, yaw, and roll (see Figure 74-29, 
B).  The  mandible  is  stabilized  to  the  maxilla  with  quick-cure 
acrylic. Many patients with TMJ pathology requiring CTOS will 
benefit from counterclockwise rotation of the maxillomandibu-
lar complex. Repositioning the mandible into its final position 
requires the development of posterior open bites on the model 
(see Figure 74-29, B). Because the mandibular position on the 
stereolithic  models  is  established  using  hands-on  measure-
ments, the operator’s manual dexterity and three-dimensional 
perspective  play  a  critical  role  in  setting  the  mandible  in  its 
proper and final position. This step can predispose the planning 
process to a certain margin of error.
The next step requires condylectomies as well as preparation 
of the lateral aspect of the rami and fossae (Figure 74-30, A and 
B) for fabrication of the patient-fitted total joint prostheses. The 
goal of this step is to recontour the lateral ramus to a relatively 
flat surface  in the area where the mandibular component will 
be placed. The fossa requires recontouring only  if heterotopic 
bone or unusual anatomy is present. The recontouring areas are 
marked  in  red  for  duplication  of  bone  removal  at  surgery. 
Because most patients with TMJ problems requiring CTOS can 
benefit from counterclockwise rotation of the maxillomandibu-
lar complex, the stereolithic model will likely be set with poste-
rior open bites, because the maxilla is maintained in its original 
position.
Once the stereolithic model is finalized, the model is sent to 
TMJ Concepts to perform the design, blueprint, and wax-up of 
the  custom-fitted  total  joint  prostheses  (see  Figure  74-30,  C), 
with  the  design  and  wax-up  sent  to  the  surgeon  for  approval 
before  manufacture  of  the  prostheses.  The  period  from  CT 
acquisition  to  the  manufacturer’s  completion  of  the  patient-
fitted prostheses is approximately 8 weeks. Prior to surgery, the 
surgical  procedures  are  performed  on  articulator-mounted 
dental models. The mandible is repositioned on the articulator, 
duplicating  the  movements  performed  on  the  stereolithic 
model, and the  intermediate splint  is constructed. The maxil-
lary model is repositioned, segmented if indicated, and placed 
into  the  maximal  occlusal  fit.  Then,  the  palatal  splint  is  con-
structed (see Figures 74-18 and 74-19).
Protocol for Concomitant Orthognathic Surgery Using 
Computer-Aided Surgical Simulation
For  CTOS  cases,  the  orthognathic  surgery  is  planned  using 
CASS  technology  and  moving  the  maxilla  and  mandible  into 
their  final  position  in  a  computer-simulated  environment 
(Figure  74-31,  A  and  C).  Using  the  computer  simulation,  the 
AP and vertical positions, occlusal plane alteration, pitch, yaw, 
1066 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-29 A, Measurement of the cephalometric prediction tracing for the amount of open 
bite produced at the second molar after counterclockwise rotation of the mandible into its final 
position. B, Duplication of the measurement obtained from the prediction tracing to the final 
mandibular position on the stereolithic model and fixating the mandible to the maxilla with meth-
ylmethacrylate. (From Movahed R, TeschkeM, Wolford LM: Protocol for concomitant temporo-
mandibular joint custom-fitted total joint reconstruction and orthognathic surgery utilizing 
computer-assisted surgical simulation. J Oral Maxillofac Surg 71(12):2123-2129, 2013.)
A B
FIG 74-30 A, Marking the condylectomy osteotomy and the irregularities of the fossa. B, The 
stereolithic model after condylectomy and recontouring of the fossae and rami (marked in red). 
C, Stereolithic model with prostheses wax-up for approval by the surgeon. (From Movahed R, 
Teschke M, Wolford LM: Protocol for concomitant temporomandibular joint custom-fitted total 
joint reconstruction and orthognathic surgery utilizing computer-assisted surgical simulation. 
J Oral Maxillofac Surg 71(12):2123-2129, 2013.)
A B C
and roll are accurately finalized  for  the maxilla and mandible 
based on clinical evaluation, dental models, prediction tracing, 
and computer-simulation analysis. Segmentation of the maxilla 
can be simulated (Box 74-3).
Using  Digital  Imaging  and  Communications  in  Medicine 
(DICOM)  data,  the  stereolithic  model  is  produced  with  the 
maxilla  and  mandible  in  the  final  position  and  provided  to  
the  surgeon  for  removal  of  the  condyle  and  recontouring  of  
the  lateral rami and fossae  if  indicated (Figure 74-32, A). The 
stereolithic  model  is  sent  to  TMJ  Concepts  for  the  design,  
blueprint, and wax-up of the prostheses. Using the Internet, the 
design  is  sent  to  the  surgeon  for approval. Then,  the custom-
fitted total joint prostheses are manufactured (see Figure 74-32, 
B). It takes approximately 8 weeks to manufacture the total joint 
patient-fitted prostheses.
Approximately  2  weeks  before  surgery,  final  dental  models 
are acquired including two maxillary models if the maxilla is to 
be  segmented  or  dental  equilibration  is  required.  One  of  the 
maxillary models is segmented if indicated, dental equilibration 
is performed, and the segments are placed in the best occlusion 
fit with the mandibular dentition and maxillary segments fixed 
to each other. The dental models do not require mounting on 
an articulator. The three or four models (two maxillary and one 
mandibular,  or  two  mandibular  models  if  equilibrations  are 
done) are physically sent to the VSP company for scanning and 
simulation  into  the  computer  model.  Alternatively,  with  an 
i-CAT machine,  the models can be  scanned and digitally  sent 
to the VSP company. Because the authors routinely perform the 
TMJ  reconstruction  and  mandibular  advancement  with  the 
TMJ  Concepts  total  joint  prosthesis  first,  the  unsegmented 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1067
FIG 74-31 Staged computer-aided surgical simulation surgical report. A, Simulated preoperative 
position of the maxilla and mandible. B, The maxilla and mandible in the simulated intermediate 
position, with the maxilla in its original position, but mandible in its final position with the 
mandibular surgery performed first for fabrication of the intermediate splint. C, The final 
position of maxilla and mandible, after advancement of mandible and segmental osteotomy of 
the maxilla, for the production of a palatal splint. (From Movahed R, Teschke M, Wolford LM: 
Protocol for concomitant temporomandibular joint custom-fitted total joint reconstruction and 
orthognathic surgery utilizing computer-assisted surgical simulation. J Oral Maxillofac Surg 
71(12):2123-2129, 2013.)
C
B
A
1068 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-32 A, Stereolithic model fabricated after simulated maxillary and mandibular advance-
ment to the final position. Condylectomy and recontouring of the lateral rami and fossae were 
performed and sent to TMJ Concepts for construction of the prostheses. B, Constructed patient-
fitted temporomandibular joint (TMJ) prosthesis using the computer-aided surgical simulation 
fabricated stereolithic model. (From Movahed R, Teschke M, Wolford LM: Protocol for concomi-
tant temporomandibular joint custom-fitted total joint reconstruction and orthognathic surgery 
utilizing computer-assisted surgical simulation. J Oral Maxillofac Surg 71(12):2123-2129, 2013.)
A B
1. Computed tomography (CT) scan of entire mandible, maxilla, and 
temporomandibular joints (TMJs) (1-mm overlapping cuts)
2. Processing of Digital Imaging and Communications in Medicine 
(DICOM) data to create a computer model in computer-aided 
surgical simulation (CASS) environment
3. Correction of dentofacial deformity, including final positioning of the 
maxilla and mandible, with computer-simulated surgery
4. Stereolithic model constructed with jaws in final position and sent 
to surgeon for condylectomy and rami and fossae recontouring if 
indicated
5. Model sent to TMJ Concepts for prostheses design, blueprint, and 
wax-up
6. Surgeon evaluation and design approval using the Internet
7. TMJ prostheses manufactured and sent to hospital for surgical 
implantation
8. Two weeks before surgery, acquisition of final dental models (two 
maxillary, one or two mandibular models if dental equilibrations are 
required); one maxillary model is segmented and models equili-
brated if indicated to maximize the occlusal fit; models sent to the 
virtual surgical planning (VSP) company
9. Models incorporated into computer-simulated surgery for construc-
tion of intermediate and final palatal splints
10. Models, splints, and printouts of computer-simulated surgery sent 
to surgeon
BOX 74-3 Protocol of Concomitant 
Orthognathic Surgery Using Computer-Aided 
Surgical Simulation
maxillary model is simulated into the original maxillary posi-
tion and the mandible is maintained in the final position. The 
intermediate  splint  is  constructed  (see  Figures  74-28  and  74-
31). Then the segmented maxillary model is simulated into the 
computer model in its final position, with the best occlusal fit 
with the mandibular occlusion, and the palatal splint  is  fabri-
cated or an occlusal splint is made if the surgeon prefers. The 
dental models,  splints, and  images of  the computer-simulated 
surgery  are  sent  to  the  surgeon  for  implementation  during 
surgery.
Using CASS technology for CTOS cases eliminates the ‘‘tra-
ditional’’ steps requiring the surgeon to manually set the man-
dible into its new final position on the stereolithic model, thus 
saving time and improving surgical accuracy. Although dental 
model surgery is necessary only if the maxilla requires segmen-
tation, the models do not require mounting on an articulator. 
This saves considerable  time by eliminating the time required 
to  mount  the  models,  prepare  the  model  bases  for  model 
surgery,  reposition  the  mandible,  construct  the  intermediate 
occlusal  splint,  and  make  the  final  palatal  splint.  With  CASS 
technology, the splints are manufactured by the VSP company.
Surgery
The surgical procedures used to correct existing musculoskel-
etal deformities should provide optimal functional and esthetic 
results with good stability. Take new records before surgery, and 
reevaluate the patient to determine the progress and readiness 
for surgery. Perform a new STO to determine the final position 
of  the  jaws  and  to  predict  the  resultant  profile.  Use  VSP  or 
traditional pre-surgical preparation.25,26 For  traditional prepa-
ration  in  double  jaw  surgery,  perform  simulated  surgery  on  
the articulator–mounted dental models to duplicate the dento-
osseous  movements  determined  from  the  STO  and  make  the 
intermediate and final splints. Alternatively, use the CASS tech-
nology for surgical preparation.
The following is the preferred surgical sequencing:
1.  TMJ surgery if indicated
2.  Mandibular ramus sagittal split osteotomies
3.  Removal of mandibular third molars
4.  Subapical and/or body osteotomies
5.  Application of rigid fixation to mandible
6.  Maxillary osteotomiesand mobilization
7.  Removal of maxillary third molars
8.  Turbinectomies/nasal septoplasties
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1069
to 85% of the amount of bony augmentation (see Figure 74-26, 
G).  Over  time,  anterior  bone  resorption  can  occur  with  an 
osseous  result of 80% compared with  the original  amount of 
advancement. Soft tissue also may regress posteriorly.
Anteroposterior reduction. Optimal  soft  tissue  change  is 
achieved  by  performing  a  horizontal  sliding  osteotomy  and 
moving the chin and attached soft tissues posteriorly. The chin 
usually appears wider after this procedure, and the labiomental 
fold decreases. Soft tissue change, if soft tissue remains attached 
to the anterior and inferior aspect of  the chin,  is usually 90% 
of the AP bony reduction. Shaving of the anterior aspect of the 
bony chin may result in only 20% to 30% posterior movement 
of  the  soft  tissue  in  relation  to  the amount of bone removed. 
Take care to ensure the soft tissues “follow” the hard tissue. Not 
infrequently,  failure  to  do  so  leaves  a  mobile  soft  tissue  mass 
that  may  be  pulled  inferiorly  by  the  mentalis  to  produce  an 
unattractive ptosis of the lower lip and chin.
Vertical augmentation (down graft). Vertical  augmenta-
tion is accomplished best with a horizontal osteotomy and infe-
rior repositioning of the chin segment. This technique usually 
requires bone or synthetic bone grafting. Soft tissue change is 
approximately 100% of the osseous change.
Vertical reduction. The most predictable vertical reduction 
is  with  a  wedge  resection  and  rotation  of  the  inferior  chin 
segment  superiorly. When  soft  tissue  remains  attached  to  the 
inferior border, the soft tissue change is approximately 90% of 
the vertical osseous change. If the inferior border is resected and 
removed, then the vertical soft tissue change is only 25% to 30% 
of the amount of bone removed.
Transverse repositioning. Transverse repositioning is used 
to  correct  chin  asymmetry.  A  horizontal  osteotomy  is  per-
formed, and the chin is shifted to the determined position and 
stabilized.
Lateral augmentation. By splitting the chin segment in the 
midline, the segments can be expanded and stabilized. If a large 
expansion is planned, the midline defect may require bone or 
synthetic bone grafting. Narrowing of the chin can be accom-
plished by rotating the segments medially, but the effectiveness 
of this technique is limited.
Age for osseous genioplasty. Perform  osseous  genioplasty 
after  12  years  of  age  to  allow  for  eruption  of  the  permanent 
mandibular canines and premolars.
Alloplastic augmentations. Various synthetic materials have 
been  used  to  augment  the  chin  (see  Figure  74-33,  B).27  Rigid 
stabilization of implants is critical, because mobility may result 
in malposition, bone resorption, and infection. Most infections 
of chin implants occur when there is improper fixation or inad-
equate  soft  tissue  closure.  The  following  recommended  tech-
nique is safe and provides good long-term stability:
1.  Perform  the  chin  implant  as  the  last  step,  after  all  other 
orthognathic  procedures  are  completed  and  the  associated 
incisions are closed.
2.  After  exposure  and  preparation  of  the  implant  area,  thor-
oughly irrigate with sterile saline.
3.  Change gloves and wash off glove powder before handling 
the implant.
4.  Stabilize the implant to the mandible to eliminate mobility 
and migration by using bone screws, plates, or intraosseous 
wiring.
5.  Irrigate  the  surgical area  thoroughly and close  the  incision 
in  two  layers with reapproximation of  the mentalis muscle 
layer and tight mucosal closure.
9.  Maxillary  segmentation, application of  rigid fixation, and 
appropriate bone grafting
10.  Adjunctive  procedures;  genioplasty,  facial  augmentation, 
rhinoplasty, and so on
This  sequencing  helps  achieve  optimal  outcomes,  whether 
performed  in  one  or  more  operations.  With  the  use  of  rigid 
fixation, maxillomandibular fixation is rarely needed.
Definitive Periodontal and General Dental Management
Definitive periodontal  treatment,  such as  esthetic periodontal 
surgery and mucoperiosteal flap procedures, may be performed 
at this time. Lastly, definitive restorations and prosthetic tooth 
replacement complete the treatment.
Surgical Procedures
Many  surgical  procedures  are  available  to  correct  dentofacial 
deformities. Oral and maxillofacial surgeons should have expe-
rience with these procedures and a thorough understanding of 
reasonable treatment goals in order to develop a plan that pro-
vides optimal functional and esthetic results. The surgeon must 
be aware of the potential risks and complications that can occur 
with  each  of  these  procedures.  This  knowledge  enables  the 
surgeon to develop an optimal treatment plan and alternative 
treatments according to his or her skill level. The surgeon should 
communicate to the patient the existing problems, the magni-
tude of these problems, the recommended treatment, alternative 
treatment options, and the potential risks and complications.
Genioplasty procedures. Genioplasty  procedures  can  alter 
the position of the chin in all three planes of space. Chin posi-
tion most commonly is changed by use of a sliding osteotomy 
or by the addition of an alloplastic implant.
Osseous procedures. When  the  bony  chin  is  to  be  reposi-
tioned, a soft tissue pedicle must be maintained to ensure viabil-
ity  to  the  osteotomized  segment.  The  traditional  horizontal 
osteotomy  (Figure  74-33,  A)  or  the  tenon  and  mortise  tech-
nique can be used. Stabilization can be achieved by wiring, bone 
screws, and/or bone plates.
Anteroposterior augmentation. The  usual  limiting  factor 
for  chin  advancement  is  the AP  dimension  of  the  symphysis, 
unless the osteotomized segment is tiered surgically. If the chin 
is  narrow  transversely,  advancement  tends  to  make  the  face 
appear more tapered. Soft tissue change is approximately 80% 
FIG 74-33 A, An osseous genioplasty can be used to augment 
the chin, move it posteriorly, alter its vertical position, or change 
the transverse position of the chin. B, Alloplastic implants can 
be used to augment the chin anteriorly. They are less effective 
for vertical augmentation. 
A B
1070 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
A relative contraindication is the necessity for multiple single- 
or two-tooth segments because of a high incidence of tooth and 
bone loss.
If a tenon and mortise technique is used and the segment is 
to  be  moved  posteriorly,  base  the  tenon  on  the  mobilized 
segment.28  When  the  segment  is  being  moved  forward,  base 
the tenon on the proximal mandibular segment. Bone screws, 
interosseous wiring, or bone plates can be used to stabilize the 
bone segments. Soft  tissue closure  is achieved by suturing the 
muscle  layer  first  to  resuspend  the  lower  lip  and  then  a  tight 
mucosal closure.
Posterior mandibular subapical osteotomy. Posterior 
mandibular  subapical  osteotomy  is  a  difficult  procedure  that 
may result in a tenuous blood supply to the mobilized segment. 
Usually the inferior alveolar neurovascular bundle is detached 
from the segment so that the vascular supply is primarily from 
lingual periosteum and muscle. Morbidity to the inferior alveo-
lar nerve is high. The procedure is technically more difficult in 
patients with high mandibular plane angles and decreased pos-
terior vertical mandibular height.
Total mandibular subapical osteotomy. Total  mandibular 
subapical osteotomy is also a technically difficult procedure, but 
Although many alloplastic materials have been used for chin 
augmentation,  only  one  is  currently  recommended:  Medpor 
(Porex,  Newnan,  GA)  is  a  porous  polyethylene  preformedimplant with a selection of sizes and designs.
Alloplastic  augmentation  genioplasty  may  be  performed 
after eruption of the mandibular anterior teeth.
Complications. Several potential complications are associ-
ated with osseous and alloplastic augmentation:
•  Loss of osteotomized bone segment
•  Bone resorption
•  Infection
•  Displacement/malalignment
•  Paresthesia/anesthesia of lower lip and chin
•  Lower lip ptosis
•  Mentalis muscle dysfunction
•  Unsatisfactory esthetic outcome
Loss of the osteotomized bone segment may occur following 
avascular necrosis. Avascular necrosis usually occurs because of 
loss of tissue attachment or infection. Loss of the segment may 
require further alloplastic or bone graft reconstruction. A large 
amount of bone resorption can be expected if a free bone graft 
is used to augment the chin or if the soft tissue pedicle to the 
mobilized chin segment is stripped excessively. Pedicled osseous 
genioplasties usually undergo anterior bone resorption of about 
10% to 20%. Infection most commonly is caused by avascular 
necrosis, contamination, and wound breakdown. Displacement 
of the alloplast may occur following trauma or inadequate sta-
bilization. This may require additional surgery to restabilize the 
implant.  Lower  lip  ptosis  may  be  caused  by  inadequate  posi-
tioning,  resuspension,  or  stabilization  of  the  mentalis  muscle 
and associated  soft  tissues. Normally, when relaxed,  the  lower 
lip should be level with the lower incisor edges. Correction of 
lower lip ptosis requires repositioning and resuspension of the 
mentalis muscles. Anesthesia or paresthesia of the lower lip and 
chin  may  result  from  trauma  to  the  inferior  alveolar  and/or 
mental nerve branches from incision design, dissection, retrac-
tion,  or  direct  injury  when  performing  osteotomies.  Nerve 
injury  may  be  avoided  by  careful  incision  placement,  careful 
dissection,  minimal  nerve  retraction,  and  carefully  planned 
bone cuts. If nerve transection is directly visualized, immediate 
repair is indicated.
Mandibular subapical procedures. These  procedures  are 
designed to alter portions of the mandibular dental alveolus and 
can  be  divided  into  three  types:  anterior,  posterior,  and  total 
subapical osteotomies.
Anterior mandibular subapical osteotomy. Osteotomy 
design  involves  vertical  interdental  osteotomies  joined  by  a 
horizontal  osteotomy  at  least  5 mm  below  the  apices  of  the 
associated teeth (Figure 74-34). A horizontal vestibular incision 
is used for access. The vascularity to the mobilized segment is 
maintained  by  the  lingual  soft  tissue  pedicle.  Indications  for 
anterior mandibular  subapical osteotomy  include  leveling  the 
occlusal  plane,  changing  the  AP  position  of  the  mandibular 
anterior teeth, correcting asymmetries, and changing the axial 
angulation of the mandibular anterior teeth.
Identify  contraindications  to  these  procedures  before  pre-
surgical orthodontic treatment. Tooth roots too close together 
at  the  interdental  osteotomy  site  may  cause  root  amputation, 
ankylosis, periodontal defects, or loss of teeth and bone. Severe 
periodontal problems also may result from excessive removal of 
interdental bone. Major changes in vertical position may worsen 
pre-existing periodontal problems in area of vertical osteotomy. 
FIG 74-34 A and B, Vertical interdental osteotomies are per-
formed with a connecting horizontal osteotomy. The horizontal 
osteotomy should be positioned at least 5 mm below the apices 
of the teeth to minimize the risk of dental devitalization. 
A
B
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1071
if performed below the inferior alveolar bundle, the mobilized 
segment maintains a good blood supply. This procedure is com-
plicated  by  the  fact  that  it  most  often  is  indicated  in  patients 
with a low mandibular plane angle. The neurovascular bundle 
sometimes must be dissected free of the mandible before per-
forming  the  osteotomy.  The  risk  of  inferior  alveolar  nerve 
injury  is  high.  Indications  include  a  retruded  dentoalveolus 
with a strong chin and transverse discrepancies with an accen-
tuated curve of occlusion. Although few absolute contraindica-
tions  exist,  there  are  several  relative  contraindications  and 
precautions for this difficult procedure. Decreased anterior and 
posterior mandibular height, for example, increases the techni-
cal difficulty of performing the osteotomy. When the dentoal-
veolus  needs  to  be  advanced  considerably  beyond  the  stable 
chin point, there may be better treatment alternatives.
Age for surgery. Although  no  studies  refer  to  the  vertical 
growth  effects  of  interdental  osteotomies,  it  is  recommended 
that  surgery  be  performed  in  females  after  the  age  of  14  and 
males after the age of 16.
Possible complications. Possible complications include the 
loss of teeth and bone, periodontal defects, lower lip paresthesia/
anesthesia, and pathological fracture. Anesthesia or paresthesia 
of  the  lip,  teeth,  and  gingiva  may  result  from  trauma  of  the 
inferior alveolar or mental neurovascular bundle. This usually 
resolves  in a  few weeks  to  several months.  If  the neurological 
deficit  lasts  longer  than  1  year,  the  prognosis  for  recovery  is 
poor. If the nerve is severed, primary repair gives the best result. 
Teeth and gingiva in subapical segments commonly exhibit an 
extended period of anesthesia or paresthesia.
Mandibular ramus surgery. Mandibular  sagittal  split  ramus 
osteotomy  is  the  most  common  mandibular  orthognathic 
procedure. This osteotomy technique originally was described 
by  Trauner  and  Obwegeser  in  1957.29  The  bilateral  sagittal 
split  ramus  osteotomy  (BSSRO)  can  be  used  for  mandibular 
advancement  or  setback,  control  of  the  occlusion,  and  posi-
tion  of  the  condyle.  The  technique  has  undergone  numerous 
modifications. The most  recent modification maximizes bony 
interface by splitting the mandible at the inferior border, pro-
viding controlled positioning of the proximal segment (Figure 
74-35).20  Even  with  large  advancements,  bone  grafting  rarely 
is  required.  Indications  for  sagittal  split  ramus  osteotomies 
include mandibular advancement,  setback (Figures 74-36 and 
74-37),  and  correction  of  mandibular  asymmetries.  Progna-
thic  mandibular  setback  requires  removal  of  bone  from  both 
the proximal and distal segments, but is the authors’ preferred 
choice of procedure. Contraindications include severe decreased 
posterior  mandibular  body  height,  extremely  thin  medial-
lateral  width  of  ramus,  severe  ramus  hypoplasia,  and  severe  
asymmetries.
The advantages are as follows:
•  Healing is enhanced because of a good bony interface.
•  The surgery can advance or set back  the mandible, correct 
most asymmetries, and alter the occlusal plane.
•  Rigid fixation can be used, eliminating the need for maxil-
lomandibular fixation. Rigid fixation, when properly applied, 
significantly  improves  the  stability  and  predictability  of 
results.  Bone  plates  with  monocortical  screws  (see  Figure 
74-45) or bicortical bone screws can provide good stability.
•  Modifications can maintain the angle of the mandible in the 
original spatial position, even in large advancements.
•  Major muscles of mastication remain in the original spatial 
position.
The disadvantages are as follows:
•  The incidence of nerve damage is increased, although this is 
usually temporary.
•  Unfavorable splits may occur.
•  Surgery must create a  fracture on  the  lingual aspect of  the 
ramus.
•  Severe asymmetries are difficult to correct.
Vertical oblique osteotomy (subcondylar osteotomy). Extra-
oral  or  intraoral  approaches  can  be  used  for  vertical  oblique 
osteotomy (Figure 74-38).
Indications. The  followingare  indications  for  vertical 
oblique osteotomy:
•  Mandibular setback
•  Small movements (unless temporalis, medial pterygoid, and 
masseter muscles are detached from the distal segment)
•  Asymmetries of mandible requiring setback
•  Large movements that may require coronoidectomies
Stabilize segments with intraosseous wiring or rigid fixation 
for the most predictable results. This procedure is designed to 
allow  the  condyle  and  posterior  border  of  the  mandible  to 
remain essentially in their original positions (although there is 
some  rotation  and  torquing  of  the  condylar  head),  while  the 
mandibular ramus and body are moved posteriorly. This pro-
cedure  involves making a vertical cut  from the sigmoid notch 
to the angle of the mandible.
The contraindications are:
•  Large  setbacks  (unless  temporalis,  medial  pterygoid,  and 
masseter muscles are detached from the distal segment)
•  Large advancements
•  Lengthening of the ramus (unless temporalis, medial ptery-
goid,  and  masseter  muscles  are  detached  from  the  distal 
segment)
The advantages are:
•  Technically easy
•  Correction of mandibular prognathism or asymmetries
The disadvantages are as follows:
•  Unless  segments  are  wired  or  rigidly  stabilized,  it  may  be 
difficult to control the position of the condyle. Condylar sag 
may result in anterior open bite postoperatively.
•  Healing time may be increased because of poor bony inter-
face between segments.
•  Rigid  skeletal  fixation  (i.e.,  bone  screws)  is  difficult  to  use 
through  an  intraoral  approach,  so  the  procedure  usually 
requires 4 to 8 weeks of maxillomandibular fixation.
•  The  procedure  may  require  relatively  long-term  interarch 
elastics  to  control occlusion  following  removal of maxillo-
mandibular fixation because of  increased healing time and 
lack of condyle positional control.
Mandibular ramus inverted L osteotomy. Extraoral  and 
intraoral  approaches  are  acceptable  procedures  for  mandibu-
lar  setbacks (Figure 74-39).  Indications  include small or  large 
setbacks,  asymmetries,  mandibular  advancements,  ramus 
lengthening,  presence  of  a  thin  ramus  mediolaterally,  and 
severe  decrease  in  posterior  mandibular  body  height.  Con-
traindications  include  abnormal  posterior  location  of  the 
mandibular  foramina  and  mandibular  advancements  without  
grafting.
The advantages are as follows:
•  Correct mandibular prognathism or asymmetries.
•  Coronoid process and temporalis muscle remain in original 
position.
•  Mandible can be set back a great distance.
1072 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
Age at surgery. Surgery can be performed predictably from 
the age of 12 years and older. With the sagittal split osteotomy, 
it  is  best  to  use  the  procedure  after  the  second  molars  are 
erupted so that they are not injured before eruption.
Mandibular Body Surgery
Mandibular body surgery can be divided into anterior body and 
posterior body surgery. Anterior body surgery refers to osteoto-
mies anterior to the mental foramen, including the symphysis 
area. Posterior body surgery  involves osteotomies around and 
adjacent to the mental foramen area or further posterior in the 
body  (Figure  74-40).  Posterior  body  surgery  requires  specific 
management of the inferior alveolar neurovascular bundle for 
•  Lengthens ramus or advances the mandible when used with 
bone or synthetic bone grafting.
•  Rigid skeletal fixation can be used.
The disadvantages are as follows:
•  Requires  bone  or  synthetic  bone  grafting  for  significant 
ramus lengthening or mandibular advancement.
•  Healing  time may be  increased compared with other  tech-
niques because of poor approximation of the segments when 
grafts are not used.
Effects on growth. Ramus  procedures  have  no  significant 
effect on rate of growth, but alteration of the position and ori-
entation of the proximal segment can alter the vector of subse-
quent mandibular growth.
FIG 74-35 A and B, Mandibular ramus sagittal split osteotomy is the most common technique 
used for mandibular advancement. C, Rigid fixation significantly improves the stability and pre-
dictability of this technique. D, Demonstrated here is the Z-plate that can be used for mandibular 
advancements and setbacks for reliable stability. 
A
B
C
D
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1073
in  dental  ankylosis,  which  could  result  in  deficient  vertical 
growth.
Age for surgery. This surgery is recommended after the age 
of 14 in females and after age 16 in males.
Potential complications for mandibular body surgery
Nonunion or malunion. Nonunion  or  malunion  usually 
results  from a poor bony  interface,  inaccurate position of  the 
bony  segments,  or  inadequate  stabilization  of  the  segments. 
Nonunion  or  malunion  may  necessitate  additional  surgery  to 
reposition  and  stabilize  the  segments  with  or  without  bone 
grafting.
Loss of teeth and bone. The  loss  of  teeth  and  bone  may 
occur  because  of  vascular  compromise,  resulting  in  infection, 
osteomyelitis, or avascular necrosis. Vascular  insufficiency can 
be  devastating  and  may  require  hyperbaric  oxygen  treatment 
and  secondary  procedures  that  restabilize  or  reconstruct  the 
bone segments.
Infections. Infection or osteomyelitis may require antibiot-
ics  and  débridement.  Infection  is  rare  unless  there  is  major 
damage done to the bone, teeth, and soft tissues during surgery. 
Hyperbaric oxygen therapy may be required as well as second-
ary reconstruction.
Periodontal defects. Periodontal  defects  may  occur  as  a 
result of vascular compromise, inadvertent removal of the cer-
vical  interdental  bone,  or  major  damage  to  the  periodontal 
tissues. Defects also may occur by creating tears or vertical inci-
sions in the osteotomy area.
Nerve damage. Anesthesia  or  paresthesia  of  the  lower  lip, 
chin, and gums are the most common complications of man-
dibular body surgery. Generally, neurosensory deficit is tempo-
rary but can be permanent. Nerve damage usually is caused by 
edema  and  manipulation  of  the  neurovascular  bundle.  In  an 
anterior body ostectomy, where the anterior branch of the infe-
rior alveolar nerve  is sacrificed, the anterior teeth and gingiva 
may  be  numb  for  many  months  or  permanently.  If  a  major 
inferior alveolar or mental nerve injury is encountered during 
the surgery, immediate repair is indicated for the most predict-
able outcome.30-32
its  preservation.  The  basic  indications  for  mandibular  body 
osteotomies  are  (1)  occlusal  plane  leveling,  (2)  mandibular 
setback, (3) removal of edentulous space or teeth and associated 
bone, (4) narrowing or widening of the mandible, (5) lengthen-
ing of the mandible, and (6) distraction osteogenesis. Contra-
indications  include  adjacent  roots  that  are  too  close  together 
and  vascular  compromise  to  adjacent  soft  tissue  and  bone. 
Perform the osteotomies so that there will be maximum bony 
interface  following  the  repositioning  of  the  segments.  Signifi-
cant  bony  gaps  may  interfere  with  healing.  Precise  treatment 
planning  in  the  model  surgery  and  the  prediction  tracing  is 
paramount  for  success  in  body  osteotomies.  Rigid  fixation  is 
preferred for stabilization of the segments.
Effects on growth. Interdental osteotomies should not affect 
vertical alveolar growth, unless a tooth root is injured, resulting 
FIG 74-36 A, For mandibular prognathism, the sagittal split is 
completed in a similar fashion as for mandibular advancements. 
B, Bone from the proximal segment must be removed from the 
anterior and superior aspects. C, The segments can be inter-
digitated and rigid fixation used to stabilize the segments. 
A
B
C
FIG 74-37 For mandibular prognathic patients, using thesagit-
tal split ramus technique, where it moves posteriorly along the 
occlusal plane angle, the posterosuperior aspect of the distal 
segment is moved superiorly and posteriorly creating bony 
interference. This requires removal of bone above the medial 
cut, and along the posterior aspect of the proximal segment, 
posterior to where the vertical fracture occurs. 
Bone removed
Osteotomy
Medial Side
1074 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
align the segments appropriately for stabilization, preferably by 
rigid  fixation.  The  body  osteotomies  are  stabilized  with  rigid 
fixation first followed by the ramus rigid fixation.
Maxillary Procedures
Maxillary  deformities  can  occur  in  all  three  planes  of  space  
(AP,  vertical,  and  transverse).  Surgical  procedures  are  custom 
designed  for  each  patient.  The  maxilla  can  be  repositioned 
superiorly, inferiorly, anteriorly, posteriorly, or transversely and 
in one or more segments, depending on the nature of the defor-
mity.  Segmentalization  of  the  maxilla  permits  the  arch  to  be 
widened, narrowed, leveled, or the arch symmetry improved.
Basic maxillary Le Fort I surgical designs. There  are  four 
basic  maxillary  Le  Fort  I  surgical  designs  available.  The  oste-
otomies  can  be  completed  with  a  tapered  fissure  bur  or  a 
Simultaneous mandibular ramus and body procedures. Simul-
taneous ipsilateral mandibular body and ramus procedures can 
be  accomplished  providing  that  the  soft  tissues  are  managed 
appropriately. Maintaining the integrity of the inferior alveolar 
neurovascular  bundle,  particularly  in  posterior  segments,  is 
important. Careful management and protection of the lingual 
tissues is also vital. When mandibular sagittal split ramus oste-
otomies  are  performed  concomitant  with  mandibular  body 
procedures, it is generally recommended to complete the sagit-
tal  split  procedure  before  the  body  osteotomies.  If  the  body 
osteotomies  are  performed  first,  even  with  rigid  fixation,  the 
prying  forces necessary  to complete  the sagittal  split may dis-
place the body segments. If vertical oblique or inverted L oste-
otomies  are  performed  along  with  body  osteotomies,  either 
procedure  may be  completed first. Once  the  ramus and body 
osteotomies  are  completed,  the  occlusal  splint  can  be  used  to 
FIG 74-38 A and B, The vertical oblique osteotomy of the 
mandibular ramus can be used to set the mandible 
posteriorly. 
A
B
FIG 74-39 A and B, The inverted L osteotomy can be used to 
set the mandible posteriorly. A greater distance can be achieved 
than by the vertical oblique osteotomy. It also allows vertical 
lengthening or shortening of the ramus without affecting the 
major muscles of mastication. 
A
B
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1075
apex) from piriform rim to zygomatic buttress. In the buttress 
region, make a vertical step (usually 5 to 8 mm in length) and 
continue the horizontal osteotomy posteriorly at a  lower  level 
to  the pterygoid plates, usually parallel  to  the Frankfort hori-
zontal  plane.29  This  design  permits  straight  forward  or  back-
ward  movement  of  the  maxilla  and  eliminates  the  ramping 
effect. The maxillary step provides an additional area for graft-
ing with bone or synthetic bone if indicated. The maxillary step 
provides an AP reference point to help facilitate repositioning 
of the maxilla (Figure 74-42).
High Le Fort I osteotomy. Anterior maxillary osteotomies 
are made close to the infraorbital rim, carefully preserving the 
infraorbital nerve. Direct this osteotomy posteriorly at the but-
tress area at a lower level. Complete the osteotomy as described 
for the traditional Le Fort I osteotomy.
Maxillary horseshoe osteotomy. The  maxillary  horseshoe 
osteotomy  is  designed  to  keep  the  horizontal  palatal  shelf 
attached to the nasal septum and lateral nasal walls while mobi-
lizing the maxillary dentoalveolus (Figure 74-43).36 For superior 
movements, telescope the dentoalveolus over the stable palatal 
bone, maintaining the nasal airway dimensions. This technique 
may be used in select cases of vertical maxillary excess. Because 
the  vomer  and  septum  remain  attached  to  the  palate,  this  
technique may enable maxillary osteotomies  to be performed 
reciprocating  saw.  Preservation  of  the  descending  palatine 
vessels is important because approximately 80% of blood flow 
to  the  maxilla  normally  comes  from  these  vessels.33-36  Some 
surgeons, however, routinely place a vascular clip on the vessels 
or coagulate these vessels. Some studies have shown that pulpal 
blood  flow  is  not  altered  compared  with  preservation  of  the 
vessels. Circumvestibular incision is usually adequate, even with 
segmentalization.  However,  pedicle  flaps  may  be  necessary  in 
patients  with  compromised  vascularity  to  the  maxilla  (i.e., 
reoperated  maxilla,  cleft  deformity,  or  small  dento-osseous  
segments).  The  basic  maxillary  osteotomy  procedures  are 
detailed next.
Traditional Le Fort I osteotomy. The traditional Le Fort I 
osteotomy  is made with a  straight-line  cut  from  the piriform 
rim area (4 to 5 mm above apices of teeth) to the pterygoid plate 
area.  Surgical  separation  is  completed  at  the  pterygoid  plate/
tuberosity area, lateral nasal walls, and septum/vomer area. Be 
aware of the ramping effect of this osteotomy design, particu-
larly  with  maxillary  advancement  or  setback.  The  ramping 
effect occurs because of the horizontal osteotomy is not parallel 
to the Frankfort horizontal plane (Figure 74-41).
Maxillary step osteotomy. Make horizontal cuts parallel to 
the  Frankfort  horizontal  plane  (4  to  5 mm  above  the  canine 
FIG 74-40 A and B, Mandibular body osteotomies can be per-
formed in any area of the mandible to move the anterior 
segment of the mandible posteriorly or to alter the vertical and 
transverse position. Combining body osteotomies and sagittal 
splits of the ramus allows flexibility and movement of the pos-
terior and anterior segments independent of each other. Rigid 
fixation improves the stability and facilitates healing. 
A
B
FIG 74-41 A and B, A retruded maxilla undergoing a Le Fort I 
osteotomy for advancement. The traditional Le Fort I gener-
ally angles the osteotomy from a higher position anteriorly 
to a lower point posteriorly in the zygomatic buttress area. 
This creates a slope along the lateral maxillary wall. As the 
maxilla is advanced forward, it also moves superiorly along the 
bony ramp. 
A
B
45
41
1076 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
•  Correction of accentuated or reverse curves of occlusion
•  Elimination or creation of spacing within the arch
Segmentalization of the maxilla includes one or more inter-
dental osteotomies  coupled with midline or parasagittal oste-
otomies of the palate to permit repositioning of the maxilla in 
two or more segments. Orthodontic preparation should diverge 
the roots adjacent to the predetermined interdental osteotomy 
sites. Careful interdental vertical cuts should correlate with the 
model surgery and STO. One can make palatal cuts with a bur, 
saw, or osteotome, being careful to protect the integrity of the 
palatal  mucosa.  With  a  circumvestibular  incision,  the  blood 
flow  to  the  anterior  maxillary  segment  is  primarily  from  the 
palatal mucosa. Tears or injuries to the palatal mucoperiosteum 
may  lead  to  oronasal  fistula,  periodontal  defects,  or  avascular 
necrosis  of  the  anterior  segments.  Preserve  interdental  bone 
around the necks of teeth and over roots. Some surgeons prefer 
a  four-piece  maxilla  where  parasagittal  osteotomies  are  made 
on the palate where the palate becomes a separate, fourth maxil-
lary  segment.  For  three-piece or  four-piece maxillarysurgery, 
interdental  cuts  between  the  lateral  incisor  and  canine  fre-
quently  are  more  advantageous  than  cuts  between  the  canine 
and first premolar, because they allow for the following:
•  Control of incisor angulation
•  Ability to level the occlusion
•  Expansion or constriction of the posterior maxilla from the 
canines through the molars
•  Adjustment  for  tooth  size  discrepancies  in  the  anterior  
arch  by  creating  space  between  the  lateral  incisors  and 
canines  (Elimination  of  this  spacing  may  require  dental 
restorations.)
Stabilization
Rigid fixation. Rigid fixation for maxillary surgery implies 
the use of bone plates.  Ideally, one should use a minimum of 
four bone plates. Each side should have a plate in the piriform 
without an adverse effect on maxillary growth, unlike the other 
osteotomy designs.
Segmentalization of the maxilla. Segmentalization  of  the 
maxilla  has  several  advantages  over  one-piece  Le  Fort  I 
osteotomies:
•  Correction of transverse excesses or deficiencies
•  Correction of asymmetry (i.e., one cuspid is more anterior 
than the opposite cuspid and is corrected by advancing one 
side more than the other side)
•  Correction of transverse vertical deformities
FIG 74-42 A, The maxillary step osteotomy allows straightfor-
ward or posterior movement of the maxilla. The horizontal cuts 
are made parallel to the Frankfort horizontal plane. B, If the 
maxilla is advanced significantly, then it is necessary to graft 
with bone or synthetic bone along the horizontal osteotomy, at 
the maxillary step, and in larger advancements between the 
tuberosity and the pterygoid plates. 
B
A
FIG 74-43 A to D, The maxillary horseshoe technique maintains 
the attachment of the palatal bone to the septum and 
lateral nasal walls but mobilizes the remaining maxillary 
dentoalveolus. 
A B
C D
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1077
could  compromise  the  blood  flow  to  the  maxillary  segments. 
Design  a  lingual  splint  similarly  to  stabilize  a  segmented 
mandible.
Bone or synthetic bone grafting. Bone  or  synthetic  bone 
grafting frequently is required to fill bony defects, improve sur-
gical stability, and enhance healing, especially with large move-
ment (above 5 mm).
Autogenous bone. Local  autogenous  bone  for  grafting  is 
commonly available from the mandible. In double jaw surgery, 
following the sagittal split osteotomy, bone is usually available 
on the medial side of  the mandibular angle where  the medial 
fracture occurs. There is usually lingual cortex available that can 
be  cautiously  cut  with  a  thin  reciprocating  saw  blade,  being 
careful not to cut the angle off, just the lingual cortex. In addi-
tion, in concomitant total joint prostheses, the excised condylar 
head and neck can be used to graft the maxillary defects as well 
as harvested cornoid processes. Distant harvest sites including 
iliac crest, tibia, fibula, cranial bone, rib, and so on, can provide 
good quality bone for grafting. These grafts obviously require 
a  second  surgery  site.  The  healing  process  may  be  longer  for 
autogenous bone grafts than for porous block hydroxyapatite. 
Autogenous  grafts  are  preferred  by  the  authors,  but  they  are 
more difficult to contour than porous block hydroxyapatite.
Porous block hydroxyapatite. Porous block hydroxyapatite 
is a bone graft substitute used in orthognathic surgery (Figure 
74-45).38-42  With  this  material,  bone  and  soft  tissue  growth 
occurs through the pores and is complete by 3 to 4 months, with 
bone  maturation  occurring  after  that  (Figure  74-46).  Porous 
block hydroxyapatite  is easier  to work with and stabilize  than 
bone,  but  it  is  brittle  and  must  be  stress  shielded  (it  requires 
four  bone  plates  for  maxillary  stabilization)  during  its  initial 
healing phase. This material causes no adjacent bone resorption 
and rarely becomes infected, even when exposed to the maxil-
lary sinus. The material does not resorb. If exposed to the oral 
or  nasal  cavity,  porous  block  hydroxyapatite  most  likely  will 
become  infected  and  require  removal.  However,  with  careful 
management of the soft tissues, this risk is minimal.
Effects on growth. Le  Fort  I  osteotomies  for  the  normal 
growing  maxilla  or  the  deficient  growing  maxilla  effectively 
eliminates further AP growth, although vertical alveolar growth 
remains  essentially  unchanged.43-47  With  a  normal,  growing 
rim  area  and  one  plate  in  the  zygomatic  buttress  area.  For  
each  plate,  place  a  minimum  of  two  bone  screws  above  the 
osteotomy  and  two  screws  below  it.  The  bone  plates  must  be 
adapted so that they are positioned passively against the bone 
so  that  when  the  bone  screws  are  inserted  and  tightened,  the 
maxilla will not be displaced. Surgery must be more precise and 
exacting  with  use  of  rigid  fixation  than  with  other  fixation 
techniques.  Rigid  fixation  offers  more  stability  and  enhanced 
healing compared to interosseous wiring or suspension wiring 
techniques.37
Surgical stabilizing appliance (splint). Surgical  stabilizing 
appliances may assist  in repositioning and stabilizing the  jaws 
or  segments  thereof.  Use  an  intermediate  splint  to  reposition 
and rigidly stabilize one of the jaws so that it then can be used 
as a reference to reposition the other jaw (Figure 74-44). A final 
splint ensures proper repositioning of the jaws or segments in 
relation to each other. The final splint also may prevent trans-
verse maxillary relapse. Construct an occlusal splint on properly 
positioned dental models to fit between the occlusal surfaces of 
the upper and lower teeth. The splint may be secured to either 
jaw by wire fixation. Design a palatal splint (see Figures 74-18 
and 74-19) to help stabilize maxillary segments, and fit it along 
the palatal aspects of the crowns, but do not cover the occlusal 
surfaces. Relieve the palatal soft tissues in the splint construc-
tion so that no impingement occurs on the palatal tissues that 
FIG 74-44 A and B, An intermediate splint is made on dental 
models and is used to reposition one jaw into a predetermined 
position in relation to the stable jaw. Demonstrated here is the 
intermediate splint used to reposition the mandible, which will 
be rigidly stabilized and followed by maxillary repositioning. 
A
B
FIG 74-45 Porous block hydroxyapatite is a bone graft substi-
tute with pores ranging from 190 to 230 µm. It is composed of 
pure hydroxyapatite. 
1078 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
Therefore, an alar base cinch  suture usually  is  indicated  in 
maxillary  surgery  to  help  ensure  a  more  refined  and  esthetic 
result.  The  use  of  the  alar  base  cinch  suture  significantly 
improves  the  controllability  of  the  width  of  the  alar  bases.48 
Perform the alar base cinch suture following maxillary stabiliza-
tion and before closure of the incision. Place the suture intra-
orally  with  a  large  curved  needle.  Pass  the  needle  through 
adjacent  soft  tissue  of  the  alar  base  and  direct  it  upward  to  
catch  the  fibroadipose  tissue  at  the  alar  base.  Pass  the  needle 
from the lateral to the medial direction. Perform the procedure 
on the opposite alar base, again approaching from a lateral to 
medial  direction,  resulting  in  a  figure-eight  pattern.  Then 
tighten  the  suture  until  the  desired  width  of  the  alar  base  is 
achieved.  The  suture  material  of  choice  is  2-0  polydioxanone 
sutures. The alar base cinch suture controls the alar base width, 
improves nasal tip projection, decreases nasolabial angle promi-
nence,  decreases  lip  shortening,  and  helps  maintain  the  AP 
thickness of the upper lip, particularly at the superior portion 
of the upper lip.
V-Y closure. A V-Yclosure of the circumvestibular incision 
also  can  assist  in  the  esthetic  improvement  of  the  upper  lip 
(Figure  74-48).  Perform  a  predetermined  amount  of  vertical 
closure before closing  the horizontal aspect of  the  incision. A 
4-0 chromic suture usually is preferred for this closure. The alar 
base cinch suture and V-Y closure help to minimize lip shorten-
ing, maintain  lip  thickness,  improve  the amount of vermilion 
exposed, and support the upper lip tubercle.
Septoplasty. Once  the  maxilla  has  been  mobilized  and 
down-fractured, direct  access  to  the nasal  septum  is obtained 
easily. One can approach the entire septum, including the car-
tilaginous  portion,  vomer,  and  perpendicular  plate  of  the 
ethmoid bone. Carefully dissect the perichondrium and perios-
teum off the septum to expose the underlying septal bone and 
cartilage (Figure 74-49). Treat the septum by removing, cutting, 
or repositioning the involved bone and cartilage. Low-tension 
transseptal suturing may reapproximate the septal mucosa and 
help avoid the development of a septal hematoma. Indications 
for septoplasty include (1) correction of nasal airway obstruc-
tion  created  by  a  deviated  nasal  septum,  (2)  correction  of  a 
deviated septum that is causing an esthetic concern, (3) removal 
of bone spurs, or (4) prevention of post-surgical deviation of 
the  septum  when  the  maxilla  is  being  advanced  or  moved 
superiorly.
Inferior turbinoplasty or turbinectomy. Nasal  airway 
obstruction is common in patients with maxillary deformities, 
mandible, a Class III occlusion may develop. Although patients 
with vertical maxillary hyperplasia also have the AP component 
of growth affected, the vertical alveolar growth continues at the 
same excessive growth rate as pre-surgery,  thus usually main-
taining a stable occlusal relationship, but with a downward and 
backward jaw growth vector. Patients with cleft palates includ-
ing alveolar clefts may have deficient growth effects in all three 
planes of space.
The  maxillary  horseshoe  technique  (see  Figure  74-43),  or 
maxillary  dentoalveolar  osteotomy,  keeps  the  palatal  bone 
attached to the septum and lateral nasal walls. This technique 
demonstrates good maxillary growth post-surgically in patients 
with vertical maxillary hyperplasia.44 AP growth and horizontal 
and vertical growth may be maintained.
Age for surgery. Patients with normal or deficient growth of 
the  maxilla  should  be  deferred  for  surgery  until  maxillary 
growth is essentially complete, which is generally 15 years old 
for females and 17 to 18 years old for males. Operating before 
completion  of  growth  may  result  in  the  development  of  a  
Class  III  occlusal  tendency.  Patients  with  vertical  maxillary 
hyperplasia  can  be  operated  on  earlier,  around  13  years  for 
females and 14  to 15 years  for males, with  the understanding 
that  subsequent  growth  will  be  downward  and  backward 
because the vertical alveolar bone growth will continue at  the 
pre-surgical rate.43-47
Ancillary procedures in maxillary surgery. A number of addi-
tional  procedures  can  be  carried  out  to  enhance  the  quality  
of  results  with  maxillary  surgery.  These  procedures  can  have 
esthetic and functional effects.
Alar base cinch suture. The  intra-alar  base  width  almost 
always  increases when maxillary surgery  is performed (Figure 
74-47). The reasons for this are as follows:
•  The  soft  tissues,  particularly  the  periosteum  and  muscula-
ture, are detached from the lateral walls of the maxilla in the 
perinasal area.
•  Superior or anterior movements of the osseous structures in 
the  piriform  area  cause  widening  of  the  alar  base  because  
of  the  increased  prominence  of  the  supportive  skeletal 
structures.
•  The  tissue  edema  that  normally  occurs  with  maxillary 
surgery causes the alar base width to increase.
FIG 74-46 Histological assessment of a porous block hydroxy-
apatite graft 8 months after surgery demonstrates good bony 
ingrowth without evidence of inflammation. 
FIG 74-47 The alar base cinch suture is placed intraorally 
through the fibroadipose tissue of the alar base on one side (A), 
in a figure-eight fashion through the opposite side (B), and is 
secured. This controls the transverse width of the alar bases. 
A B
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1079
bone  or  soft  tissue  of  the  turbinates  is  larger  than  normal, 
causing  an  obstruction.  Relative  enlargement  means  that 
normal-sized  turbinates  cause  obstruction  because  of  the 
decreased  transverse  width  of  the  nasal  cavity.  This  is  more 
evident in patients with high occlusal plane facial morphology 
in which the transverse width of the functional nasal cavity is 
frequently  less  than  normal.49  In  addition,  patients  requiring 
maxillary  superior  repositioning  procedures  have  a  further 
decreased functional airway available as the nasal floor is moved 
upward and the inferior turbinates may create a physical obsta-
cle  preventing  the  maxilla  from  being  moved  upward,  thus 
increasing the need for turbinectomies in order to maintain a 
functional nasal airway and allow upward repositioning of the 
maxilla. Indications for removing a portion of the inferior tur-
binates  include nasal airway obstruction created by  the  turbi-
nates, hypertrophy of the bone or soft tissue components of the 
turbinates, and superior repositioning of the maxilla such that 
additional space is required to move the maxilla upward or to 
maintain a good functional nasal airway.
Approach  the  turbinates  following  down-fracture  of  the 
maxilla. Make an incision through the mucoperiosteum of the 
nasal floor, exposing the turbinate from its anterior aspect to its 
posterior extent (Figure 74-50). Perform a partial turbinectomy 
by direct excision of bone and mucosa (Figure 74-51). Hemo-
stasis  is achieved by electrocautery. Then close  the nasal floor 
mucoperiosteum  with  4-0  chromic  suture.  Perform  the  same 
procedure bilaterally.
Third molar removal. Removal  of  third  molars  may  be 
indicated in orthognathic cases for any of the following reasons:
•  Impacted tooth
•  Inadequate space within the arch for the tooth to erupt and 
be a functional tooth
•  Malalignment of the third molar creating lack of function
•  Associated pathological condition with the tooth
•  Recurrent pericoronitis
•  Location  within  the  osteotomy  site  that  may  render  struc-
tural weakness within the jaw component
The timing for removal of third molars in relation to orthog-
nathic  surgery  may  be  important.  Maxillary  third  molars, 
particularly  those with high occlusal plane  facial morphology 
with retruded maxilla and mandible. The nasal airway obstruc-
tion may be due to large inferior turbinates. Approximately 80% 
of  functional nasal airway occurs  from the top of  the  inferior 
turbinate to the nasal floor. Enlargement of the turbinates can 
be  absolute  or  relative.  Absolute  enlargement  means  that  the 
FIG 74-48 V-Y closure of the maxillary vestibular incision helps 
to maintain the thickness and length of the upper lip and the 
amount of vermilion exposed. 
FIG 74-49 The mucoperiosteum and perichondrium have been 
reflected from the nasal septum, revealing a large septal spur 
on the left side. This structure can be removed and any septal 
deviations corrected by incising, excising, and/or removing por-
tions of the septal bone and cartilage. 
FIG 74-50 An incision is made through the mucoperiosteum of 
the nasal floor to expose the turbinate from the anterior aspect 
to its posterior extent. This approach is performed unilaterally 
or bilaterally, depending on where the nasal airway obstruction 
is occurring in reference to the turbinates. 
1080 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome StabilityThis sequencing technique works particularly well when the 
occlusal plane angle is to be decreased and the mandible is to 
be  rotated  in  a  counterclockwise  direction.  An  intermediate 
splint  is  necessary  and  is  made  from  the  models  where  the 
mandible  has  been  repositioned  accurately  with  the  maxilla 
remaining in its original place. The AP and vertical position of 
the mandible being repositioned in the model surgery is deter-
mined  from  the  prediction  tracing  and  clinical  assessment. 
Complete the mandibular surgery using an intermediate splint 
for repositioning and then apply rigid fixation. Then reposition 
the maxillary model to occlude and function with the mandible. 
Apply  the  final  palatal  splint.  Place  the  maxilla  into  the  best 
functional  occlusal  relationship  with  the  mandible  and  apply 
intermaxillary fixation along with rigid fixation and bone graft-
ing if indicated. A palatal splint is the authors’ preferred method 
of  stabilizing  an  expanded  maxilla  because  the  splint  can  be 
kept in position for several months if necessary to maximize the 
transverse stability.
Repositioning the Maxilla First
When the maxilla is repositioned first, consider the forces that 
may  be  placed  on  the  repositioned  maxilla  by  whatever  indi-
cated  procedures  are  necessary  in  the  mandible.  The  recom-
mended treatment sequence is as follows:
1.  Perform mandibular ramus sagittal split osteotomies but do 
not complete the splits.
2.  Perform  maxillary  osteotomies,  segment  if  indicated,  and 
mobilize.
3.  Complete intranasal procedures if indicated (e.g., turbinec-
tomies and nasal septoplasty).
4.  Apply  maxillary  splint,  maxillomandibular  fixation,  rigid 
fixation, and grafting as necessary with bone or porous block 
hydroxyapatite.
5.  Complete mandibular sagittal split osteotomies, place into a 
maximal  occlusal  fit  (use  a  final  splint  if  surgeon  prefers), 
and  apply  maxillomandibular  fixation  and  rigid  fixation. 
Release maxillomandibular fixation and check occlusion.
6.  Perform other indicated procedures (i.e., genioplasties, facial 
augmentation, rhinoplasty).
In performing the sagittal split osteotomies on the mandible, 
a  bite  block  is  generally  necessary  in  order  to  perform  the 
medial osteotomy cuts, and much of the prying and forces may 
have  to  be  placed  on  the  mandible  to  separate  the  segments. 
During instrumentation, forces can be placed inadvertently on 
the maxilla, displacing it from its original position. Usually the 
best  procedure  is  to  perform  all  of  the  surgical  cuts  for  the 
mandibular ramus sagittal split osteotomy except for the final 
splitting of the mandible. This way, most of the force that may 
displace the maxilla is completed and the mandible can be used 
as a reference to reposition the maxilla.
If appropriate and accurate model surgery is performed, the 
maxilla can be repositioned anteroposteriorly, transversely, and 
vertically  using  the  mandible  as  the  base  reference.  Use  bone 
plates  in  double  jaw  surgery  because  of  increased  stability 
requirements. If a one-piece maxilla is planned, then construct 
a monoblock type of splint from the model surgery to position 
the  maxilla  at  surgery.  If  segmentalization  of  the  maxilla  is 
planned, make a final splint along with an intermediate splint 
to articulate with the lower teeth and undersurface of the final 
splint. Reposition  the mandible  into  its final position  to con-
struct the final splint. Then using a second mounted mandibu-
lar model, make an intermediate splint to interdigitate between 
whether they are impacted or erupted, can be taken out at the 
same  time  as  the  orthognathic  surgery  or  be  removed  a 
minimum of 9 months to 1 year before the surgery. If removed 
before surgery, it will take 9 to 12 months for the socket area to 
heal  adequately.  Orthognathic  surgery  within  6  months  of 
extraction  may  result  in  an  unfavorable  fracture  through  the 
tuberosity,  resulting  in  mobilization  of  the  anterior  aspect  of 
the  maxilla  but  with  the  posterior  tuberosity  area  remaining 
attached to the pterygoid plates and to the palatine bone. This 
may  cause  extreme  difficulty  in  mobilizing  and  repositioning 
the  maxilla.  When  removed  at  the  time  of  surgery,  the  third 
molars  are  extracted  most  easily  following  the  down-fracture 
and  mobilization  of  the  maxilla.  This  helps  prevent  aberrant 
fracturing through the tuberosity area.
Special Considerations
To obtain the optimal functional and esthetic results,  it  is fre-
quently necessary to perform double jaw surgery. Appropriate 
treatment planning and sequencing of the various procedures 
are  necessary  to  achieve  optimal  outcomes.  The  options  in 
sequencing of double jaw surgery are repositioning the maxilla 
first or the mandible first.
Repositioning the Mandible First
Repositioning the mandible first in most cases provides overall 
improved  predictability  of  the  final  esthetic  outcome.18  The 
sequencing when the mandible is repositioned first is as follows:
1.  Completion of mandibular sagittal split osteotomies, repo-
sitioning with intermediate splint, application of intermaxil-
lary fixation, and application of rigid fixation
2.  Completion of maxillary osteotomies and mobilization
3.  Intranasal  procedures,  such  as  turbinectomies  and  nasal 
septoplasty
4.  Application of  the final splint, maxillomandibular fixation, 
rigid fixation to the maxilla, and appropriate bone grafting, 
if  indicated,  with  bone  or  porous  block  hydroxyapatite; 
release maxillomandibular fixation and check occlusion
5.  Other procedures (i.e., genioplasty,  facial augmentation, or 
rhinoplasty)
FIG 74-51 Partial turbinectomies are performed, removing the 
inferior portion. 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1081
•  Often an accentuated curve of Spee in the mandibular arch 
and sometimes a reversed curve in the maxillary arch
•  Anterior deep bite
•  Decreased angulation of the maxillary incisors as in the Class 
II, division 2 malocclusion, but overangulated incisors also 
are possible
•  Decreased angulation of the mandibular incisors
Surgical increase of the occlusal plane. Patients demonstrat-
ing the low occlusal plane facial type may benefit functionally 
and  esthetically  by  increasing  the  occlusal  plane  angle  with  a 
clockwise  rotation  of  the  maxillomandibular  complex  to  fall 
within the normal range (8 ±4 degrees). To illustrate the specific 
changes associated with a clockwise rotation of the jaws, a case 
with a Class I occlusion is used, and the maxillary central incisor 
edge  functions  as  the  center  of  rotation  (Figure  74-52).  The 
following changes occur:
•  Occlusal plane angle increases.
•  Mandibular plane angle increases.
•  Chin rotates posteriorly.
•  Posterior facial height decreases.
•  Perinasal bone structures advance.
•  Maxillary incisor angulation decreases.
•  Mandibular incisor angulation increases.
Clockwise rotations have become one of the most acceptable 
methods for treating patients and should provide adequate sta-
bility because all of the muscles of mastication remain basically 
the  same  length  or  shortened.  The  center  of  rotation  of  the 
maxillomandibular complex effects  the esthetic change.  If  the 
point of rotation  is at  the  incisor  tips,  then the perinasal area 
advances and the chin rotates posteriorly. If the point of rota-
tion  is  at  point  A,  then  the  perinasal  area  is  not  affected  as 
significantly, but the upper incisor edge and the inferior aspect 
of  the  upper  lip  rotate  posteriorly  and  the  chin  rotates  even 
further  posteriorly.  Pure  vertical  or  AP  movements  (without 
rotation) do not affect the occlusal plane angulation or incisor 
the lower teeth and thelower occlusal imprint of the final splint. 
Following  repositioning  of  the  maxilla,  complete  the  sagittal 
splits  and  set  the  mandible  into  its  final  position  and  apply 
appropriate stabilization. Mandibular segmental or body oste-
otomies, if indicated, generally are performed after the sagittal 
splits are complete. Then the chin and other procedures can be 
performed.
Occlusal Plane Alteration
The correction of dentofacial deformities often requires double 
jaw surgery to achieve a quality functional and esthetic result. 
An  often  ignored  but  important  cephalometric  and  clinical 
interrelationship  in  the  diagnosis  and  treatment  planning  for 
the  correction of dentofacial  deformities  is  the occlusal  plane 
angulation.50-54 The occlusal plane angle is formed by the Frank-
fort horizontal plane and a line tangent to the cusp tips of the 
lower premolars and the buccal groove of the second molar. The 
normal  value  for  adults  is  8 ±4  degrees.  An  increased  (high) 
occlusal  plane  angle  usually  is  reflected  in  an  increased  man-
dibular  plane  angle  (dolichocephaly),  and  a  decreased  (low) 
occlusal  plane  angle  usually  correlates  with  a  decreased  man-
dibular plane angle (brachycephaly).
Traditional management in double jaw surgery, regardless of 
the  steepness  of  the  pre-surgical  occlusal  plane,  manages  the 
occlusal plane angle in one of the following manners: (1) main-
tains the pre-surgical occlusal plane angulation, (2) establishes 
the  occlusal  plane  angle  by  autorotation  of  the  mandible 
(usually in an upward and forward direction), or (3) selectively 
increases  the  occlusal  plane  relative  to  Frankfort  horizontal 
plane  to  “improve  stability.”  Although  these  methods  may 
achieve an acceptable relationship of  the teeth  in centric rela-
tion, they commonly do not provide the optimal functional and 
esthetic relationship of the musculoskeletal structures and the 
dentition.  As  the  occlusal  plane  angle  increases  in  steepness 
(high occlusal plane angle) and begins to approach the slope of 
the  TMJ  articular  eminence,  certain  functional  problems  can 
develop, including the following:
•  Loss of canine rise occlusion
•  Loss of incisal guidance
•  Development of working and nonworking posterior dental 
functional interferences
If  the clinician believes  in the protected occlusion philoso-
phy, there may be concern over the application of the traditional 
treatment modalities of increasing the angulation of the occlu-
sal plane in certain types of cases.
Morphological facial types. Two  facial  types  that  may 
benefit for occlusal plane alteration are the low occlusal plane 
brachycephalic  type  and  the  high  occlusal  plane  dolichoce-
phalic type.
Low occlusal plane facial type. The patient with a low occlu-
sal plane facial  type may require an increase  in occlusal plane 
angulation. Some of the basic clinical and radiographic charac-
teristics  of  the  low  occlusal  plane  facial  type  include  the 
following:
•  Decreased occlusal plane angulation (occlusal plane less than 
4 degrees)
•  Low mandibular plane angulation
•  Prominent mandibular gonial angles
•  Strong  chin  in  relation  to  the  mandibular  alveolus  (AP 
macrogenia)
•  Most often Class II malocclusion, although Class I or Class 
III also occur
FIG 74-52 Surgical increase of the occlusal plane rotates the 
chin posteriorly in relation to the incisor tips, the perinasal areas 
advance, the posterior facial height decreases, the maxillary 
incisor angulation decreases, and the mandibular incisor angula-
tion increases. 
0°
8°
1082 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
•  Mandibular incisor angulation decreases (the same amount 
that the mandibular occlusal plane decreases).
•  Projection of the chin increases relative to the lower incisor 
edges.
•  Posterior facial height may increase.
•  Prominence of the mandibular angles may increase.
•  Perinasal area moves posteriorly in relation to the maxillary 
incisor edges.
•  Incisal  guidance  and  canine  rise  occlusion  improves,  and 
posterior  working  and  nonworking  interferences  are 
eliminated.
•  Oropharyngeal airway increases.
The center of rotation affects the esthetic relationship of the 
jaws with the other facial structures. If the center of rotation is 
at the maxillary incisor edge, as in Figure 74-54, the perinasal 
area, subnasale area, and the nasal tip move posteriorly and the 
chin  comes  forward.  If  rotation  is  around  point  A  or  higher, 
then  the perinasal  area and  the nose are  less affected, but  the 
maxillary incisor edges come forward, increasing the AP support 
to  the  upper  lip.  The  chin  also  comes  further  forward. When 
decreasing the occlusal plane angle and advancing the mandi-
ble, the oropharyngeal airway increases approximately 50% of 
the advancement measured at the genial tubercles. Figure 74-54 
demonstrates the significant esthetic difference that the altera-
tion of the occlusal plane can make.50-54 Evaluation of the status 
of the TMJ before surgery is important, particularly when one 
is  decreasing  the  occlusal  plane  angulation.  The  movement 
associated with decrease of the occlusal plane increases pressure 
in the joints until the muscles, soft tissues, and dento-osseous 
structures have a chance to equilibrate. If the joints are healthy 
and  stable,  they  should  be  able  to  withstand  the  increased 
loading  through  the  adaptation  phase.  Conversely,  carefully 
assess and appropriately manage patients with pre-existing TMJ 
disorder  so  that  the  joints  will  be  stable  when  the  surgery  is 
performed.
angulation.  These  movements,  however,  have  an  influence  on 
lip function and esthetics.
The  surgical  approach  to  increase  the  occlusal  plane  com-
pared with decreasing the occlusal plane may vary in sequenc-
ing  of  maxillary  and  mandibular  osteotomies  during  surgery. 
Accurate  pre-surgical  prediction  tracings  and  accurate  model 
surgery simplify the surgery and enhance the accuracy and sta-
bility  of  the  treatment  outcome.  With  the  low  occlusal  plane 
facial  type, most surgeons may find  it easier  to reposition the 
maxilla first with rigid fixation, creating a posterior open bite 
that  can  be  set  up  with  an  intermediate  splint  (made  from 
accurate  model  surgery).  The  mandible  then  is  moved  into 
proper alignment with the maxilla by using ramus osteotomies 
(preferably  sagittal  split  osteotomies).  Usually,  bone  must  be 
removed  from  the  medial  aspect  of  the  proximal  segment, 
directly above the level of the medial horizontal cut. This bone 
is consistently an area of interference if it is not removed. The 
use of rigid fixation eliminates the need for intermaxillary fixa-
tion after surgery and is most helpful in achieving a predictable 
outcome  when  properly  applied.  One  must  take  care  not  to 
overload the TMJs.
High occlusal plane facial type. The  characteristics  of  the 
high occlusal plane facial type generally include the following:
•  Increased occlusal plane angulation  (occlusal plane greater 
than 12 degrees)
•  Increased mandibular plane angulation
•  Anterior vertical maxillary hyperplasia and/or posterior ver-
tical maxillary hypoplasia
•  Increased  vertical  height  of  the  anterior  mandible  and/or 
decreased vertical height of the posterior mandible
•  Decreased projection of the chin (AP microgenia)
•  AP  and  vertical  posterior  mandibular  and  maxillary 
hypoplasia
•  Decreased angulation of maxillary incisors, although overan-
gulation can occur
•  Increased angulation of mandibular incisors
•  Class II malocclusion is common, although Class I and Class 
III malocclusions also can occur
•  An anterior open bite may be accompanied by an accentu-
ated curve of Spee in the upper arch
•  In  more  pronouncedcases  in  which  the  occlusal  plane 
approaches the slope of the articular eminence, the following 
may occur: loss of incisal guidance, loss of canine rise occlu-
sion,  and  the  presence  of  working  and  nonworking  dental 
interferences in the molar areas
•  The more severe cases may demonstrate moderate to severe 
sleep  apnea  symptoms  as  a  result  of  the  tongue  base  dis-
placed posteriorly and constricting the oropharyngeal airway 
(normal oropharyngeal airway space is 11 ±2 mm)
Surgical decrease of the occlusal plane. In the high occlusal 
plane facial type, the indicated surgical correction may include 
a counterclockwise rotation of the maxillomandibular complex. 
In  open  bite  cases  or  deep  bite  cases,  the  maxillary  occlusal 
plane and the mandibular occlusal plane may be different and 
each  should  be  evaluated  independently.  For  illustrative  pur-
poses, a Class I case is used with the maxillary incisor edge as 
the center of rotation (Figure 74-53). The anatomical changes 
that occur include the following:
•  Occlusal plane angle decreases.
•  Mandibular plane angle decreases.
•  Maxillary  incisor  angulation  increases  (the  same  amount 
that the maxillary occlusal plane decreases).
FIG 74-53 Surgical decrease of the occlusal plane rotates the 
chin forward, decreases prominence of the perinasal areas, 
maxillary incisor angulation increases, mandibular incisor angu-
lation decreases, and the oropharyngeal airway increases. 
16°
8°
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1083
reduction glossectomy (surgical  reduction of  the  tongue  size) 
to  improve  function,  esthetics,  and  treatment  stability.  A 
number of congenital and acquired causes of true macroglossia 
exist, including the following:
•  Muscular hypertrophy
•  Glandular hyperplasia
•  Hemangioma
•  Lymphangioma
Macroglossia  occurs  commonly  in  conditions  such  as  
Down  syndrome  and  Beckwith-Wiedemann  syndrome. 
Acquired factors may include acromegalia, myxedema, amyloi-
dosis, tertiary syphilis, cysts or tumors, and neurological injury.55 
Specific clinical and cephalometric features may help the clini-
cian  identify  the presence or absence of macroglossia. Not all 
these  features  are  always  present,  and  their  existence  is  not 
necessarily  pathognomonic  for  the  diagnosis  of  macroglossia. 
The clinical features and the radiographic features are listed at 
the end of the section. Most open bites are not related to mac-
roglossia. In fact, it has been established that closing open bites 
with orthognathic surgery allows a normal tongue, which is an 
adaptable organ,  to  readjust  to  the altered volume of  the oral 
cavity, with little tendency toward relapse.56,57
If  true  macroglossia  is  present  with  the  open  bite,  then 
instability  of  the  orthodontics  and  orthognathic  surgery  are 
likely  to  occur,  with  a  tendency  for  the  open  bite  to  return. 
Pseudo  macroglossia  is  a  condition  in  which  the  tongue  may 
be  normal  in  size,  but  it  appears  large  in  relation  to  its  ana-
tomical  interrelationships,  such  as  maxillary  and  mandibular 
hypoplasia.
Patients with true macroglossia may be candidates for reduc-
tion  glossectomy.  The  most  common  technique  used  is  the 
keyhole or midline elliptical excision and anterior wedge resec-
tion.  The  tongue  flaps  then  are  sutured  back  together  in  a 
straight line (Figure 74-55). In the presence of musculoskeletal 
When the occlusal plane angle is decreased, it is usually easier 
first to set the mandible into its new position, creating a poste-
rior open bite. An intermediate splint helps align the mandible 
in  its  new  position,  and  then  rigid  fixation  is  applied  to  the 
mandible.  Usually  a  four-  or  six-hole  Z-plate  with  2-mm–
diameter  monocortical  screws  provides  adequate  stability  for 
mandibular  setbacks  and  for  most  mandibular  advancements 
(see  Figure  74-35).  However,  for  large  advancements,  one  or 
two  bone  screws  can  be  placed  in  the  ascending  ramus  for 
additional  stability.  This  makes  the  maxillary  surgery  much 
easier to perform with better positional accuracy. Stabilization 
of  the  maxilla  is  achieved  with  four  bone  plates  and  bone  or 
porous block hydroxyapatite grafting to fill any osseous defects. 
In some cases, the vertical height of the ramus may be increased. 
However, because most of the cases requiring this type of move-
ment are skeletal and occlusal Class II malocclusions, the distal 
segment  moves  inferiorly  but  anteriorly  to  the  pterygoid-
masseteric  sling.  In  Class  III  skeletal  and  occlusal  relations 
because  the  ramus  portion  of  the  distal  segment  must  move 
down through the sling (which can occur in Class III facial types 
with  high  occlusal  and  mandibular  angles),  the  pterygoid-
masseteric sling can be split to allow the posteroinferior aspect 
of the distal segment to rotate down through the sling. The bone 
eventually  remodels  back  up  to  the  height  of  the  sling.  Rigid 
fixation  eliminates  the  requirement  for  post-surgery  maxillo-
mandibular  fixation,  and  usually  light  guiding  elastics  are  all 
that are necessary to control the occlusion after surgery.
Tongue Assessment
An  enlarged  tongue  can  cause  dentoskeletal  deformities  and 
instability of orthodontics and orthognathic surgical treatment 
and  can  create  masticatory,  speech,  and  airway  management 
problems.  Understanding  the  signs  and  symptoms  of  macro-
glossia  helps  identify  those  patients  who  can  benefit  from 
FIG 74-54 With the fulcrum of rotation located at the incision 
tips, the changes created by increasing the occlusal plane or 
decreasing the occlusal plane can be appreciated. Of course, 
anteroposterior (AP), vertical, and transverse movements are 
also usually involved to obtain the ideal functional and esthetic 
outcomes. 
16°
8°
0°
FIG 74-55 The keyhole procedure is the most common tech-
nique used for reduction glossectomy. A, Midline elliptical 
and anterior wedge resection outlined. B, Tissue removed. 
C, Midline closure. 
A B
C
1084 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
position,  occlusion,  and  orthognathic  surgical  outcomes 
include:  (1)  articular  disc  dislocation,  (2)  AICR,  (3)  reactive 
arthritis, (4) condylar hyperplasia, (5) ankylosis, (6) congenital 
deformation  or  absence  of  the  TMJ,  (7)  connective  tissue  
and autoimmune diseases, and (8) other end-stage TMJ pathol-
ogies. These TMJ conditions are often associated with dentofa-
cial deformities, malocclusion, TMJ pain, headaches, myofascial 
pain, TMJ and jaw functional impairment, ear symptoms, sleep 
apnea, and so on.16,58 Patients with these conditions may benefit 
from  corrective  surgical  intervention  including  TMJ  and 
orthognathic surgery. Many clinicians may have difficulty iden-
tifying the presence of a TMJ condition, diagnosing the specific 
TMJ  pathology,  and  selecting  the  proper  treatment  for  that 
condition. This section should improve the clinician’s diagnos-
tic and treatment planning skills.
Although  most  TMJ  patients  have  associated  symptoms, 
approximately 25% of patients with TMJ pathology/disorders 
will be asymptomatic. Accurate diagnosis and proper  surgical 
intervention  for  the  specific  TMJ  pathologies  that  may  be 
present  in  orthognathic  surgery  patients  will  provide  highly 
predictable and stable results.15,16,58
When  coexisting  conditions  do  exist,  separate  or  simul-
taneous  management  of  the  TMJ  pathology  and  dentofacial 
deformity may be indicated. In most cases, correct TMJ prob-
lems first.
Surgical  TMJ  treatment  modalities  are  determined  from 
patient  history,  clinical  assessment,  imaging  (tomography, 
MRI), cause, time since onset, TMJ anatomy, durationof symp-
toms, type of previous treatment, number of previous surgeries, 
and  presence  of  systemic  or  other  local  conditions.  A  brief 
description of the types of TMJ problems and treatment recom-
mendations follow.
Articular disk displacement. In patients with TMJ articular 
disk displacement with or without reduction, carefully evaluate 
the health of the disk and surrounding joint structures. With a 
salvageable disk and healthy condylar and fossa elements, target 
treatment at stabilizing the disk by repositioning and ligament 
repair. Articular disk repositioning and ligament repair with a 
Mitek  suture  anchor  and  artificial  ligaments  will  provide 
improved  stability  over  other  traditional  techniques  (Figure 
74-56).59-66 The success rate is high if this surgery is performed 
within the first 4 years of the onset of symptoms and there  is 
no presence of reactive arthritis, polyarthritic, or other systemic 
and localized diseases. After 4 years, the success rate decreases 
as the disc becomes more degenerated and deformed.
Adolescent internal condylar resorption. AICR  is  a  poorly 
understood but well documented condition that can affect the 
TMJs. This condition is predominately in teenage females (8 : 1 
female-male  ratio)  and  is  initiated  as  they  progress  through 
their pubertal growth spurt (onset between 11 to 15 years old), 
with anterior displaced articular discs and progressive condylar 
resorption  (Figure  74-57).  It  can  proceed  until  remission,  or 
result  in  complete  loss  of  the  condylar  head.  AICR  may  be 
hormonally mediated and is seen predominantly in high occlu-
sal plane/high mandibular plane angle facial types. In this pro-
gressive disease process, the articular disks are always anteriorly 
dislocated. If the disk is salvageable, repositioning it, removing 
the hypertrophied synovial and bilaminar tissues, and stabiliz-
ing the disk with a Mitek anchor has been proved by Wolford 
and colleagues to be a stable and predictable approach to treat 
this condition.59,64,66-68 Orthognathic surgery can be done in the 
same operation or performed in a second operation. If the TMJs 
deformity with a malocclusion and true macroglossia, there are 
basically three choices on surgical sequencing:
•  Stage  1:  Reduction  glossectomy;  stage  2:  Orthognathic 
surgery
•  Stage  1:  Orthognathic  surgery;  stage  2:  Reduction 
glossectomy
•  Perform  the  orthognathic  surgery  and  reduction  glossec-
tomy in one surgical stage
The option of performing the reduction glossectomy first as 
an isolated procedure and the orthognathic surgery second has 
the following advantages compared with the combined proce-
dure:  (1)  less  airway  concern,  (2)  no  intermaxillary  fixation 
required,  and  (3)  pre-surgical  orthodontics  when  performed 
after the reduction glossectomy that are more stable and predict-
able. Performing the reduction glossectomy as the primary stage 
is  indicated when extensive orthodontics are necessary before 
the  orthognathic  surgery  and  the  size  of  the  tongue  impedes  
the required orthodontic movements. Reducing the size of the 
tongue in these cases is indicated to facilitate the stability of the 
pre-surgical orthodontics. The second sequencing option would 
be indicated if occlusal instability developed after orthodontics 
and orthognathic surgery as a result of an enlarged tongue. The 
development of dentoskeletal changes directly related to tongue 
size,  such as an anterior open bite or a Class  III occlusal  ten-
dency, would indicate that reduction glossectomy may be ben-
eficial. In performing the treatment simultaneously with rigid 
fixation,  it  is  usually  helpful  to  complete  the  orthognathic 
surgery first. Once the orthognathic surgery is rigidly stabilized, 
one can perform a reduction glossectomy. Because a reduction 
glossectomy generally causes a transient but significant increase 
in  the  size  of  the  tongue  because  of  edema,  performing  the 
tongue procedure last may allow the occlusion to be established 
better  before  the  onset  of  edema.  However,  if  the  tongue  is 
extremely  large,  the  reduction  glossectomy  may  need  to  be 
sequenced first to allow the proper occlusion to be established 
when the orthognathic surgery is performed. With the surgical 
procedures, one must use care not to injure the lingual, hypo-
glossal, and glossopharyngeal nerves. Although the indications 
for  reduction  glossectomy  are  few,  when  the  procedures  are 
indicated, the following conclusions can be drawn:
•  Reduction glossectomy can improve functional and esthetic 
outcomes significantly.
•  The anterior  resection combined with  the midline keyhole 
type procedure is the best technique.
•  Improved  function relative  to airway,  speech, and mastica-
tion can be anticipated.
•  If the excessively large tongue is causing significantly unfa-
vorable  mandibular  growth,  reduction  of  the  tongue  may 
help control the problem.55
Temporomandibular Joint Management
The TMJs are the foundation for jaw position, facial growth and 
development, function, occlusion, facial balance, and comfort. 
If  the  TMJs  are  not  stable  and  healthy  (non-pathological), 
patients  requiring  orthognathic  surgery  may  have  unsatisfac-
tory  outcomes  relative  to  function,  esthetics,  occlusal  and  
skeletal stability, and pain.
TMJ disorders/pathology and dentofacial deformities com-
monly coexist. The TMJ pathology may be the causative factor 
of the jaw deformity, develop as a result of the jaw deformity, 
or  the  two  entities  develop  independent  of  each  other.  The  
most  common  TMJ  pathologies  that  can  adversely  affect  jaw 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1085
FIG 74-56 A, The Mitek mini anchor measures 1.5 mm x 5 mm and has an eyelet to support 
two 0-Ethibond sutures. B, The excess bilaminar tissue surrounding the condyle is excised and 
the disc mobilized to sit passively over the condyle. C, Posterior view shows placing the anchor 
8 mm below the top of the condylar head and lateral to the mid-sagittal plane. Three throws 
from each of the two sutures are placed through the posterior band of the disc. D, The disc is 
held in position with the Mitek anchor and supportive artificial ligaments. 
A B
C D
Mitek
L
0-Ethibond
suture
M
FIG 74-57 A, Adolescent internal condylar resorption (AICR) is a condition resulting in anterior 
disc dislocation (red arrow) and progressive condylar resorption. B, The discs (red arrow) com-
monly become nonreducing on opening early in the pathological progression. 
A B
1086 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
These conditions are  treated best by condylectomy, diskec-
tomy,  joint  débridement,  and  reconstruction  with  an  FDA-
approved  total  joint  prosthesis  (preferably  patient-fitted),  as 
well as fat grafts to the TMJ area generally harvested from the 
abdomen  or  buttock. Wolford  and  Karras  have  demonstrated 
that fat grafts packed around the prosthesis significantly reduce 
fibrosis and heterotopic bone formation around joints, improv-
ing treatment outcomes and significantly decreasing the risk of 
further surgery being required for removal of these unfavorable 
tissues.75-78 With the use of patient-fitted total joint prostheses, 
the  significant  mandibular  deformities  can  be  corrected  by 
repositioning the mandible on a reproduced three-dimensional 
model of  the patient’s TMJ and  jaw anatomy. A patient-fitted 
joint  prosthesis  is  designed  and  constructed  to  fit  the  TMJ 
anatomy  and  the  new  position  of  the  mandible  (see  Figure 
74-32).  With  total  joint  prostheses,  the  TMJ  is  reconstructed 
and  the  mandible  repositioned  into  its  most  ideal  position.  
Maxillary  surgery  and  other  procedures  can  be  performed 
concomitantly.
Condylar hyperplasia type1. Condylar  hyperplasia  type  1 
causes increased size of the condyle(s) and mandible with onset 
usually occurring during puberty with an accelerated and pro-
longed  growth  aberration  of  the  “normal”  condylar  growth 
mechanism  causing  condylar  and  mandibular  elongation 
(prognathism)  (Figure  74-59,  D-F).  Growth  is  self-limiting 
usually ending by the early to middle 20s, and can occur bilater-
ally  (condylar  hyperplasia  type  1A)  or  unilaterally  (condylar 
hyperplasia type 1B). Patients may begin with a Class I occlusal 
and  skeletal  relationship  as  they  enter  their  pubertal  growth 
phase and grow into a Class III skeletal and occlusal relationship 
or  begin  as  a  Class  III  and  develop  into  a  worse  Class  III  
are  not  addressed,  orthognathic  surgery  procedures  will  pre-
dictably cause further resorption of the condyles, resulting in a 
Class  II  anterior open bite  skeletal  and dental  relationship,  as 
well as increased pain.
Articular disk dislocated, nonsalvageable; condyle and fossa 
in good condition. When  the  articular  disk  is  dislocated  and 
nonsalvageable without perforation but the condyle and fossa 
are in good condition, there are three basic surgical approaches 
for TMJ management:
1.  Arthroscopy  can  be  a  consideration,  particularly  if  no 
orthognathic surgery is required. Arthroscopy is not recom-
mended  for  the  Class  II  patient  requiring  mandibular 
advancement  or  any  procedure  in  which  increased  TMJ 
loading occurs as a result of the orthognathic surgery.
2.  If the disk requires replacement, consider one of the follow-
ing  techniques,  in  order  of  preference:  (1)  sternoclavicular 
disk graft, (2) temporal fascia graft, (3) dermal graft, and (4) 
auricular  cartilage  graft.  The  sternoclavicular  joint  is  the 
most similar joint in the body to the TMJ functionally, struc-
turally, and histologically. The articular disk is similar to the 
TMJ  articular  disk.  A  split-thickness  or  full-thickness  disk 
graft can be harvested and stabilized to  the condyle with a 
Mitek anchor and also to the medial capsule,  lateral ptery-
goid muscle, bilaminar tissue, and lateral capsule. Although 
a relatively new technique, initial results are favorable. Tem-
poral fascial, dermal, and auricular cartilage grafts, thin with 
loading, may perforate, and may result in further degenera-
tive changes of the disk replacement tissue, fossa, and condyle 
(including  condylar  resorption)  in  a  large  percentage  of 
patients with a significant risk of requiring further surgery.69,70
3.  Total  joint  prostheses  are  the  most  predictable  method  of 
treatment  for  this  specific  situation because  they eliminate 
the risks of using autogenous tissues.71-74
Articular disk and condyle nonsalvageable (end-stage). When 
the articular disk and condyle are not salvageable, the following 
treatment  options  are  available:  (1)  sternoclavicular  graft 
including the articular disk, (2) costochondral graft, or (3) total 
joint prostheses. The preferred autogenous tissue is the sterno-
clavicular  graft  because  of  its  strength,  available  length,  good 
medullary bone, articular disk, and similarity to the TMJ. The 
costochondral graft lacks strength and can warp under loading, 
resulting in difficulty in controlling the occlusion after surgery, 
and there is no disk. However, if there is the presence of reactive 
arthritis,  polyarthritis  conditions,  systemic  or  local  diseases,  
two  or  more  previous  TMJ  surgeries,  or  significantly  altered 
joint anatomy, then using autogenous tissues may have a high 
failure rate.
The total joint prosthesis is the method of choice, is highly 
predictable, and is the best treatment option for end-stage TMJ 
pathology.71-74 A number of degenerative joint conditions pre-
clude the use of autogenous tissues for a predictable outcome. 
These conditions include the following:
•  Degenerative changes resulting in a nonsalvageable disk and 
condyle, with degenerative changes also in the fossa
•  Reactive arthritis
•  Failed TMJ autogenous grafts or alloplastic devices
•  Two or more previous surgical procedures to the TMJ
•  The  presence  of  connective  tissue/autoimmune  disease 
affecting the joint, such as juvenile idiopathic arthritis (JIA; 
Figure  74-58),  psoriatic  arthritis,  psoriasis,  lupus,  sclero-
derma, Sjögren syndrome, ankylosis  spondylitis, and rheu-
matoid arthritis
FIG 74-58 Connective tissue/autoimmune diseases affecting 
the temporomandibular joints (TMJs) can commonly cause 
major condylar resorption, although the disc may remain in 
reasonably good position, but may be surrounded by a reactive 
pannus as seen in this case of juvenile idiopathic arthritis (JIA). 
The structures are outlined in orange. 
FIG 74-59 Cone beam computed tomography (CT) of temporomandibular joints (TMJs). A to 
C, Normal TMJ with balanced joint spaces. D to F, Condylar hyperplasia type 1 with relatively 
normal condylar shape, elongated condylar head and neck, and narrow joint space related to thin 
articular disc or displaced disc. In the coronal view the condylar head is more rounded. G to 
I, Condylar hyperplasia type 2A is an osteochondroma with a vertical growth vector without 
significant horizontal condylar enlargement or exophytic growth. This is a “young” osteochon-
droma with only about 3 years of growth. J to L, Condylar hyperplasia type 2A, with a larger and 
wider condylar head and neck that may be in a transitional phase progressing toward condylar 
hyperplasia type 2B. M to O, Condylar hyperplasia type 2B with horizontal (as well as vertical) 
enlargement of the condyle and exophytic outgrowth of the tumor. This tumor has been present 
for 6 years. Notice the significant increased vertical height of the mandibular body, ramus and 
condylar head and neck. 
A B C
D E F
G H I
J K L
M N O
1088 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
tube to the oral endotracheal tube. Following completion of the 
orthognathic portion and release of intermaxillary fixation, one 
option is to remove the nasal endotracheal tube and insert an 
oral endotracheal tube. The second technique involves stabiliz-
ing the tube intraorally with a clamp and then pulling the nasal 
portion  of  the  tube  out  through  the  mouth,  thus  eliminating 
the need to change out the tube and eliminating the use of the 
laryngoscope. Each of these techniques provides complete and 
unobstructed access  to  the nasal  structures since  the endotra-
cheal tube has been transitioned to an oral tube. The anesthetist 
must  take  extreme  care  during  oral  intubation  not  to  place 
excessive pressure on  the maxilla or mandible  that  could dis-
place the dento-osseous segments. The alternative to simultane-
ous  surgery  is  to  perform  the  orthognathic  surgery  first  and 
then to perform the rhinoplasty. The rhinoplasty should not be 
carried out as the first surgical stage. Performing rhinoplasty at 
the same time as orthognathic surgery is challenging. Because 
of  the  edema  present  from  just  performing  the  orthognathic 
aspect  and  because  of  any  spatial  changes  of  the  underlying 
dento-osseous  structures,  significant  alteration  and  distortion 
of the soft tissues in and around the nose, cheeks, and upper lip 
occurs. Careful planning before the surgery to incorporate the 
expected  final  soft  tissue  changes  from  just  the  orthognathic 
surgery and then plan and execute the rhinoplasty procedures 
at the same time as the orthognathic surgery. The nasal dorsum 
will appear more retruded than it actually will be after the facial 
edema has resolved.
OUTCOME STABILITY IN ORTHOGNATHIC 
SURGERY
Excellent  stability  following  orthognathic  surgery  is  of  para-
mount importance for patient satisfaction and successful clini-
cal  practice.  This  goal  can  be  achieved  by  involving  accurate 
diagnosisincluding  TMJ  pathology  assessment,  predictable 
treatment planning,  stable pre-surgical orthodontics mechan-
ics,  precise  surgical  techniques,  and  appropriate  post-surgical 
management and retention.
Bailey and colleagues  state one of  the main problems with 
the  literature  on  orthognathic  surgery  stability86:  “The  vast 
majority of studies use statistics based on normal distribution 
to describe post treatment changes. With a normal distribution, 
the mean is  the most  likely  indicator of what a patient would 
experience,  and  the  clinician  tends  to  think  of  it  in  just  that  
way. But  if  essentially no change occurred  in  three-fourths of 
the patients who experienced change, the mean is highly mis-
leading  as  an  expectation  of  treatment  response.”  Although 
many good papers on orthognathic surgery are available today, 
readers  must  be  careful  of  the  methods  and  statistics  used  to 
guide  conclusions.  Because  the  clinician  should  know  from 
experience,  in  the patient’s mind, his or her  success or  failure 
means 100% and not an isolated event. A case series or even a 
clinical  trial  might  mislead  to  conclude  for  stability  of  the 
average  sample,  whereas  a  few  patients  experience  dramatic 
instability.
Mandibular Advancement
The stability of mandibular advancement has been studied with 
two-dimensional  lateral  cephalometric  analysis,  and  three-
dimensional surface analysis for several years now.86-96 There is 
no doubt that the BSSRO is the technique of choice for man-
dibular  advancement  because  it  does  not  require  bone  grafts 
relationship. Growth is usually in a horizontal vector or uncom-
monly a vertical vector.
Active condylar hyperplasia can be treated predictably in the 
mid-teen  years  with  high  condylectomies,  including  removal  
of  the  medial  and  lateral  condylar  poles,  recontouring  of  the 
remaining condylar head to conform to the fossa, and reposi-
tioning  of  the  articular  disk  over  the  remaining  head  of  the 
condyle,  usually  with  a  Mitek  anchor.  This  predictably  elimi-
nates  any  further  growth  of  the  mandible,  and  simultaneous 
orthognathic surgery can be carried out to correct the associ-
ated  jaw  deformities.  With  this  technique,  post-surgical  jaw 
function is typically very good.79-82
Condylar hyperplasia type 2 (osteochondroma of the condyle). 
Condylar hyperplasia type 2 is a relatively rare unilateral TMJ 
condition  but  is  the  most  common  neoplastic  condition  that 
can  occur  in  the  TMJ.  Growth  is  usually  in  a  vertical  vector 
creating a unilateral elongation of the face and jaws. This condi-
tion can occur at any age but most commonly develops in the 
teenage years. The abnormal condylar growth may be slow or 
rapid, and the presenting symptoms may include facial asym-
metry,  malocclusion,  ipsilateral  lateral  open  bite,  and  75%  of 
the time, a contralateral TMJ disk displacement occurs with the 
development  of  TMJ  symptoms.  The  condyle  can  grow  pre-
dominantly vertical (condylar hyperplasia type 2A) (see Figure 
74-59,  G-I),  without  or  with  increase  in AP width  (Figure 
74-59, J-L), or develop exophilic outgrowth from the condylar 
head  (condylar hyperplasia  type 2B)  (see Figure 74-59, M-O) 
that can occur vertically, medially, anteriorly, laterally, posteri-
orly, and usually can be identified by radiographic, CT, or MRI 
imaging. Two basic approaches can be used to correct this path-
ological  condition.  First,  perform  a  low  condylectomy  with 
recontouring of the lower portion of the condylar neck to func-
tion as a new condyle and reposition the articular disk over the 
“new” head and stabilize it. Then perform the indicated orthog-
nathic procedures (usually double jaw to get the best outcome 
functionally and esthetically) in the same operation. The second 
option  includes  performing  a  low  condylectomy  with  recon-
struction  of  the  condyle  using  a  sternoclavicular  graft,  costo-
chondral graft, or a total joint prosthesis. Perform other required 
orthognathic  procedures  in  the  same  operation  or  in  a  later 
operation. The contralateral TMJ may require a disk reposition-
ing procedure at the same time if the disk is displaced.80,82,83
Simultaneous Orthognathic Surgery and Rhinoplasty
Nasal airway difficulties usually can be corrected at the time of 
the  orthognathic  surgery,  while  the  maxilla  is  mobilized  and 
rotated inferiorly. This gives good access to perform nasal sep-
toplasty, partial turbinectomy, removal of nasal polyps, or other 
indicated  procedures.  External  nasal  deformities  can  be  cor-
rected  at  the  same  time  as  the  orthognathic  surgery  or  at  a 
secondary procedure. For some patients,  it may be more con-
venient and practical to carry out the rhinoplasty procedures at 
the same time as the orthognathic surgery.84,85 The use of rigid 
fixation for the orthognathic surgery is paramount because of 
the necessity to maintain a good oral airway, because the nasal 
airway often  is obstructed with mucous, packing,  edema, and 
blood  clots,  rendering  it  ineffective  as  an  airway  immediately 
after  surgery  and  for  a  few  more  days.  Surgical  sequencing 
includes performing all of the orthognathic surgery with appli-
cation  of  rigid  fixation  first  using  a  nasal  endotracheal  tube. 
Two basic approaches to airway management are available when 
performing  the  required  change  from  the  nasoendotracheal 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1089
previous TMJ pathology and mandibular advancements larger 
than 7 mm.
The  largest group of Class  II patients  to seek orthognathic 
surgery  have  a  high  occlusal  plane  angle  facial  profile  and  
most  frequently  they  require  double  jaw  surgery  including 
counterclockwise  rotation  of  the  occlusal  plane  and  signifi-
cantly larger mandibular advancement than 10 mm in order to 
achieve appropriate function and esthetics.54,107 It is well docu-
mented that these patients are much more susceptible to TMJ 
internal derangements and instability after maxillomandibular 
osteotomies  being  considered  as  problematic  in  the  stability 
studies.86,87,90,108-116
High occlusal plane angle  facial profile patients commonly 
have mouth breathing with nasal obstruction due to enlarged 
turbinates,  decreased  oropharyngeal  airway  space,  severe 
retruded mandible, and increased anterior facial height. Wolford 
and other groups have shown that maxillomandibular counter-
clockwise rotation with mandibular advancement stability will 
be dramatically affected by untreated pre-existing TMJ pathol-
ogy,  including  AICR,  reactive  arthritis,  autoimmune  and  
connective  tissue  diseases,  condylar  hyperplasia,  and  so  on.* 
Identification and appropriate treatment of the TMJ pathology 
is paramount  for predictable  treatment outcomes  for orthog-
nathic surgery.
A  patient  that  has  previous  TMJ  pathology  and  refuses  to 
have TMJ  surgery prior  to or  concomitant with orthognathic 
surgery  increases  significantly  the  risk  of  condylar  resorption 
following  maxillomandibular  counterclockwise  rotation  and 
mandibular advancement. In this situation, condylar resorption 
that can originate from different etiologies will lead to orthog-
nathic  surgery  relapse.  Figures  74-60  through  74-75  show  a 
16-year-old  female  patient  with  AICR  that  was  submitted  to 
maxillomandibular counterclockwise rotation and mandibular 
advancement and no TMJ surgery.  In preparation  for surgery 
(Figures 74-60 through 74-62), the patient was directed to avoid 
parafunctional  habits  and  nutritional  supplementation  was 
prescribed  (vitamin  C,  D,  and  E;  calcium;  and  omega-3  fatty 
acid).120 Cone beam CT surface model  superimposition dem-
onstrates  the  surgical  movements  involving  counterclockwiserotation of the maxillofacial complex and the immediate effect 
on the condyles (Figures 74-63 through 74-65). One year  fol-
lowing  surgery,  she  presented  with  acceptable  dental,  skeletal, 
and  facial  profile  stability  (Figure  74-66),  although  condylar 
resorption  was  occurring  (Figures  74-67  and  74-68),  creating 
skeletal relapse as seen with the cone beam CT superimposition 
on  the  immediate post-surgery and 1-year  follow-up  imaging 
(Figures 74-69 through 74-71). Further instability occurred at 
the second year of follow-up due to continued condylar resorp-
tion  and  consequent  clockwise  rotation  of  the  maxilloman-
dibular complex (Figures 74-72 through 74-75).
Mandibular  advancement  or  maxillomandibular  advance-
ment  (MMA)  stability  is  achieved  with  detailed  diagnosis, 
careful orthodontics and  surgical plan, precise execution, and 
long-term retention. Appropriate TMJ diagnosis and treatment 
should  be  done  before  or  simultaneous  with  orthognathic 
surgery in order to offer predictable results. A successful treat-
ment plan, precise execution, and solid stability are presented 
for this 16-year-old female with AICR, but the TMJ pathology 
and  allows  for  internal  rigid  fixation  (IRF)  in  several  distinct 
intraoral  and  extraoral  protocols.  There  is  some  controversy 
between the use of bicortical screws or bone plates and mono-
cortical  screws  as  the  best  method  of  fixation.97-99  Although 
both methods can accomplish the goal, the inclusion of bicorti-
cal screws can increase effectiveness of IRF mechanical proper-
ties  and  decrease  the  possibility  of  pseudarthrosis  and  earlier 
release of intermaxillary elastics.99 The negative factors of its use 
are  the  extraoral  approach  for  posterior  drilling  and  screw 
insertion  through  a  transcutaneous  trocar,  possible  condylar 
torque,  and  increased  risk  of  damage  to  the  inferior  alveolar 
nerve.  Condylar  torque  is  probably  the  major  concern  of  the 
use  of  bicortical  screws  following  BSSRO  and  related  to  the 
higher rates of  long-term instability compared with miniplate 
methods.  This  observation  is  probably  influenced  by  the  
fact  that  larger  mandibular  advancement  is  more  frequently 
reported with bicortical  screws and by  the greater number of 
clinical trials compared with miniplate fixation methods.97
It is well known that increased loading is potentially harmful 
for any body joint mainly with previous pathologies associated. 
Condylar  torque  can  be  minimized  with  careful  surgery  in 
experienced  hands,  use  of  osteotomy  design  that  improves 
precise  bone  contact  and  visualization  of  bone  interferences, 
removal  of  all  bone  interferences,  use  of  positional  bicortical 
screws after appropriate tapping, use of passive method/device 
to hold proximal and distal segments in place without compres-
sion,  and  use  of  bone  plate  fixed  with  monocortical  screws 
inserted  prior  to  bicortical  screws  insertion.100,101  Although 
experience and proper technique can make a difference, some 
condylar  torque  will  occur  after  large  mandibular  advance-
ments and counterclockwise rotation of the occlusal plane angle 
regardless  of  the  technique  used.92,94,96,102  This  is  a  matter  of 
physics principles that states: Two solid objects cannot be in the 
same place at the same time. Due to the anatomy of the man-
dible in a parabolic format with the larger width at the posterior 
region, it is obvious that large mandibular advancement might 
promote  some  condylar  torque  despite  the  use  of  bicortical 
screws or not. We have shown that although condylar torque is 
harmful  to  TMJs,  post-surgical  condylar  resorption  is  mostly 
related  to  previous  TMJ  pathologies  instead.91,96,103  A  recent 
clinical  case  presentation  has  shown  a  patient  with  greater 
amount  of  TMJ  condylar  resorption  on  the  side  where  less 
condylar torque was observed and more aggressive TMJ pathol-
ogy was present prior to surgery.103
Other  factors  influencing  relapse  following  mandibular 
advancement  include  the  amount  of  advancement,  type  and 
material  of  fixation,  low  and  high  mandibular  plane  angle, 
spatial  control  of  proximal  segment,  soft  tissue  and  muscle 
activity,  remaining  growth  and  remodeling,  preoperative  age, 
and  surgeon  skills.97,104,105  Mandibular  advancement  has  been 
considered  a  stable  procedure  on  the  hierarchy  of  stability 
studies.86,87,90  However,  such  stability  was  related  to  single  jaw 
surgery, mandibular advancement smaller than 10 mm, and for 
patients with short or normal face height only. A recent study 
that  addressed  the  stability  of  mandibular  advancement  with 
and without advancement genioplasty concluded that both pro-
cedures are clinically stable and emphasized lack of suprahyoid 
musculature influence.106 The conclusions of this study seem to 
be beyond the scope of  its methods and study design because 
the  sample  selection  and  surgical  changes  were  very  specific 
(not  very  common)  and  of  low  risk  of  relapse.  They  did  not 
determine  hyoid  bone  position  and  excluded  patients  with  *References: 15, 91, 105, 107, 117-119.
Text continued on p. 1095
1090 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-60 A to E, A 16-year-old female with adolescent internal condylar resorption (AICR) 
submitted to maxillomandibular counterclockwise rotation and mandibular advancement, but 
with no temporomandibular joint (TMJ) surgery. 
A B
C D E
FIG 74-61 Magnetic resonance imaging (MRI) of right temporo-
mandibular joint (TMJ) of 16-year-old patient with adolescent 
internal condylar resorption (AICR). 
FIG 74-62 Magnetic resonance imaging (MRI) of left temporo-
mandibular joint (TMJ) of 16-year-old patient with adolescent 
internal condylar resorption (AICR). 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1091
FIG 74-63 A to C, Pre-surgery (white) and immediate post-surgery (red) cone beam computed 
tomography (CT) surface models with voxel-wise cranial bone superimposition showing the 
maxillomandibular surgical movements. 
A B C
FIG 74-64 Right condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of pre-surgery (white) and immedi-
ate post-surgery (red). Vector maps (bottom figures) show 
the direction and amplitude of displacement/remodeling in 
millimeters. 
FIG 74-65 Left condyle cone beam computed tomography 
(CT) surface models (front, top and back views) with voxel- 
wise cranial base superimposition of pre-surgery (white) and 
immediate post-surgery (red). Vector maps (bottom figures) 
show the direction and amplitude of displacement/remodeling 
in millimeters. 
1092 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-66 A to E, The patient is seen 1-year post-surgery showing the achievement of accept-
able facial balance and occlusion. 
A
C D E
B
FIG 74-67 Magnetic resonance imaging (MRI) of right temporo-
mandibular joint (TMJ) shows the progression of resorption of 
the right condyle. 
FIG 74-68 Magnetic resonance imaging (MRI) shows the pro-
gressive condylar resorption of the left condyle. 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1093
FIG 74-69 A to C, Immediate post-surgery (red) and 1-year follow-up (light blue) cone beam 
computed tomography (CT) surface models with voxel-wise cranial base superimposition. Note 
slight maxillomandibular counterclockwise rotation. 
A B C
FIG 74-70 Right condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of immediate post-surgery (red) 
and 1-year follow-up (light blue). Vector maps (bottom figures)show direction and amplitude of displacement/remodeling in 
millimeters. 
FIG 74-71 Left condyle cone beam computed tomography (CT) 
surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of immediate post-surgery (red) 
and 1-year follow-up (light blue). Vector maps (bottom figures) 
show direction and amplitude of displacement/remodeling in 
millimeters. 
1094 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-72 A to E, The patient is seen 2 years post-surgery with significant change in facial profile 
with the mandible becoming significantly more retruded. Occlusion has remained reasonably 
stable, although there is a slight tendency for the bite to open. 
A
C D E
B
FIG 74-73 A to C, Immediate post-surgery (red) and 25-month follow-up (blue) cone beam com-
puted tomography (CT) surface models with voxel-wise cranial base superimposition. Note sig-
nificant maxillomandibular clockwise rotation. 
BA C
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1095
characteristics,  as  well  as  the  proven  treatment  protocols  that 
will provide predictable and stable results.
Common Temporomandibular Joint Pathologies that 
Adversely Affect Orthognathic Surgical Outcomes
Magnetic Resonance Imaging Evaluation
MRI is one of the most important diagnostic tools that we have 
in evaluation and diagnoses of TMJ pathology. In general, T1 
MRIs  are  helpful  in  identifying  disc  position,  the  presence  of 
alteration in bone and soft tissue structures structure, and inter-
relationships of the bony and soft tissue anatomy. T2 MRIs are 
more helpful in identifying inflammatory responses in the TMJ. 
The  importance  of  disc  position  cannot  be  overemphasized.  
In  our  study,  we  evaluated  three  different  patient  groups  
that  required  counterclockwise  rotation  and  advancement  of 
the maxillomandibular complex.11 The three groups were well 
matched relative to the amount of advancement at menton of 
approximately 13 mm in a counterclockwise direction. Group 
1 had healthy TMJ joints with the articular discs in position and 
had only orthognathic surgery performed. Group 2 had anteri-
orly  displaced  articular  discs,  and  at  surgery  these  discs  were 
repositioned into a normal relationship with the Mitek anchor 
technique and CTOS performed. Group 3 had anteriorly dis-
placed discs but only had orthognathic surgery performed. At 
longest  follow-up  with  an  average  of  31  months,  the  average 
relapse at menton for Group 1 with the healthy joints was 5%, 
or  0.5  mm  for  every  10  mm  of  maxillomandibular  counter-
clockwise  advancement.  Group  2,  who  had  displaced  discs 
repositioned with  the Mitek anchor  technique and orthogna-
thic  surgery had an average  relapse of 1%, or 0.1 mm per 10 
mm  of  counterclockwise  mandibular  advancement.  In  Group 
3, who had displaced discs where only orthognathic surgery was 
performed, the average AP relapse was 28% of the amount of 
advancement or almost 3 mm for every 10 mm of mandibular 
advancement,  indicating  post-surgical  condylar  resorption 
occurring  in  this  group  of  patients.  This  study  conclusively 
shows the importance of having the articular discs in position 
for  stability  in  orthognathic  surgery,  particularly  in  patients 
who require mandibular advancement and specifically for those 
that require counterclockwise rotation of the maxillomandibu-
lar  complex.  The  counterclockwise  rotation  of  the  maxillo-
mandibular complex is a very stable procedure if the discs are 
healthy and/or placed into proper anatomical position.
In a previous study, we evaluated 25 patients who had bilat-
eral  TMJ  displaced  articular  discs  and  underwent  double  jaw 
MMA surgery with an average advancement of 9 mm at point 
B,  but  the  TMJs  were  not  addressed,  so  the  articular  discs 
remained  anteriorly  displaced.15  At  pre-surgery,  36%  of  the 
patients had pain or discomfort  involving the TMJ, head, and 
jaw  area. At  an  average  of  2.2  years  post-surgery,  84%  of  the 
patients  had  pain.  The  average  pain  at  longest  follow-up 
increased 70% in  intensity over  the pre-surgical pain  level.  In 
addition, 30% of the patients developed significant mandibular 
AP relapse and developed open bites. This study also demon-
strates the adverse effect of performing orthognathic surgery on 
patients with displaced TMJ articular discs.
For  MRI  evaluation  of  the  TMJs,  the  basic  views  that  are 
most helpful in diagnoses include:
•  Sagittal  views  in  centric  relation  as  well  as  in  maximum 
opening
•  Coronal views in centric relation
•  Dynamic views, if available
FIG 74-74 Right condylar cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of immediate post-surgery (red) 
and 25-month follow-up (blue). Vector maps (bottom figures) 
show direction and amplitude of displacement/remodeling in 
millimeters. 
FIG 74-75 Left condyle cone beam computed tomography (CT) 
surface models (front, top and back views) with voxel-wise 
cranial base superimposition of immediate post-surgery (red) 
and 25-month follow-up (blue). Vector maps (bottom figures) 
show direction and amplitude of displacement/remodeling in 
millimeters. 
was  addressed  at  surgery  by  concomitant  TMJ  articular  disc 
repositioning  with  the  Mitek  anchor  technique  (see  Figure 
74-56) and double jaw orthognathic surgery with counterclock-
wise  rotation  of  the  maxillomandibular  complex  and  genio-
plasty (Figures 74-76 through 74-83).
This next section presents the common TMJ pathologies that 
affect orthognathic surgical outcomes, clinical and radiographic 
FIG 74-76 A to E, This 16-year-old female presented with bilateral temporomandibular joint (TMJ) 
adolescent internal condylar resorption (AICR) with progressive condylar resorption, retrusion of 
the mandible, and development of an anterior open bite. The patient was treated with bilateral 
TMJ articular disc repositioning with Mitek anchor, counterclockwise rotation of the maxilloman-
dibular complex with maxillary osteotomies and bilateral sagittal split osteotomies, genioplasty, 
and nasal turbinectomies. 
A
C D E
B
FIG 74-77 A, Magnetic resonance imaging (MRI) of right temporomandibular joint (TMJ) 
shows an anteriorly displaced disc and a condyle that is undergoing some resorption. B, MRI 
of left TMJ showing anteriorly displaced discs and presence of adolescent internal condylar 
resorption (AICR). 
A B
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1097
FIG 74-78 A to C, Pre-surgery (white) and post-surgery (red) cone beam computed tomography 
(CT) surface models with voxel-wise cranial base superimposition (T2 minus T1). 
A B C
FIG 74-79 Right condylar cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel- 
wise cranial base superimposition of pre-surgery (white) and 
immediate post-surgery (red)—T2 minus T1. Vector maps 
(bottom figures) show direction and amplitude of displacement/
remodeling in millimeters. 
FIG 74-80 Left condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel- 
wise cranial base superimposition of pre-surgery (white) 
and immediate post-surgery (red)—T2 minus T1. Vector maps 
(bottom figures) show direction and amplitude of displacement/
remodeling in millimeters. 
With a normal healthy condyle (Figure 74-84), the condyle 
should have a uniform shape and consistent thickness of cortical 
bone. The condyle should be positioned in the fossa with equal 
joint space between the condyle and fossa posteriorly, superiorly, 
and anteriorly. The articular disc should sit on top of the condyle 
with the posterior band being about the 12 o’clock position. The 
disc  should  have  a  bowtie  shape  with  increasedthickness  of  
the posterior band and anterior band and a thinner area for the 
intermediate zone. The articular eminence should have a mod-
erate inclination, although the articular eminence may be quite 
variable in its steepness, which in some cases can contribute or 
predispose to certain TMJ conditions. The MRI imaging can be 
correlated to cone beam imaging of the TMJs for joint space and 
greater interpretation of bony pathology.
Figure 74-84 demonstrates the sagittal view of a normal and 
healthy TMJ. On opening, there should be good translation of 
the  condyle  and  the  articular  disc  forward  and  positioned 
beneath the articular eminence. The most common direction of 
disc displacement is anterior and anteromedial. Upon opening, 
a click or pop may be heard at the TMJ as the condyle reduces 
over the posterior band and onto the disc (Figure 74-85).
Silent Temporomandibular Joint With Disc Displacement
There are a number of TMJ pathological processes where  the 
disc is displaced, but yet the disc is silent with function. These 
1098 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-81 A to E, At 2 years post-surgery, the patient maintains good facial balance and a good 
stable occlusion. 
A B
C D E
FIG 74-82 A to C, Immediate post-surgery (red) and 1-year follow-up (light blue) cone beam 
computed tomography (CT) surface models with voxel-wise cranial base superimposition (T3 
minus T2). 
A B C
situations include a steep articular eminence where the articular 
disc is anteriorly displaced but in a vertical orientation so that 
upon  opening  there  is  an  immediate  reduction  of  the  disc 
because  it  is  in  a “pre-click”  position.  Medial  and  lateral  dis-
placements of the disc may create pain and dysfunction, but the 
joints may be silent because there is no reduction over the pos-
terior band (Figure 74-86). This also goes along with posterior 
displaced discs where the TMJs may make no noise but could 
contribute to pain and discomfort (Figure 74-87).
Certain  pathological  conditions  such  as AICR  where  there 
may  be  thickening  of  the  bilaminar  tissues  so  that  there  is  a 
smooth transition from the thickened bilaminar tissue onto the 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1099
Adolescent Internal Condylar Resorption
AICR  has  a  relatively  classic  presentation.  This  condition  
develops usually between 11 to 15 years old, predominantly in 
females  (ratio  8 : 1  females  to  males).  Clinically,  the  mandible 
will be noted to slowly retrude into a Class II occlusal and skel-
etal relationship with a tendency toward anterior open bite (see 
Figures 74-60 and 74-76). These patients all have high occlusal 
plane angle facial morphological profiles. However, on the MRI 
(see Figure 74-61 and 74-62), these cases present with a condyle 
that may be slowly becoming smaller in size in all three planes 
of space. In some cases, there is significant thinning of the corti-
cal bone on top of the condyle contributing to the inward col-
lapse  of  the  condylar  head  in  this  pathological  process.  The 
articular  discs  are  anteriorly  displaced  and  may  or  may  not 
reduce  on  opening.  Non-reducing  discs  will  degenerate  and 
deform at a more rapid rate as compared to a disc that reduces. 
Our studies demonstrate that AICR is arrested if the articular 
discs are put back into position on top of the condyle and sta-
bilized with  the Mitek anchor  technique.121-123 A post-surgical 
view  of  a  repositioned  disc  with  a  Mitek  anchor  is  seen  in 
(Figure  74-89).  There  is  some  distortion  of  the  MRI  imaging 
because of the metal anchor in the head of the condyle, but the 
reduced position of the disc is noted. Results are best for AICR 
if the TMJ surgery is performed within 4 years of the onset of 
the  pathology. After  4  years,  the  discs  may  not  be  salvageable 
and  the  indicated  treatment  may  then  be  custom-fitted  total 
joint prostheses to repair the TMJs and advance the mandible.
Osteochondroma (Condylar Hyperplasia Type 2)
Osteochondroma (condylar hyperplasia type 2) will commonly 
present as an enlarged condyle with either extended exophytic 
growth off  the  condylar head  (Figure 74-90) versus  increased 
vertical dimension of the condylar head (see Figure 74-59, J-O). 
This condition is a unilateral TMJ pathological process, and the 
articular  disc  is  commonly  in  position,  even  in  the  presence  
of  large  exophytic  pathological  growth  processes.  However, 
importantly,  in  cases  with  condylar  hyperplasia  type  2,  often  
the contralateral “normal” joint may be overloaded, developing 
an  anteriorly  displaced  disc  and  subsequently  arthritic  
disc, thus no noise is made. Also in patients who have anteriorly 
displaced discs without reduction may have no noises (Figure 
74-88). Patients who have been in long-term splint therapy with 
downward and forward posturing of the mandible may create 
thickening  of  the  bilaminar  tissues  so  that  there  is  a  smooth 
transition onto the disc. Any Class II mechanics may artificially 
pull the condyle down and forward onto the disc, but this may 
be  an  unstable  position  that  the  surgeon  must  be  aware  of  
and  understand  that  orthognathic  surgeries  performed  with 
advancement of  the mandible will  likely position  the  condyle 
into a centric  relation post-surgery and  the disc will  again be 
anteriorly displaced.
FIG 74-83 Right condyle and left condyle cone beam computed 
tomography (CT) surface models (front, top, and back views) 
and voxel-wise cranial base superimposition on immediate 
post-surgery (red) and 1 year follow-up (light blue)—T3 minus 
T2. Vector maps (bottom figures) show direction and amplitude 
of displacement/remodeling in millimeters. 
FIG 74-84 A, Normal temporomandibular joint (TMJ) with posterior band of disc at 12 o’clock. 
B, On opening, the condyle and disc translate down and forward beneath the articular 
eminence. 
A B
Articular disc Articular disc
1100 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-85 A, In closed position, the condyle is positioned posterior in the fossa and the disc is 
anteriorly displaced. B, On opening, the disc reduces into a normal position. 
A
Articular disc
Articular disc,
Anteriorly
displaced in
centric relation
Articular disc,
reduced during
jaw opening
Articular disc
A B
FIG 74-86 A, Sagittal view of anteriorly displaced discs. B, In this coronal view, the articular disc 
is medially displaced. C, In this coronal view, the disc is laterally displaced. 
A B C
Anterior disc
displacement
Medially
displaced
disc
Lateral disc
displacement
FIG 74-87 In this case of condylar hyperplasia type 1, the 
condyle is growing vertically at an accelerated rate that is faster 
than the posterior ligament attachment can migrate upward, 
thus pulling the disc posterior to the condyle. 
Posterior disc
displacement
FIG 74-88 The articular disc is anteriorly displaced and signifi-
cantly deformed, degenerated, and nonreducing, rendering it 
nonsalvageable. 
Non-salvageable
Anteriorly displaced
articular disc
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1101
a  more  profuse  inflammatory  process  through  the  bilaminar 
tissues,  capsule  (Figure 74-91), and so on. Surgical  indication 
may be to go in and remove the nidus of inflammation versus 
extensive destruction of the joint that may require a total joint 
prosthesis.
Perforations
Perforations can occur  in  the TMJ area resulting  in bone-on-
bone contact. For perforations, the discs are usually displaced. 
Almost always, these perforations are posterior to the posterior 
band of the articular disc or lateral to the disc; rarely do perfora-
tions  occur  through  the  disc  itself  (Figure  74-92).  Relative  to 
changes, which occurs in about75% of the cases with a unilat-
eral  condylar  hyperplasia  type  2.  The  indicated  treatment 
includes a low condylectomy for removal of the tumor, recon-
touring of the condylar neck to form a new condyle, and repo-
sitioning of the articular disc, as long as the disc is salvageable, 
with a Mitek anchor technique, and the recontoured ipsilateral 
condylar neck will then function as a new condyle. The required 
orthognathic surgery procedure can be done concomitantly.
Reactive Arthritis
Reactive  arthritis  may  show  a  localized  area  of  inflammation 
with erosion of the condyle and/or fossa. It also can present as 
FIG 74-89 Magnetic resonance imaging (MRI) demonstrates a 
repositioned articular disc using the Mitek anchor technique 
with the disc in a normal position. 
Mitek anchor
Articular disc,
repositioned
with Mitek
anchor
technique
FIG 74-90 Magnetic resonance imaging (MRI) scan of right 
temporomandibular joint (TMJ) shows an osteochondroma with 
large exophytic growth of the anterior aspect of the condyle 
(condylar hyperplasia type 2B). The articular disc is in favorable 
position and salvageable. 
Right condylar
osteochondroma
Articular disc in
favorable position
and condition
FIG 74-91 T2 magnetic resonance imaging (MRI) scan of right 
temporomandibular joint (TMJ) with reactive arthritis and con-
dylar resorption. The inflammatory process is noted to occupy 
a significant volume between the fossa and condyle. The disc 
is not identifiable. 
FIG 74-92 Magnetic resonance imaging (MRI) of left condyle 
with perforation of the bilaminar tissue posterior to the articular 
disc. Bone-to-bone contact of condyle and fossa is observed 
with crepitation on jaw function. 
Bone to bone contact
of condyle and fossa
Articular disc
with perforated
lateral
attachment
Condyle
1102 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
articular disc dislocation and arthritis from the increased func-
tional loading on that joint related to the over-development of 
the  ipsilateral  side. Unilateral condylar under-development or 
resorption  can  cause  the  mandible  and  face  to  be  smaller  on 
one side and the jaws to shift toward the involved side. Perform-
ing  orthognathic  surgery  only  in  facial  asymmetry  cases  and 
ignoring the TMJs during treatment or failure to render proper 
TMJ management can result in the dentofacial asymmetry and 
malocclusion  redeveloping  with  worsening  TMJ-associated 
symptoms including jaw dysfunction and pain.
Age for Surgical Intervention
Although there are  individual variations,  females usually have 
the majority of their facial growth (98%) complete by 15 years 
old and males by 17 to 18 years old.125 Predictability of results 
and limiting correction of the jaw and TMJ pathology–related 
deformities  to  one  major  operation  can  best  be  achieved  by 
waiting until growth is relatively complete. However, there are 
definite indications for performing surgery during the growing 
years, such as progressive TMJ deterioration, ankylosis, require-
ments for growth center transplants (i.e., rib or sternoclavicular 
grafts),  masticatory  dysfunction,  tumor  removal,  pain,  sleep 
apnea, and so on. Performing surgery during growth may result 
in  the  need  for  additional  surgery  at  a  later  time  to  correct  a 
resultant deformity and malocclusion that may develop during 
the completion of growth. In addition, some orthognathic sur-
gical  procedures  have  a  profound  effect  on  subsequent  facial 
growth and development, including maxillary Le Fort I osteoto-
mies. We have previously published on maxillary and mandibu-
lar  surgery  and  the  effects  on  growth  with  guidelines  for  age 
considerations for surgical intervention, as well as TMJ surgery 
effects on facial growth.44-46,126
Adolescent Internal Condylar Resorption
Etiology. AICR, formerly referred to in the generic terminol-
ogy as idiopathic condylar resorption, is one of the most common 
TMJ conditions affecting teenage females.117,121-123 AICR is also 
known as cheerleader syndrome, idiopathic condylysis, condylar 
atrophy,  and  progressive condylar resorption.  AICR  is  a  well-
documented  disease  process  occurring  with  an  8 : 1  female  to 
male  ratio,  onset  between  11  to  15  years  old  during  pubertal 
growth and development, and is rarely initiated before 11 years 
old or after 15 years old.117,121-123 There are other local and sys-
temic  pathologies  or  diseases  that  can  cause  condylar  resorp-
tion, but AICR is a specific disease entity different from all of 
the other disease processes and can create occlusal and muscu-
loskeletal instability resulting in the development of a dentofa-
cial deformity, TMJ dysfunction, and pain.
Although  the  specific  cause  of  AICR  has  not  been  clearly 
identified,  its  strong  predilection  for  teenage  females  in  their 
pubertal growth phase supports a theory of hormonal media-
tion.  Estrogen  receptors  have  been  identified  in  the  TMJs  of 
female  primates,  human  TMJ  tissues,  and  in  arthritic  knee 
joints.127-129  Estrogen  is  known  to  mediate  cartilage  and  bone 
metabolism  in  the  female  TMJ.130,131  An  increase  in  receptors 
may predispose an exaggerated response to joint loading from 
parafunctional activity, trauma, orthodontics, or orthognathic 
surgery.
The  authors’  hypothesis  for  this  TMJ  pathology  is  that  
female hormones mediate biochemical changes within the TMJ, 
causing  hyperplasia  of  the  synovial  tissues  that  stimulate  the 
production of destructive substrates that initiate breakdown of 
the condyle, perforations can occur in the middle, medially, or 
laterally. Clinically, crepitation will usually be present; and on 
the MRI, there will be evidence of bone-on-bone contact and 
usually arthritic evidence on the condylar head and/or fossa.
Connective Tissue/Autoimmune Diseases
The  MRI  presentation  of  connective  tissue/autoimmune  dis-
eases is fairly pathognomonic. In these conditions, the articular 
disc oftentimes is in the normal position, but there is progres-
sive  condylar  resorption and  often  resorption  of  the  articular 
eminence with slow but progressive destruction of the articular 
disc  that  is  surrounded  by  a  reactive  pannus  (Figure  74-93). 
This presentation almost always indicates the requirement of a 
total  joint  prosthesis  for  jaw  reconstruction  to  eliminate  the 
pathologic process in the joint. Use of autogenous tissues in this 
scenario  could  result  in  the  disease  process  attacking  autoge-
nous tissues placed into the joint with subsequent failure.
Nonsurgical and Closed Treatment Considerations
Nonsurgical TMJ treatments (e.g., splints, physical therapy, chi-
ropractic  treatment,  orthodontics,  biofeedback,  acupuncture, 
and  medications)  may  help  the  TMJ  symptoms  but  do  not 
stabilize  and  eliminate  TMJ  disorders  (e.g.,  disc  dislocation, 
arthritis, condylar resorption, or condylar hyperplasia) to with-
stand  the  increased  TMJ  loading  that  usually  accompanies 
orthognathic surgery. Arthrocentesis and arthroscopy are con-
traindicated  in patients with TMJ disorders requiring orthog-
nathic surgery, because these techniques do not reposition and 
stabilize the articular disc in a normal position but may convert 
a reducing disc into a nonreducing disc that will yield a more 
rapid deformation and degeneration process of the disc, subse-
quently rendering it nonsalvageable.
Temporomandibular Joint and Facial Asymmetry
Facial  asymmetries  are  commonly  caused  by  TMJ  pathology 
and can create a progressive worsening of the facial deformity 
and malocclusion.124 For example, a unilateral condylar patho-
logical over-development of the condyle can cause facial asym-
metry  and  affect  the  contralateral “normal”  TMJ  by  creating 
FIG 74-93 Common temporomandibular joint (TMJ) changes in 
connective tissue/autoimmunedisease. The disc is in position, 
but with a reactive pannus (gray tissue) surrounding the disc 
that destroys the disc, condyle, and articular eminence. 
Reactive pannus
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1103
Treatment options. When the discs are still  salvageable, our 
treatment protocol has proven to eliminate this TMJ pathology 
and  allow  optimal  correction  of  the  associated  dentofacial 
deformity  at  the  same  operation.  The  protocol  includes  the 
following62,117,121,123,132-135:
1.  Remove the bilaminar tissue surrounding the condyle.
2.  Mobilize, reposition, and stabilize the disc to the condyle with 
a Mitek anchor and artificial ligaments (see Figure 74-56).
3.  Perform the indicated orthognathic surgery (usually double 
jaw)  with  counterclockwise  rotation  of  the  maxillo-
mandibular complex.
4.  Other adjunctive procedures that are indicated (see Figures 
74-76 through 74-83).
Because  this  high  occlusal  plane  angle  facial  morphology  
is  commonly  associated  with  decreased  oropharyngeal  airway 
space  and  sleep  apnea,  the  counterclockwise  rotation  of  the 
maxillomandibular complex will also maximize the AP dimen-
sion  of  the  oropharyngeal  airway,  eliminating  sleep  apnea 
symptoms.  In  growing  patients,  this  approach  not  only  stops 
the condylar resorption, but mandibular condylar growth will 
begin again.117,121 Results are best for AICR if the TMJ surgery 
is  performed  within  4  years  of  the  onset  of  the  pathology.  
After  4  years,  the  discs  may  become  significantly  deformed  
and degenerated so as not to be salvageable; then the indicated 
treatment  would  be  patient-fitted  total  joint  prostheses  (TMJ 
Concepts) to repair the TMJs and advance the mandible.
Although this AICR surgical protocol has been successful for 
more than 20 years, some controversy still remains in the litera-
ture, specifically in regard to the possible side-effects related to 
open joint surgery and condylar changes afterwards.136-138 In an 
ongoing  study,  we  are  assessing  three-dimensional  condylar 
changes occurring  1  year  after  surgery  in  two patient  groups: 
Group  1  consists  of  young  adult  patients  with  normal  TMJs  
that  had  MMA  only,  and  group  2  consists  of  young  adult  
AICR  patients  with  MMA  and  articular  disc  repositioning 
(MMA-Drep).  For  each  patient,  cone  beam  CTs  were  seg-
mented  in  a  semi-automatic  protocol  and  registered  in  a  
rigid, voxel-wise automatic algorithm over the cranial base.139-141 
Three  distinct  methods  were  used  to  assess  the  condyles 
three-dimensionally:
1.  Surface  shape  correspondence  using  the  SPHARM-PDM 
package142,143
2.  Subjective analysis of semi transparency overlays91,141,144,145
3.  Condylar volume estimation using ITK-Snap software90,91
The values  for  the voxels  in  each  tomographic  image were 
obtained  in  Hounsfield  units,  representing  the  opacity  of  
the x-rays.
Our  preliminary  results  showed  that  at  1  year  following 
surgery  AICR  patients  (MMA-Drep)  had  increased  condylar 
volume  compared  to  patients  with  healthy  TMJs  with  
MMA  only  that  experienced  a  reduction  of  condylar  volume  
(p <0.01).96
Reactive (Inflammatory) Arthritis
Etiology. Reactive arthritis (also called  seronegative spondy-
loarthropathy) is an inflammatory process in joints commonly 
related  to  bacterial  or  viral  factors.  This  condition  reportedly 
occurs  during  the  third  to  fourth  decade  of  life,  but  it  can 
develop at any age. In the TMJ, it more commonly develops in 
the  late  teens  through  the  fourth decade. Commonly,  reactive 
arthritis is seen in conjunction with a displaced TMJ articular 
disc, but it also can develop with the disc in position.
the ligamentous structures that normally support and stabilize 
the articular disc to the condyle. This allows the disc to become 
anteriorly  displaced.  The  hyperplastic  synovial  tissue  then  
surrounds  the  head  of  the  condyle.  The  substrates  penetrate 
through  the outer  surface of  the condyle and causes  thinning 
of the cortical bone and breakdown of the subcortical bone. The 
condyle slowly collapses, shrinking in size in all three planes as 
a result of internal condylar bone resorption without clinically 
apparent destruction of the fibrocartilage on the condylar head 
and  roof  of  the  fossa;  unlike  the  other  arthritic  conditions, 
where  the  fibrocartilage  and  cortical  bone  are  destroyed  by  
an  inflammatory,  connective  tissue,  or  autoimmune  disease 
process. AICR can progress for a while and then go into remis-
sion or proceed on until the entire condylar head has resorbed. 
In  cases  where  it  goes  into  remission,  excessive  joint  loading 
(i.e., parafunctional habits, trauma, orthodontics, orthognathic 
surgery, and so on) can reinitiate the resorption process. AICR 
usually occurs bilaterally with symmetrical condylar resorption, 
but facial asymmetry can occur if one side resorbs faster than 
the other or with only unilateral TMJ involvement.
Clinical features. AICR  has  classic  clinical  features  that 
include the following:
•  Initiated  during  pubertal  growth  (11  to  15  years  old)  pre-
dominately in teenage females (8 : 1 female to male ratio)
•  Progressive  worsening  skeletal  and  occlusal  deformity 
although occurring at a slow rate (average rate of condylar 
resorption is 1.5 mm per year)117,121
•  High occlusal plane angle facial morphology, Class II occlu-
sion with or without an anterior open bite
•  May  be  associated  with  TMJ  symptoms,  such  as  clicking, 
TMJ  pain,  headaches,  myofascial  pain,  earaches,  tinnitus, 
vertigo, and so on; however, 25% of patients with AICR have 
no overt symptoms
•  Jaw and jaw joint dysfunction
•  No  other  joint  or  systemic  involvement  (see  Figures  74-60 
and 74-76)117,121
Because AICR is normally initiated during pubertal growth, 
condylar resorption that originates prior to 11 years old or after 
15 years old is usually not AICR but a different TMJ pathology 
and  may  need  a  different  treatment  protocol.  AICR  rarely 
occurs in low occlusal plane angle (brachiocephalic) facial types 
or in Class III skeletal relationships. All cases are isolated occur-
rences with no genetic correlation.
Imaging. Radiographic features include the following:
•  Progressive decrease of condylar size and volume
•  Some cases have thinning cortex on top of the condyle
•  Can present with  increased, normal, or decreased  superior 
joint space
•  Decreased vertical height of the ramus and condyle
•  High occlusal plane angle facial morphology
•  Skeletal  and  occlusal  Class  II  relationship  (see  Figure  
74-3, A)
A normal MRI is seen in Figure 74-84. An MRI of AICR (see 
Figures 74-60 and 74-61) will show the following:
•  The  articular  disc  is  anteriorly  displaced  and  commonly 
becomes  nonreducing  relatively  early  in  the  pathological 
process (nonreducing discs have an accelerated rate of defor-
mation and degeneration compared to discs that reduce)
•  Condyle gets progressively smaller in three dimensions
•  Amorphous-appearing  tissue  may  surround  the  condyle, 
with or without an increased joint space
•  No inflammatory process seen
1104 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
Imaging. Radiographic features of reactive arthritis-causing 
condylar resorption can include:
•  Loss of vertical dimension and volume of the condyle
•  Articular surface of the condyle may be eroded with loss of 
the fibrocartilage covering the condyle and fossa
•  Retruded mandible
•  Class II occlusion with anterior open bite
•  Decreased vertical height of the ramus and condyle
MRI will commonly show:
•  Articular disc anteriorly displaced or in normal position
•  Joint effusion and inflammation in T2 imaging•  Resorbing condyle
•  Condylar  and  fossa  erosions  in  advanced  conditions  (see 
Figure 74-91)
Treatment options. The  approach  to  treating  this  TMJ 
pathology and associated deformity depends on  the  length of 
time  that  the  pathology  has  been  present,  the  amount  of 
destruction to the disc and condyle at the time of surgery, and 
the presence of other joint involvement (polyarthritis) or other 
related systemic conditions. If  the TMJ condition is  identified 
within the first 4 years of the onset of the disc dislocation, the 
destruction  is  not  significant,  and  there  are  no  other  joints  
or  systemic  conditions  present,  then  removing  the  bilaminar 
tissues around the condyle and repositioning the articular disc 
with the Mitek anchor technique may work well, preserving the 
normal anatomical structures (see Figure 74-56).62,123,132-135 It is 
possible that the resection and removal of a large portion of the 
bilaminar tissue (where it  is known that these bacteria reside) 
during surgery may result in a major reduction of the source of 
the inflammation. The orthognathic surgery can be done at the 
same surgery as the joints are repaired.
If there is significant destruction of the condyle and the disc 
is  not  salvageable,  or  polyarthritis  or  systemic  disease  are 
present,  then  the most predictable  treatment procedure  is  the 
patient-fitted  total  joint  prosthesis  (TMJ  Concepts)  to  recon-
struct the TMJ as well as reposition the mandible to its proper 
position (see Figure 74-32).72,74,151-154 Fat grafts packed around 
the total joint prosthesis are an important component to help 
prevent fibrous tissue and heterotopic bone from forming.146,147
Trauma
Traumatic  injuries  to  the  jaws  may  create  facial  deformities 
particularly involving the TMJs with unilateral or bilateral con-
dylar  or  subcondylar  fractures  that  are  inadequately  reduced. 
Patients may present with:
•  Mandible  retruded  or  deviated  toward  the  affected  side  if 
unilateral
•  Pain and jaw dysfunction
•  May  exhibit  deficient  growth  on  the  affected  side(s)  in 
growing patients
•  Class II skeletal and occlusal relationships
•  Premature  contact  of  the  occlusion  on  the  affected  side(s) 
with possible open bite and on the contralateral side
Imaging features could include:
•  Evidence  of  previous  condylar,  mandibular,  or  midfacial 
fractures
•  The condyle, when fractured, may be malpositioned down-
ward, forward, and medial to the fossa
•  Decreased vertical ramus/condyle length; MRI will also show 
the disc position and condition
At  the  initial  presentation  of  the  trauma,  the  options  for 
treating  subcondylar  fractures  are  open  reduction,  closed 
Henry  and  colleagues  demonstrated  that  73%  of  patients 
with  TMJ  articular  disc  displacements  have  bacteria  in  the 
bilaminar  tissues.146,147  The  bacterial  species  that  we  have 
identified  in  the  TMJ  include  Chlamydia trachomatis  and 
Chlamydophila psittaci,  as  well  as  Mycoplasma genitalium  and 
Mycoplasma fermentans.146-149  Other  bacteria  that  have  been 
found in other joints but also may infect the TMJ include Bor-
relia burgdorferi  (Lyme’s  disease),  Salmonella  species,  Shigella 
species,  Yersinia enterocolitica,  and  Campylobacter jejuni.  We 
suspect  that  other  bacterial/viral  species  may  cause  reactive 
arthritis  in  joints,  including  Chlamydia pneumoniae, Myco-
plasma pneumoniae, Ureaplasma urealyticum,  herpes  virus, 
Epstein-Barr virus, cytomegalovirus, Varicella zoster virus, and 
so  on.  Kim  and  colleagues  analyzed  TMJ  synovial  fluids  for 
specific bacteria and found M. genitalium and M. fermentans/
orale, as well as Staphylococcus aureus, Actinobacillus actinomy-
cetemcomitans,  and  Streptococcus mitis  present  in  86%,  51%, 
37%, 26%, and 7% of samples respectively.150 They did not test 
for the Chlamydia species.
Chlamydia  and  Mycoplasma  bacterium  species  live  and 
function  like  viruses;  and  therefore,  antibiotics  may  not  be 
effective  in  eliminating  these  bacteria  from  joints  and  the  
body. Antibiotics may affect the extracellular organisms but will 
not affect the intracellular bacteria, although the microbes may 
be  placed  into  a  dormant  state.  These  bacteria  are  known  to 
stimulate the production of Substance P, cytokines, and tissue 
necrosis factor, which are all pain modulating factors and con-
tribute  to  the  destruction  of  the  bone  and  cartilage  of  the 
joint.146-149 In addition, these bacterial species have been associ-
ated  with  Reiter’s  syndrome  and  dysfunction  of  the  immune 
system.
We also have identified specific genetic factors, human leu-
kocyte  antigen  (HLA)  markers  that  occur  at  a  significantly 
greater  incidence  in  TMJ  patients  than  the  normal  popula-
tion.149 These same markers also may indicate an immune dys-
functional  problem  for  these  bacterial  species,  allowing  the 
bacteria to have a greater effect on patients with these markers 
compared to people without these same markers.
Patients with localized TMJ reactive arthritis may have dis-
placed discs, pain, TMJ and jaw dysfunction, headaches, and ear 
symptoms. As the disease progresses, condylar resorption and/
or bony deposition can occur, causing changes in the jaw and 
occlusal relationships. Patients with moderate to severe reactive 
arthritis may have other body systems  involvement,  including 
the  genitourinary,  gastrointestinal,  reproductive,  respiratory, 
cardiopulmonary,  ocular,  neurological,  vascular,  hemopoietic, 
and immune systems, as well as involvement of other joints.
Clinical features. Although this condition commonly occurs 
bilaterally, it can occur unilaterally. In some patients, there may 
not  be  any  significant  condylar  resorption  and  therefore  may 
not have an adverse effect on facial morphology or occlusion. 
However, when causing condylar resorption, the following fea-
tures may be observed:
•  Mandible may become progressively retruded
•  Progressive worsening jaw and occlusal deformity, although 
it may occur at a slow rate
•  Class  II  occlusion  and  anterior  open  bite  with  premature 
contact on the posterior teeth
•  Common  associated  TMJ  symptoms  may  include  clicking, 
popping,  crepitus,  TMJ  dysfunction  and  pain,  headaches, 
myofascial pain, earaches, tinnitus, vertigo, and so on
•  Other joints and body systems may be involved
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1105
reduction, or no treatment. The amount of displacement and 
the condition of the fracture(s) will dictate the necessary treat-
ment to fix the problem. When identified early,  fractures may 
be  best  treated  by  open  reduction  for  significantly  displaced 
segments or closed reduction for minimally displaced segments 
to achieve a symmetric face and stable occlusion. If the condyle 
is  minimally  to  moderately  displaced,  still  salvageable  along 
with its articular disc but already healed, then it is possible that 
orthognathic surgery could realign the jaw structures properly, 
and if the disc is displaced, it can be repositioned with a Mitek 
anchor (see Figure 74-56). If the condyle is severely deformed 
and  nonsalvageable,  then  the  most  predictable  method  for 
reconstruction  of  the  TMJ  is  using  custom-fitted  total  joint 
prostheses  (TMJ  Concepts)  (see  Figure  74-32),  TMJ  fat  graft, 
and repositioning of the mandible if there is an associated man-
dibular malalignment. Other treatment options for TMJ recon-
struction are rib grafts, sternoclavicular grafts, and so on. But 
these outcomes are not as predictable as a custom-fitted  total 
joint prosthesis.
Temporomandibular Joint Ankylosis
TMJ  bony  ankylosis  usually  develops  as  a  result  of  trauma, 
inflammation, sepsis, and/or systemic diseases causing severely 
limitedjaw  function,  as  well  as  oral  hygiene  and  nutritional 
problems.  When  this  condition  occurs  during  the  growing 
years,  it  can  severely  affect  jaw  growth  and  development.  In 
unilateral ankylosis, the other condyle will continue to grow but 
may be retarded in its true growth potential. The common clini-
cal and radiographic characteristics of TMJ ankylosis, particu-
larly when occurring in children, include decreased jaw mobility 
and  function,  decreased  growth  on  the  involved  side,  facial 
asymmetry if unilateral involvement with the mandible shifted 
toward the ipsilateral side, retruded mandible, usually a Class II 
occlusion, and radiographic and MRI evidence of bony anky-
losis  between  the  condyle  and  the  fossa  or  heterotopic  bone 
surrounding the joint.
The  most  predictable  treatment  for  the  ankylosed  TMJ 
patient includes75,76:
•  Release  of  the  ankylosed  joint;  removal  of  the  heterotopic 
and  reactive  bone  with  thorough  débridement  of  the  TMJ 
and adjacent areas
•  Reconstruct  the TMJs  (and  if  indicated, advance  the man-
dible) with a custom-fitted total joint prosthesis
•  Coronoidotomies  or  coronoidectomies  if  the  ramus  is  
significantly  advanced  or  vertically  lengthened  with  the 
prosthesis
•  Autogenous  fat  graft  (harvested  from  the  abdomen  or 
buttock) packed around the prosthesis in the TMJ area
•  Additional orthognathic surgery if indicated; in these cases, 
it is absolutely necessary that fat grafts be packed around the 
articulating  parts  of  the  prosthesis  to  prevent  the  reoccur-
rence of heterotopic and reactive bone, as well as minimize 
fibrosis
Other techniques that have been advocated for reconstruc-
tion of TMJ ankylosis include using autogenous tissues, such as 
temporal  fascia  and muscle flaps, dermis-fat  grafts,  rib grafts, 
sternoclavicular  grafts,  vertical  sliding  osteotomy,  gap  arthro-
plasty,  and  so  on.  The  total  joint  prosthesis  with  a  fat  graft 
packed around it is a superior technique relative to prevention 
of re-ankylosis, providing jaw and occlusion stability, improv-
ing function and facial balance, and eliminating or decreasing 
pain.75,76 When treating young growing patients (10 years old or 
older), the custom-fitted total joint prosthesis with fat graft may 
still  be  the  best  option  to  eliminate  the  ankylosis.  However, 
because there would be no growth potential on the  ipsilateral 
side of the mandible (there is also no growth potential with a 
bony ankylosis), orthognathic surgery will  likely be necessary, 
but  it  can  be  delayed  until  the  patient  has  most  of  the  facial 
growth  complete  (females  15  years  old;  males  17  to  18  years 
old). Then double jaw orthognathic surgery can be performed, 
including a ramus sagittal split on the side of the prosthesis to 
reposition  the  jaws  into  the  best  alignment,  or  the  ipsilateral 
side can be advanced by repositioning the mandibular compo-
nent of the prosthesis or fabrication of a new, longer mandibu-
lar component.
Congenital Deformed/Absent Temporomandibular Joint 
(Hemifacial Microsomia)
There  are  hundreds  of  congenital  syndromes  that  can  cause 
facial deformities. Hemifacial microsomia (HFM) is one of the 
more common syndromes. Clinical  and radiographic  features 
of HFM usually include unilateral hypoplasia or aplasia of the 
mandibular condyle, ramus, and body, as well as hypoplasia of 
the  maxilla,  zygomatico-orbital  complex,  and  temporal  bone; 
decreased ipsilateral  facial height; retruded mandible deviated 
toward  the  ipsilateral  side;  Class  II  malocclusion;  transverse 
cant in the occlusal plane and skeletal structures; significant soft 
tissue deficiency on the involved side affecting muscles, subcu-
taneous tissues, and skin volume; and decreased oropharyngeal 
airway. With growth, the facial deformity, asymmetry, and mal-
occlusion usually worsen.
Approximately  one-third  of  the  HFM  cases  will  have  dis-
placed articular discs on the contralateral  side. These patients 
should  be  evaluated  for  this  concomitant  occurrence,  and  a 
TMJ MRI study will be warranted for the diagnosis. Our treat-
ment protocol for managing HFM for patients 14 years old or 
older  who  have  significant  hypoplasia  or  absence  of  the  TMJ 
includes the following:
•  Ipsilateral  TMJ  reconstruction  and  mandibular  advance-
ment  with  custom-fitted  total  joint  prostheses  (see  
Figure 74-32)
•  Contralateral  disc  repositioning  with  Mitek  anchor  (see 
Figure 74-56)
•  Contralateral ramus sagittal split osteotomy to advance the 
mandible
•  Multiple maxillary osteotomies to transversely level, advance, 
and rotate counterclockwise
•  Fat graft to ipsilateral total joint prosthesis
•  Ancillary procedures (i.e., genioplasty, rhinoplasty, turbinec-
tomies, and so on)
Surgery  stage  2  may  be  indicated  to  provide  additional  
bony and soft tissue augmentation on the ipsilateral side. This 
protocol  provides  the  most  stable  and  predictable  treatment 
outcomes.
A patient with HFM who is 6 to 12 years old with absence 
of the TMJ may benefit from a growth center transplant using 
a  sternoclavicular  graft  or  rib  graft.  Rib  grafts  are  unpredict-
able  relative  to  growth  and  stability.  Sternoclavicular  grafts 
tend  to  have  better  growth  potential,  similar  to  normal  TMJ 
growth. Orthognathic  surgery may be necessary at a  later age 
(following completion of growth) to maximize the  functional 
and esthetic results. Teenage or older patients with significant 
deformity  of  the  condyle  and  ramus  may  have  a  much  
better outcome using a patient-fitted TMJ total joint prosthesis 
1106 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
(TMJ  Concepts)  to  advance  and  lengthen  the  ramus  on  the 
ipsilateral  side.
Deferring treatment until the patient is closer to completion 
of  facial  growth  (girls,  15  years  old;  boys,  17  to  18  years  old) 
helps minimize subsequent contralateral normal growth effects 
on  the  treatment  outcome. A  mandibular  ramus  sagittal  split 
osteotomy can be performed on the contralateral side, and the 
indicated  maxillary  osteotomies  can  be  completed  as  well  as  
any  other  adjunct  procedures. Additional  reconstruction  may 
be  necessary  using  bone  grafts,  synthetic  bone,  or  alloplastic 
implants to build up the residual deformed skeletal structures. 
Soft tissue reconstruction using fat grafts, tissue flaps, and vas-
cularized free flaps, for example, may be necessary to fill out the 
soft tissue defects.
Autoimmune and Connective Tissue Diseases
Etiology. Conditions  included  in  the classification of auto-
immune and connective tissue diseases that can affect the TMJs 
are  rheumatoid  arthritis,  JIA,  psoriatic  arthritis,  ankylosing 
spondylitis,  Sjögren  syndrome,  systemic  lupus  erythematosus, 
scleroderma,  mixed  connective  tissue  disease,  and  so  on.  The 
triggers and precise pathophysiology are unknown for most of 
these  disorders.  Multiple  systems  are  usually  involved.  Joint 
damage may be mediated by cytokines, chemokines, and metal-
loproteases. Peripheral joints are usually symmetrically inflamed 
resulting  in  progressive  destruction  of  articular  structures, 
commonly accompanied with systemic symptoms.
Clinical features. Adult onset in some patients may affect the 
TMJs but not cause significant condylar resorption, particularly 
if caught early and placed on appropriate medications. However, 
when the disease onset is in the first or second decade or adult 
onset with TMJ involvement and condylar resorption, then the 
following characteristics may be present:
•  Progressive retrusion of the mandible with worsening skel-
etal and occlusal deformity
•  Indirect  involvement  of  the  maxilla  with  posterior  vertical 
hypoplasia particularlywhen occurring in growing patients
•  Class  II  occlusion  with  or  without  an  anterior  open  bite 
(Figures 74-94, A-C, and 74-95, A-C)
•  TMJ  symptoms  could  include  clicking,  crepitus,  TMJ  dys-
function  and  pain,  headaches,  myofascial  pain,  earaches,  
tinnitus, vertigo, and so on
•  Other joints and systems commonly involved
Imaging. Features may include:
•  Loss  of  condylar  vertical  dimension  and  volume;  residual 
condyle  may  become  broad  in  the  AP  direction  but  with 
significant mediolateral narrowing
•  In advanced disease, resorption of the articular eminences
•  Residual condyle may function forward beneath the remain-
ing articular eminence (Figure 74-96)
•  Decreased vertical height of the ramus and condyle
•  Skeletal  and  occlusal  Class  II  relationship;  high  occlusal 
plane  angle  facial  morphology  with  or  without  anterior  
open bite
•  Decreased oropharyngeal airway (Figure 74-97, A).
MRI imaging may show:
•  Articular  discs  may  be  in  position  but  will  usually  be  sur-
rounded by a reactive pannus that causes resorption of the 
condyles  and  articular  eminences  and  eventually  destroys  
the discs
•  AP mushrooming of the residual condyle but narrow medial-
lateral width
•  May or may not demonstrate an inflammatory response (see 
Figure 74-93)
Treatment. The  most  predictable  treatment  for  the  TMJ 
affected by autoimmune and connective tissue diseases includes:
•  Reconstruct the TMJs and advance the mandible in a coun-
terclockwise direction with patient-fitted total joint prosthe-
sis (TMJ Concepts; see Figure 74-32)72,74,135,151-155
•  Bilateral  coronoidectomy  if  the  rami  are  significantly 
advanced or vertically lengthened with the prostheses
•  Autogenous fat graft packed around the articulation area of 
the prostheses (harvested from the abdomen or buttock)75,76
•  Maxillary osteotomies if indicated
•  Any additional adjunctive procedures indicated (i.e., genio-
plasty, rhinoplasty, turbinectomies, septoplasty, and so on)
These  diseases  can  stimulate  reactive  or  heterotopic  bone 
formation around the prostheses. Therefore, it is necessary that 
fat grafts be packed around the articulating parts of the pros-
theses  to prevent  this occurrence and minimize fibrotic  tissue 
formation.75,76  Orthognathic  surgery  can  be  performed  at  the 
same time as the TMJ is reconstructed or performed at a later 
surgery, but the TMJ surgery should be performed as the first 
step in either approach.
Other techniques that have been advocated for TMJ recon-
struction  in  the  autoimmune  and  connective  tissue  diseases 
include using autogenous  tissues,  such as  temporal  fascia and 
muscle flaps,  rib grafts,  sternoclavicular grafts, vertical  sliding 
osteotomy, and so on. However, the disease process that created 
the original TMJ pathology can attack  the autogenous  tissues 
used in the TMJ reconstruction causing failure of the grafts. The 
patient-fitted  total  joint  prosthesis  with  a  fat  graft  packed 
around it is a superior technique relative to elimination of the 
disease process in the TMJ, improved function and esthetics, as 
well as elimination or decrease in pain.
When treating young growing patients (8 to 10 years old or 
older), the total joint prosthesis is still the best option to elimi-
nate  the disease process. However, because  there would be no 
growth  potential  on  the  involved  side(s)  of  the  mandible, 
orthognathic surgery will likely be necessary later, but it can be 
delayed until the patient has most of the facial growth complete. 
Then double jaw surgery can be performed, including the man-
dibular  ramus  sagittal  split  osteotomies  (preferable  to  use  an 
extraoral approach so as not to contaminate the prostheses) to 
reposition the jaws into the best alignment, or repositioning of 
the mandibular components of the prostheses, or manufactur-
ing  new  longer  mandibular  components  to  achieve  advance-
ment of the mandible in conjunction with maxillary osteotomies, 
genioplasty, and so on. These secondary procedures are highly 
predictable when performed at 14 years old or older in females 
and 16 years old or older in males. However, the vector of facial 
growth  will  change  in  younger  patients  to  a  downward  and 
backward  direction  because  the  maxillary  and  mandibular  
dentoalveolus  will  continue  to  grow  vertically  until  growth 
cessation.44,126
Our  studies  show  good  outcomes  in  treating  connective 
tissue/autoimmune  diseases  affecting  the  TMJ  with  custom-
fitted  total  joint  prostheses  (TMJ  Concepts)  for  TMJ  recon-
struction  and  mandibular  advancement,  fat  grafts,  and 
simultaneous maxillary orthognathic surgery.72,73,151-156 We have 
evaluated the efficacy of using fat grafts around the prostheses 
and  demonstrated  significant  improvement  in  function  and 
decrease in pain for patients when using the fat grafts as com-
pared to patients who did not receive fat grafts.75,76 Post-surgery 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1107
Average  follow-up  was  40.6  months.  Results  demonstrated 
minor  maxillary  horizontal  changes,  whereas  the  mandibular 
measurements remained very stable.
The 22-year-old  female pictured  in Figure 74-94, A-C pre-
sented with JIA, which was initiated when she was in her first 
decade of life, resulting in severe condylar resorption and facial 
deformity with severe mandibular retrusion. She had previous 
orthodontics as a teenager and repeated as an adult. She has a 
Class II end-on occlusion and an anterior open bite (see Figure 
74-95, A-C). She had moderate TMJ pain and headaches, severe 
snoring,  sleep  apnea,  nasal  airway  obstruction  secondary  to 
outcomes  of  115  patients  that  received  fat  grafts  around  the 
prostheses with an average post-surgery follow-up of 31 months 
demonstrated  significant  improvement  in  jaw  opening  and 
function post-surgery with no radiographic or clinical evidence 
of heterotopic bone or significant fibrosis.
Dela Coleta and colleagues evaluated 47 female patients for 
surgical  stability  following bilateral TMJ reconstruction using 
TMJ Concepts patient-fitted TMJ total joint prostheses, TMJ fat 
grafts, and counterclockwise rotation of the maxillomandibular 
complex  with  menton  advancing  an  average  of  18.4  mm  and 
the  occlusal  plane  decreasing  an  average  of  14.9  degrees.74 
FIG 74-94 This 22-year-old female has juvenile idiopathic arthritis (JIA) initiated when she was 
in her first decade of life resulting in severe condylar resorption and facial deformity with severe 
mandibular retrusion. A, Frontal view. B, Smiling. C, Profile view. The patient is seen at 42 
months post-surgery demonstrating the significant improvement using TMJ Concepts patient-
fitted total joint prostheses and maxillary osteotomies to counterclockwise rotate and advance 
the maxillomandibular complex. A genioplasty and partial nasal inferior turbinectomies were also 
conjointly performed. D, Frontal view. E, Smiling. F, Profile view. 
A B C
D E F
1108 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
apnea.  The  surgical  treatment  plan  was  determined  on  the  
prediction tracing (see Figure 74-97, B) and included:
•  Bilateral TMJ reconstruction and mandibular counterclock-
wise  rotational  advancement  with  TMJ  Concepts  patient-
fitted total joint prostheses
•  Multiple  maxillary  osteotomies  for  counterclockwise  
rotation, leveling the occlusal plane, and expansion
•  Bilateral coronoidotomies
•  Bilateral TMJ fat grafts (harvested from the abdomen);
•  Bilateral partial nasal turbinectomies
•  Genioplasty
The patient is seen 42 months after surgery, demonstrating 
significant improvement and stability in function and esthetics 
(see Figures 74-94, D-F, and 74-95, D-F). She is pain free, has 
hypertrophiedturbinates,  hypothyroidism,  and  polyarthropa-
thy.  The  three-dimensional  stereolithic  model  and  right  TMJ 
CT  scan  (see Figure 74-96, A-B) demonstrates  the  severity of 
her condylar resorption. Her previous orthodontics and man-
dibular  posturing  to  increase  her  airway  has  resulted  in  the 
condyles  postured  anterior  of  the  glenoid  fossa  in  front  of  
the  remaining  articular  eminence.  The  green  arrow  points  to 
the  fossa and red arrow points  to  the ear  canal. The articular 
eminence is completely resorbed.
The  lateral  cephalometric  analysis  (see  Figure  74-97,  A) 
demonstrates  the  severe  retrusion  of  the  mandible,  posterior 
vertical  maxillary  hypoplasia,  high  occlusal  and  mandibular 
planes, forward position of the condyles anterior to the fossae, 
and decreased oropharyngeal airway contributing to her sleep 
FIG 74-95 A to C, The pre-surgical occlusion is observed with a Class II end-on relation and an 
anterior open bite. D to F, At 42 months post-surgery, the occlusion demonstrates the functional 
improvement, Class I relation, and elimination of the open bite. 
A B C
D E F
FIG 74-96 A, This three-dimensional model demonstrates the severity of her condylar resorption. 
Her previous orthodontics and mandibular posturing to increase her airway has resulted in the 
condyles postured anterior of the glenoid fossa in front of the remaining articular eminence. The 
green arrow points to the fossa and red arrow points to the ear canal. B, Computed tomography 
(CT) scan of right temporomandibular joint (TMJ) shows the severe resorption of the condyle 
and articular eminence as well as the significant forward posturing of the condyle anterior to the 
fossa. The articular eminence is completely resorbed. 
A B
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1109
not  promote  soft  tissue  stretching,  a  solid  stability  would  be 
expected once appropriate  IRF was used. Mandibular growth, 
condylar  hyperplasia  (and  other  less  frequent  hyperplastic 
condyle pathologies), and the degree of clockwise movement of 
the  proximal  segment  are  among  the  most  frequently  men-
tioned  causes  for  mandibular  setback  instability.79-81,83,158-160 
Mandibular  setback  instability  can  also  be  affected  by  the 
decrease of the oropharyngeal airway dimensions. In such cases, 
the physiological need of airway space maintenance promotes 
forward posturing of the tongue that results in proclined lower 
incisors  and may  stimulate  remodeling of  the anterior  region 
of the mandible in a forward direction.
Condylar hyperplasia is a relatively common condition that 
can affect orthognathic surgery outcomes. Condylar hyperplasia 
is  a  generic  term  describing  conditions  that  cause  excessive 
growth  and  enlargement  of  the  mandibular  condyle.  There  
are  a  number  of  suggested  etiologies  of  condylar  hyperplasia, 
including  neoplasia,  trauma,  infection,  abnormal  condylar 
loading, and aberrant growth factors.161 These condylar pathol-
ogies can adversely affect the size and morphology of the man-
dible, alter the occlusion, and indirectly affect the maxilla with 
resultant development or worsening of dentofacial deformities, 
such as mandibular prognathism; unilateral enlargement of the 
condyle,  neck,  ramus,  and  body;  facial  asymmetry;  malocclu-
sion; pain; and post orthognathic surgery stability. Some con-
dylar  hyperplasia  pathologies  occur  more  commonly  within 
particular age ranges and genders. Identifying the specific con-
dylar hyperplasia pathology provides insight to its progression 
if untreated; the clinical, imaging, and histologic characteristics; 
as well  as  treatment protocols proven  to eliminate  the patho-
logical processes and provide stable and predictable functional 
and esthetic outcomes.
Wolford  and  colleagues  introduced  a  condylar  hyperplasia 
classification system differentiating between horizontal and ver-
tical growth vectors that are usually related to specific but dif-
ferent  mandibular  condylar  pathological  conditions.80,81  The 
two most common conditions that can adversely affect orthog-
nathic surgery stability are condylar hyperplasia types 1 and 2. 
Condylar hyperplasia type 1 results in predominately a horizon-
tal vector of mandibular growth; bilateral or unilateral creating 
mandibular prognathism, symmetric or asymmetric. Condylar 
hyperplasia  type 2  is an abnormal unilateral excessive vertical 
growth  of  the  mandible  usually  caused  by  a  condylar  osteo-
chondroma accompanied with unilateral compensatory down-
ward growth of the maxilla.
Condylar hyperplasia type 1 occurs in adolescence, and the 
pathological  process  is  usually  initiated  during  the  pubertal 
growth  phase  suggesting  a  hormonal  etiology.  Approximately 
one-third of the cases may be genetically related, but the other 
two-thirds occur  spontaneously.162 The gender distribution  in 
our study was 60% female.89 Normal jaw growth is usually 98% 
complete  in  females  at  15  years  old  and  in  males  at  17  to  18 
years old.125 Condylar hyperplasia type 1 is an accelerated and 
excessive growth of the “normal” condylar growth mechanism 
creating overgrowth of the mandible predominately in a hori-
zontal vector (mandibular prognathism) with the growth often 
continuing into the patient’s early to middle 20s, but condylar 
hyperplasia type 1 is a self-limiting growth aberration. Patients 
may  begin  with  a  Class  I  occlusal  and  skeletal  relationship  as 
they enter  their pubertal growth phase and grow  into a Class 
III  skeletal  and  occlusal  relationship  or  begin  as  a  Class  III  
and develop  into a worse Class III relationship. Condylar and 
good jaw function (incisal opening 46 mm), eats a normal diet, 
and reports elimination of snoring and sleep apnea.
Mandibular Setback
Mandibular setback instability has been reported with surpris-
ingly  frequency.157  Considering  that  mandibular  setback  does 
FIG 74-97 A, Lateral cephalometric analysis demonstrates the 
severe retrusion of the mandible, high occlusal and mandibular 
planes, forward position of the condyles anterior to the fossae, 
and decreased oropharyngeal airway. B, The prediction tracing 
illustrates the counterclockwise rotation advancement of the 
maxillomandibular complex with the TMJ Concepts patient-
fitted total joint prostheses and maxillary osteotomes, as well 
as the genioplasty to maximize the functional and esthetic 
outcomes. 
87
4
74
19
20
25
2
5
15
-2.5
40
44
A
B
S.S. STO
18
8
8 3
4
17
12
29
1110 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
tal  mandibular  growth  vector  extending  beyond  the  normal 
growth years will likely be condylar hyperplasia type 1, and the 
growth can continue into the middle 20s until cessation.
Bone scintigraphy of the TMJs in most cases will be nondi-
agnostic  in  determining  active  condylar  hyperplasia  type  1 
growth, because  the active growth center  is  extremely narrow 
and  will  not  produce  detectable  increased  activity.  Healthy 
growing  TMJs  normally  light  up  some  in  scintigraphy.  The 
growth rate of condylar hyperplasia  type 1  is not a  tumorous 
rate, as seen in condylar hyperplasia type 2, but only somewhat 
faster than the normal condylar growth rate; thus, it is usually 
difficult  to  differentiate  condylar  hyperplasia  type  1  from 
normal growth, particularly if both joints are involved. In uni-
lateral cases, it may also be difficult to determine an increased 
uptake  on  the  involved  side,  particularly  if  the  contralateral 
TMJ develops a displaced disc and associated arthritic changes 
(a common contralateral development), because this contralat-
eral TMJ may also have a  slight  increased uptake. Wrist/hand 
radiographs provide no insight to condylar hyperplasia type 1 
growth, because thereis no correlation between normal physi-
ological development and the pathological process affecting the 
mandibular condyles.
Histologically,  a  normal  condyle  is  approximately 15  to 20 
mm  long mediolaterally and 8  to 10 mm wide anteroposteri-
orly and  is composed of  the  following  tissue  layers beginning 
from  the  outside  and  progressing  inward:  fibrous  connective 
tissue  layer  forming  the  articulating  surface,  undifferentiated 
mesenchyme  proliferation  layer,  intermediate  layer,  cartilage 
layer,  compact  bone,  and  spongy  bone.163  In  condylar  hyper-
plasia  type  1,  histology  of  the  affected  condyle  commonly 
looks like a normal growing condyle without any notable path-
ological  abnormalities.  In  some  cases,  the  proliferative  layer 
may demonstrate greater thickness in some areas. The activity 
of  the  proliferative  layer  may  regulate  the  rate  at  which  the 
condyle and condylar neck (which is formed from the condyle 
by  remodeling)  will  grow.  In  normal  condyles,  the  formation 
of  cartilage  from  the  proliferative  layer  and  the  replacement 
of cartilage by bone ceases by approximately 20 years old. The 
marrow  cavity  is  entirely  occluded  from  the  remaining  carti-
lage  by  the  closure  of  the  bone  plate.164  The  inability  of  this 
plate to close in the presence of an active proliferative cartilage 
layer may be a major etiological factor in condylar hyperplasia 
type 1, and  it may correlate  to our observation  that cessation 
of  growth  related  to  condylar  hyperplasia  type  1,  which  may 
not  occur  until  the  early  to  mid-20s.44,125  Clinically,  we  have 
observed  an  increased  vertical  height  of  condyle  covered  by 
the  cartilaginous  cap  compared  to  the  normal  condyle.  Con-
ditions  that  initiate  excessive  accelerated  mandibular  growth 
after  the  pubertal  growth  phase  (15  years  old  for  females;  17 
to 18 years old  for males) are most often related  to an osteo-
chondroma  (condylar  hyperplasia  type  2)  or  other  types  of 
proliferative  condylar  pathology  (condylar  hyperplasia  type  
3 or 4).
Condylar Hyperplasia Type 1A
Clinical characteristics. Patients with bilateral active condy-
lar hyperplasia type 1A may have some or all of the following 
characteristics:
•  Development  or  progressive  worsening  of  mandibular 
prognathism
•  Worsening Class III malocclusion
•  Anterior and posterior crossbites
mandibular  growth  can  be  accelerated  bilaterally  (condylar 
hyperplasia type 1A) or unilaterally (condylar hyperplasia type 
1B)  in  a  horizontal  or  uncommonly  a  vertical  vector.  The 
increase  in  the mandibular growth rate occurs  in  the condyle 
but causes elongation of the condylar head, neck, and mandibu-
lar body, which leads to development of a Class III skeletal and 
occlusal  relation,  as  well  as  dental  compensations  where  the 
mandibular  incisors  can  become  lingually  inclined  and  the 
maxillary incisors overangulated.79,81,125 If orthognathic surgery 
is performed on patients with this condition prior to the cessa-
tion of growth (early to middle 20s), post-surgical relapse can 
be expected.
Not all prognathic mandibles are caused by condylar hyper-
plasia;  only  those  demonstrating  accelerated,  excessive  man-
dibular growth that continues beyond the normal growth years. 
Differential diagnosis includes the following:
•  Class III skeletal relationship with normal mandibular and 
maxillary growth
•  Deficient  maxillary  growth  with  a  normal  growing 
mandible
•  Condylar hyperplasia type 1 with or without deficient maxil-
lary growth
Differentiation must be clarified between condylar hyperpla-
sia type 1 and maxillary growth deficiency (maxillary hypopla-
sia). Maxillary hypoplasia can also result in a Class III occlusal 
and skeletal  relationship  in  the presence of a normal growing 
mandible  with  a  resultant  progressive  worsening  occlusion 
through the normal facial growth process (usually completed at 
15  years  old  for  females,  17  to  18  years  old  for  males)  with 
stability  of  the  jaw  and  occlusal  relationship  after  that  time. 
Maxillary  hypoplasia  creating  the  Class  III  relationship  is 
usually evident years before the pubertal growth phase. Maxil-
lary hypoplasia can also be present with accelerated mandibular 
growth (condylar hyperplasia type 1) creating a more extreme 
dentofacial  deformity.  However,  the  accelerated  mandibular 
growth  is  usually  not  evident  until  initiated  during  pubertal 
growth. Deviated mandibular prognathism is usually related to 
bilateral condylar hyperplasia type 1A where one side is growing 
faster  than  the  opposite  side  or  condylar  hyperplasia  type  1B 
where only a unilateral condyle is involved.
Analysis  of  serial  lateral  cephalometric  and  lateral  tomo-
grams  that  include  the  TMJ,  ramus,  and  mandibular  body 
should allow determination of the growth rates of the maxilla 
and mandible to differentiate the source of the Class III occlusal 
and skeletal relationship. In condylar hyperplasia type I, growth 
can  usually  be  determined  by  worsening  functional,  esthetic, 
skeletal, and occlusal changes with serial assessments (prefera-
bly  at  6  to  12  month  intervals)  consisting  of  clinical,  dental 
model, and radiographic evaluations.44,125
During  pubertal  growth,  the  normal  yearly  growth  rate  of 
the mandible measuring from condylion to point B is 1.6 mm 
for females and 2.2 mm for males.46 Growth significantly greater 
than the normal rate indicates accelerated growth likely related 
to  condylar  hyperplasia  type  1.  With  asymmetric  condylar 
growth, the amount of growth may be more difficult to deter-
mine  from  the  lateral  cephalogram  because  of  the  mandible 
shifting  toward  the  side  with  less  growth,  essentially  hiding 
some  of  the  forward  growth  and  elongation  on  the  faster 
growing side. Thus, using lateral TMJ tomograms that include 
the mandibular body, ramus, and condyle will allow superim-
position of the body, ramus, and posterior teeth to analyze the 
amount of condylar growth over time for each side. A horizon-
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1111
discs may require repositioning. If the patient is still a teenager 
or even in their early 20s, the growth process can be active and 
progressive. If there is active growth and only the orthognathic 
surgery is performed, then there will be predictable relapse with 
the mandible growing out into a Class III skeletal and occlusal 
relationship.44,125 If growth is active, then there are two predict-
able treatment options.
Option 1. Wolford’s  surgical  protocol  for  active  condylar 
hyperplasia type 1A includes:
•  High condylectomy removing 4  to 5 mm of  the top of  the 
condylar head on the involved side (both sides for bilateral 
condylar hyperplasia), including the medial and lateral pole 
areas that will arrest any further AP growth of the mandible
•  Reposition the articular discs using the Mitek anchor (Mitek 
Products Inc., Westwood, MA) technique
•  Perform  the  appropriate  orthognathic  surgical  procedures, 
including bilateral mandibular ramus osteotomies and max-
illary osteotomies if indicated
•  Additional  ancillary  procedures  as  indicated  (third  molar 
removal, genioplasty, turbinectomies, rhinoplasty, and so on)
This protocol provides predictable and stable results. These 
procedures can be done  in one operation or divided  into two 
or more operations depending on the surgeon’s skills and expe-
rience, but the TMJ surgery should be performed first.
Option 2. Delay  surgery  until  growth  is  complete;  then 
perform  orthognathic  surgery  only.  However,  because  these 
patients often continue to grow into the middle 20s, the surgery 
should  be  delayed  until  it  is  confirmed  that  the  growth  hasstopped. The longer the abnormal growth is allowed to proceed, 
the worse the facial deformity, asymmetry, and dental compen-
sations  will  become  affecting  the  dentoskeleton  along  with 
excessive soft  tissue development. This may  increase  the diffi-
culties  in obtaining an optimal  functional  and esthetic  result, 
besides the adverse effects on the occlusion, dental compensa-
tions, mastication, speech, and psychosocial development. If the 
TMJ articular discs are displaced, then TMJ surgery may still be 
indicated to reposition the discs.
Wolford’s  surgical  protocol  for  treating  active  condylar 
hyperplasia type 1A is a highly predictable treatment that will 
stop the abnormal growth and allow completion of the orthog-
nathic  surgery  at  the  same  operation  with  long-term  stable 
functional  and  esthetic  outcomes.44,125  Except  in  select  cases, 
surgical  correction  of  condylar  hyperplasia  type  1A  requiring 
double jaw surgery should be deferred until at least 14 years old 
in  females  and  16  years  old  in  males,  which  is  when  normal 
maxillary  and  mandibular  growth  are  closer  to  completion. 
Because no further AP growth of the mandible and maxilla can 
be  expected  after  high  condylectomies  and  Le  Fort  I  osteoto-
mies, residual maxillary vertical growth results in a downward 
and backward rotation of the maxillomandibular complex, but 
the occlusion should remain stable.44-46,126 If only the high con-
dylectomies  and  mandibular  osteotomies  are  performed  (no 
maxillary osteotomies), then surgery should be delayed until 15 
years old for females and 17 to 18 years old for males, because 
the maxilla can continue to grow in the AP and vertical direc-
tion,  potentially  developing  a  Class  II  occlusion  if  surgery  is 
performed  earlier  because  of  cessation  of  mandibular  growth 
from the high condylectomies.
Wolford and colleagues have demonstrated  in comparative 
studies  of  active  condylar  hyperplasia  type  1  patients  divided 
into two groups.79,81 Group 1 patients were treated with conven-
tional orthognathic surgery only and the mandible continued 
•  Dental  compensations  including  decreased  angulation  of 
lower incisors and overangulation of maxillary incisors
•  Facial shape more triangular and tapered often with weakly 
defined mandibular angles
•  Masseter muscles have less bulk than normal
•  Relatively asymptomatic for TMJ symptoms in patients with 
symmetric growth of the mandible
In asymmetric cases where one side grows faster than the other, 
patients may develop the following:
•  Facial  asymmetry  with  the  mandible  shifting  toward  the 
slower growing side
•  Anterior  and  unilateral  posterior  crossbite  on  the  slower 
growing side
•  Greater Class III occlusion on the faster growing side
•  Displaced articular disc  in  the TMJ on  the  slower growing 
side and sometimes on the faster growing side
•  TMJ  symptoms  (such  as,  clicking,  TMJ  pain,  headaches, 
masticatory dysfunction, ear symptoms, and so on) may be 
present
Imaging. Lateral  cephalometric  and  tomographic  analyses 
will demonstrate:
•  Class III skeletal and occlusal relationship, except in patients 
with  high  occlusal  plane  angulation  where  the  occlusion  
will be Class III but  the skeletal relation could be closer  to 
Class I
•  Condylar  head  and  neck  are  elongated,  but  the  top  of  the 
condyle  will  have  a  smooth,  relatively  normal  appearing 
morphology
•  In the coronal view, the top of the condyle will appear more 
rounded than normal
•  Mandibular body is elongated
•  Gonial angle may be more obtuse
•  Vertical  height  of  the  posterior  mandibular  body  may  be 
decreased
•  AP  thickness  of  the  symphysis  and  alveolus  may  be 
narrower
•  Medio-lateral width and AP dimension of the rami may be 
narrower compared to normal
•  Cranial  base  length  tends  to  be  decreased  and  the  cranial 
base angulation (Sella-Nasion to Nasion-Basion) tends to be 
increased compared to normal
•  Slope  of  the  posterior  border  of  the  ramus  compared  to 
Frankfort  horizontal  plane  may  be  angled  forward  greater 
than normal, particularly in the faster growing cases
In the MRI (see Figure 74-5, A), the articular discs are com-
monly  thin  and  may  be  difficult  to  identify.  Occasionally,  the 
articular discs can be posteriorly displaced. Posterior disc dis-
placement  only  occurs  in  these  conditions  where  there  is  an 
increased rate of vertical condylar growth that is faster than the 
rate of upward migration of the posterior ligament attachment 
of the disc, thus pulling the disc posterior to the condyle as the 
condyle continues to grow at an accelerated rate. In asymmetric 
condylar hyperplasia type 1A, disc dislocation can occur unilat-
erally (greater risk on the slower growing side) or bilaterally.
Treatment protocol. Treatment of condylar hyperplasia type 
1  depends  on  whether  the  growth  is  still  active  or  arrested. 
Because condylar hyperplasia type 1 is self-limiting relative to 
growth,  patients  in  their  middle  20s  or  older  will  not  have 
further jaw growth related to condylar hyperplasia type 1 so that 
routine  orthognathic  surgical  procedures  can  usually  be  per-
formed to correct the dentofacial deformity and malocclusion. 
However,  if  the  TMJ  discs  are  displaced  and  salvageable,  the 
1112 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
be  addressed  if  the  articular  discs  are  displaced;  a  relatively 
common occurrence  is  facial  asymmetries.  If  active growth  is 
confirmed, then there are two options for treatment.
Option 1. Wolford’s  surgical  protocol  for  active  condylar 
hyperplasia type 1B is:
1.  Unilateral high condylectomy to arrest the aberrant condylar 
growth and disc repositioning
2.  Contralateral disc repositioning if indicated
3.  Orthognathic  surgical  procedures,  often  requiring  double 
jaw surgery to optimize the functional and esthetic outcome
4.  Other ancillary procedures as indicated
This  protocol  predictably  stops  ipsilateral  mandibular 
growth  and  provides  highly  predictable  and  stable  outcomes 
with normal jaw function and good esthetics.89,165
Option 2. Delay  surgery  until  growth  is  complete,  which 
could be in the early to middle 20s; then perform orthognathic 
surgery  only.  However,  the  longer  the  abnormal  growth  is 
allowed to proceed, the worse the facial deformity, asymmetry, 
occlusion,  and dental  compensations will become, along with 
warping  of  the  mandible,  and  ipsilateral  excessive  soft  tissue 
development.  This  increases  the  difficulties  in  obtaining  an 
optimal  functional  and  esthetic  result,  besides  the  adverse 
effects  on  the  occlusion,  dental  compensations,  mastication, 
speech,  and  psychosocial  development.  If  the  TMJ  articular 
discs are displaced (a common occurrence), these patients may 
also suffer from TMJ pain, headaches, and myofascial pain. TMJ 
surgery may still be indicated to reposition the discs and stabi-
lize the joints, as well as eliminate the pain factors.
Surgery  for  condylar  hyperplasia  type  1B  cases  should  be 
deferred until 15 years old  for  females and 17  to 18 years old 
for males. The severity of the deformity, however, may warrant 
earlier surgery. If the ipsilateral high condylectomy is done too 
early (before 15 years old in females and 17 to 18 years old in 
males) where normal jaw growth is still occurring, then there is 
the  risk  of  the  unoperated  contralateral  condyle  continuing 
with normal growth and shifting the mandible toward the ipsi-
lateral  side until normal growth cessation.  In condylar hyper-
plasia type 1B, the contralateral TMJ articular disc is commonly 
displaced. Therefore, disc repositioning with the Mitek anchor 
technique would be  indicated but without  the high condylec-tomy. However, if surgery is indicated at an earlier age during 
active growth, then a high condylectomy can also be performed 
on the contralateral side so that the mandible will not grow and 
will remain symmetrical.
Condylar Hyperplasia Type 2
Condylar hyperplasia type 2 is a unilateral mandibular condylar 
enlargement  caused  by  an  osteochondroma  that  vertically 
lengthens  the  ipsilateral  mandible,  can  shift  it  toward  the 
contralateral side, and is not self-limiting relative to growth.162-
164 The growth rate for this pathology varies from slow to mod-
erate,  but  some  cases  can  have  a  more  rapid  growth  rate. 
Confirmation of the condylar pathology usually requires histo-
logical  assessment.  Osteochondromas  are  one  of  the  most 
common  benign  tumors  of  bone,  representing  approximately 
35% to 50% of all benign tumors and 8% to 15% of all primary 
bone  tumors, and  it  is  the most common tumor of  the man-
dibular condyle.
Histology. Osteochondromas (condylar hyperplasia type 2) 
include  a  cartilaginous  cap  similar  to  that  seen  in  a  normal 
growth  cartilage,  endochondral  ossification,  cartilaginous 
islands in the subcortical bone, and a marrow space contiguous 
to grow post-surgery, whereas Group 2 patients  that also had 
high condylectomies and orthognathic surgery performed had 
resultant  stable  Class  I  occlusal  and  skeletal  outcomes.  These 
studies  confirm  that  high  mandibular  condylectomies  stop 
mandibular AP growth, providing a means to achieve predict-
able and stable treatment outcomes.
Condylar Hyperplasia Type 1B
Clinical characteristics. Condylar hyperplasia type 1B is the 
unilateral form with the following common characteristics:
•  Usually grows in a horizontal direction, although there occa-
sionally can be a vertical directional component
•  The left  to right vertical  facial heights are usually relatively 
symmetric, but  the  ipsilateral  side sometimes can be verti-
cally longer
•  The mandible becomes prognathic and deviated toward the 
contralateral side
•  Increased  worsening  of  the  ipsilateral  Class  III  occlusion, 
whereas the contralateral side usually remains Class I
•  Crossbites develop anteriorly and on the contralateral side
•  The mandibular dental midline and chin shift off the facial 
midline toward the contralateral side
•  The mandible continues to grow more asymmetric beyond 
the normal growth years but usually will complete its growth 
in the early to middle 20s
•  Unilateral condylar hyperplasia may cause articular disc dis-
placement,  particularly  on  the  contralateral  side,  creating 
typical TMJ symptoms
Imaging. Radiographic  imaging  for  condylar  hyperplasia 
type 1B patients commonly shows the following features:
•  Mandibular deviated prognathism
•  Mandibular  asymmetry  primarily  in  a  transverse  direction 
(however,  there  can  occasionally  be  a  vertical  component) 
with  the  mandible  and  chin  shifted  toward  the  
contralateral side
•  Condylar head and neck on the involved side are longer in 
length as compared to the contralateral side
•  The  ipsilateral  body  of  the  mandible  may  be  more  bowed 
and the contralateral side may be more flat, creating signifi-
cant asymmetry in the axial plane of the mandible
•  Bone scans may or may not be of value in diagnosing con-
dylar hyperplasia type 1B because the growth rate, although 
accelerated,  is  still  relatively  slow  but  continuous  on  the 
involved side
In addition, if there is a displaced disc and mild arthritis on 
the contralateral side, there may not be much differentiation in 
the amount of isotope uptake comparing one side to the other. 
Serial radiographs (lateral cephalograms, cephalometric tomo-
grams, and so on), dental models, and clinical evaluations are 
usually the best diagnostic methods to determine if the growth 
process is still active.
MRI may show a displaced articular disc on the contralateral 
side  with  mild  arthritis  (see  Figure  74-5,  C)  and  sometimes 
disc displacement on the ipsilateral side of condylar hyperplasia 
type 1B. The disc on the ipsilateral side is often thinner than a 
normal disc, making it sometimes difficult to identify on MRI. 
Occasionally  there  can  be  a  posteriorly  displaced  disc  on  the 
ipsilateral side.
Treatment protocol. The  treatment  options  for  condylar 
hyperplasia type 1B are similar to those of condylar hyperplasia 
type 1A, where confirmed non-growing patients can be treated 
with traditional orthognathic surgery. The TMJs only need to 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1113
•  Loss of antegonial notching with downward bowing of the 
inferior border on the mandible
•  The inferior alveolar nerve canal may be positioned adjacent 
to  the  apices  of  the  teeth  but  more  commonly  toward  the 
inferior border of the mandible
•  Chin  vertically  longer  on  the  ipsilateral  side  and  may  be 
prominent in profile
MRI may show a displaced articular disc on the contralateral 
side  (76%  of  the  cases)  and  associated  arthritic  condylar 
changes.  The  disc  is  commonly  in  position  on  the  ipsilateral 
side, although it can also be displaced. Unless the tumor is very 
slow  growing,  bone  scintigraphy  will  usually  show  increased 
uptake particularly in the more active tumors.
Condylar  hyperplasia  type  2  can  be  subdivided  into  two 
primary groups based on tumor morphology. Condylar hyper-
plasia  type 2A  indicates an enlargement of  the condylar head 
and  neck  with  a  predominate  vertical  growth  vector  of  the 
osteochondroma without significant exophytic tumor develop-
ment. There can be unevenness or  lumpiness on  the condyle. 
Condylar hyperplasia type 2B indicates exophytic tumor exten-
sions  off  the  condyle,  usually  forward  and  medially,  with  the 
head becoming significantly enlarged and deformed. The exo-
phytic growth can also occur posterior and lateral but are less 
common.  These  tumors  usually  have  a  significant  vertical 
growth vector, but the exophytic growths, when relatively large, 
can disarticulate the condyle down and out of the fossa creating 
a  greater  exaggeration  of  the  ipsilateral  vertical  height  of  the 
jaws and face. When performing surgery to remove the tumors, 
the  incision  for  removal  of  condylar  hyperplasia  type  2A  can 
usually  be  smaller  compared  to  a  large  condylar  hyperplasia 
type  2B  that  may  require  greater  access  and  difficulty  for 
removal. Condylar hyperplasia type 2B may have a greater risk 
of  intraoperative  and  post-surgical  vascular  and  neurological 
complications.
The  different  growth  patterns  of  the  tumors  for  condylar 
hyperplasia  type 2A and 2B may be related  to  the anatomical 
origin of the tumor on the condylar head, rate of growth, and 
elongation adaptation of the muscles of mastication and other 
soft tissues on the ipsilateral side. The constraints of the rate of 
muscular and soft tissue adaptation and elongation compared 
to  the rate of  tumor growth may redirect  the  tumor develop-
ment  in  the direction of  least  resistance; anterior and antero-
medial. The roof and posterior wall of the fossa, as well as the 
lateral  and  medial  capsular  ligaments,  may  act  as  barriers, 
directing  the  growth  forward. We  have  treated  cases  with  the 
rare  development  of  the  exophytic  growth  extending  laterally 
and posteriorly.
Treatment protocol. There are two basic treatment approaches 
for managing condylar hyperplasia type 2. Because this pathol-
ogy is usually progressive and deforming, both options include 
a condylectomy to remove the tumor.
Option 1. Wolford’s  surgical  protocol  for  condylar  hyper-
plasia type 2 includes:
1.  Low  condylectomy  removing  the  ipsilateral  condyle  at  the 
condylar base, preserving the condylar neck
2.  Reshape the condylar neck to functionas the new condyle
3.  Reposition  the  articular  disc  over  the  top  of  the  condylar 
neck and stabilize
4.  Reposition the articular disc on the contralateral side when 
displaced
5.  Orthognathic surgery to correct the associated maxillary and 
mandibular deformities
with the underlying bone. It has been reported that the carti-
laginous cap may be 1 cm or greater  in  thickness  in  the axial 
skeleton.  However,  it  tends  to  be  thinner  in  the  maxillofacial 
region and may even be absent in long-standing cases. Gray and 
colleagues reported that the bony trabeculae are often thickened 
and  irregular,  resulting  in  a  consistently  large  volume  of  tra-
becular bone and a higher than normal percentage of surfaces 
covered in osteoids.166,167 They also point out the presence of an 
uninterrupted layer of undifferentiated germinating mesenchy-
mal cells, hypertrophic cartilage, and islands of chondrocytes in 
the  subchondral  trabecular  bone,  as  well  as  made  the  direct 
correlation between the scintigraphic activity and the frequency 
of cartilage islands at depth in the trabecular bone. The cartilage 
islands  are  mini  growth  centers  producing  bone,  causing 
enlargement of the condyle.
Clinical characteristics. Common clinical features of condy-
lar hyperplasia type 2 include the following:
•  Develops at any age but for most cases in the second decade 
(68% of cases)
•  Predominately occurs in females (76% of cases)
•  Increased unilateral mandibular height involving the condyle, 
neck,  ramus,  body,  and  dentoalveolous  of  the  ipsilateral 
mandible
•  Increased soft tissue volume on the ipsilateral side of the face, 
including elongation of the muscles of mastication
•  Low mandibular plane angle facial type morphology
•  Chin  asymmetry  vertically  and  transversely  with  shifting 
toward the contralateral side
•  Compensatory downward growth of the ipsilateral maxillary 
dentoalveolous
•  Lateral open bite on the ipsilateral side particularly in more 
rapid-growing pathology
•  Labial  tipping of  the mandibular  ipsilateral posterior  teeth 
and  lingual  tipping  of  the  contralateral  posterior  teeth  
may occur
•  Transverse cant in the occlusal plane
•  Mandibular anterior teeth crowns may be tipped toward the 
ipsilateral side and the long axis of the roots angled toward 
the contralateral side
•  Commonly contralateral TMJ arthritis and articular disc dis-
location (75% of cases) from the functional overload caused 
by the ipsilateral pathology accompanied by symptoms, such 
as clicking, popping, TMJ pain, headaches, and so on
Imaging. Radiographic features include the following:
•  Enlarged, elongated, deformed ipsilateral condyle (condylar 
hyperplasia type 2A), and commonly there may be exophytic 
extensions of the tumor off of the condyle (condylar hyper-
plasia type 2B)
•  Increased  AP  and  mediolateral  thickness  of  the  ipsilateral 
condylar neck
•  Increased  vertical  height  of  the  ipsilateral  mandibular 
condyle, neck, ramus, body, symphysis, and dentoalveolous 
(see Figure 74-11, A)
•  Increased  vertical  height  of  the  ipsilateral  maxillary 
dentoalveolus
•  Transverse cant in the occlusal plane
•  Facial asymmetry
•  Posterior border of the ipsilateral mandibular ramus may be 
more vertical than normal
•  Coronoid process is usually normal in size and may be dis-
placed below the zygomatic arch with elongation of the tem-
poralis muscle
1114 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
flatter.  Thus,  with  vertically  shortening  the  ipsilateral  bony 
structures and rotation of the chin toward the  ipsilateral side, 
there is excessive soft tissue bulk, including the masseter muscle 
that will make  the  ipsilateral  side appear  fuller,  even with  the 
most accurate skeletal correction.
A 15-year-old Class III female patient presented with active 
condylar  hyperplasia  type  1A,  maxillary  hypoplasia,  Class  III 
malocclusion,  and  impacted  third  molars ×  4  (Figures  74-98, 
A-E).  Pre-surgical  growth  is  demonstrated  in  Figure  74-99 
where  red  is  1  year  pre-surgery  and  white  is  immediate  pre-
surgery. The condylar growth is demonstrated in Figures 74-100 
and 74-101 where red represents 1 year pre-surgery and white 
immediate  pre-surgery.  This  excessive  growth  is  compatible 
with condylar hyperplasia type 1A. The patient was successfully 
treated with Wolford’s protocol of bilateral high condylectomies 
and  simultaneous  maxillomandibular  osteotomies,  as  well  as 
removal of the impacted third molars. Skeletal stability is dem-
onstrated  in Figure 74-102 at 9 months post-surgery with no 
significant  detectable  change  comparing  the  immediate  post-
surgery  and  9-month  follow-up  superimpositions.  Condylar 
changes and remodeling after high condylectomy is well dem-
onstrated in this clinical case with no detectable further growth 
(Figures  74-103  and  74-104).  Figure  74-105  shows  the  1-year 
post-surgery clinical results with improved function and esthet-
ics, as well as excellent  stability. Figure 74-106, A-C,  confirms 
the changes accomplished comparing the pre-surgery position 
(white)  to  the  9-month  post-surgery  position  (light  blue). 
Figure  74-107  and  Figure  74-108  show  the  condylar  changes 
from pre-surgery (white) to 9 months after surgery (light blue) 
that  includes  the  high  condylectomies  and  post-surgical 
remodeling.
Healthy and stable TMJs are necessary for quality treatment 
outcomes  in  orthognathic  surgery.  If  the  TMJs  are  not  stable 
and healthy, orthognathic surgery results may be unsatisfactory 
relative to function, esthetics, and skeletal and occlusal stability, 
as well  as pain. The oral  and maxillofacial  surgeon  should be 
suspicious of possible TMJ problems in the following types of 
patients:
•  Class II high occlusal plane angle and retruded mandibular 
morphological  type,  particularly  those  with  anterior  
open bites
•  Progressively  worsening  Class  II  occlusal  and  jaw 
relationship
•  Class III prognathism with progressive worsening
•  Facial asymmetry, particularly with progressive worsening
•  Patients  reporting  headaches,  TMJ  pain,  myofascial  pain, 
clicking and popping of the TMJs, and/or ear symptoms
The  surgeon should not  ignore  these  symptoms. With one 
or  more  of  these  symptoms,  patients  should  be  evaluated  
for  possible  TMJ  pathology.  An  MRI  of  the  TMJs  can  aide  
in  identification  of  the  specific  TMJ  pathology.  Failure  to  
recognize  and  treat  these  conditions  can  result  in  significant 
relapse, increased pain, and a greater complexity of subsequent 
treatment.
During the past two decades, major advancements have been 
made in TMJ diagnostics and the development of surgical pro-
cedures to treat and rehabilitate the pathological, dysfunctional, 
and painful TMJ. Research has clearly demonstrated that TMJ 
and  orthognathic  surgery  can  be  safely  and  predictably  per-
formed at the same operation, but it does necessitate the correct 
diagnosis  and  treatment  plan,  and  it  requires  the  surgeon  
to  have  expertise  in  both  TMJ  and  orthognathic  surgery.  
6.  Inferior border ostectomy on the ipsilateral side to reestab-
lish vertical height balance of the mandibular ramus, body, 
and symphysis if indicated
This  last procedure requires dissection and preservation of 
the  inferior alveolar nerve  if  it  is  located  low  in  the mandible 
where the ostectomy will be performed. This protocol provides 
predictable and stable outcomes, as well as optimizes the func-
tional  and  esthetic  results.  This  treatment  approach  allows 
removal of the tumor, yet still uses the enlarged condylar neck 
as the new condyle. The articular disc on the ipsilateral side and 
frequently  on  the  contralateral  side  (if  that  disc  is  displaced) 
requires  repositioningand  stabilization  to  provide  the  best 
treatment outcome relative to function, esthetics, and elimina-
tion  of  any  associated  pain  and  dysfunction.80,83  If  the  disc 
is  nonsalvageable,  then  the  authors  prefer  a  custom-fitted  
total  joint  prosthesis  to  reconstruct  the  ipsilateral  and/or  
contralateral TMJ.
Option 2. The most popular approach for treating condylar 
hyperplasia  type 2  is performing only an  ipsilateral condylec-
tomy,  either  partial  or  complete,  without  any  orthognathic 
surgery. With a partial condylectomy, usually no other surgery 
is recommended. When the condylectomy results in significant 
functional and occlusal instability, or where the entire condyle 
and neck have been removed, then condyle reconstruction tech-
niques  may  include  the  following:  TMJ  total  joint  prosthesis, 
sliding  ramus  osteotomy,  rib  graft,  sternoclavicular  graft,  free 
bone  graft,  pedicled  osseous  graft,  and  so  on. When  only  the 
ipsilateral condyle is addressed with no additional orthognathic 
surgery included, the patient is often left with a compromised 
functional  and  esthetic  result  because  the  significant  facial 
asymmetry remains, as well as a possible malocclusion. This is 
particularly the case if significant ipsilateral downgrowth of the 
maxilla  and  vertical  elongation  of  the  ipsilateral  mandibular 
body  and  ramus  has  occurred.  Some  of  these  patients  may 
require secondary orthognathic procedures  to achieve a  func-
tional occlusion and to restore good facial balance and esthetics. 
Without maintaining a functional ipsilateral articular disc when 
using the autogenous condylar reconstruction techniques, sig-
nificant post-surgical TMJ dysfunction may develop.
When  condylar  hyperplasia  type  2  is  identified  during  the 
normal growth years, then surgery should be deferred,  if pos-
sible, until 15 years old for females and 17 to 18 years old for 
males after normal jaw growth is relatively complete. The sever-
ity of the deformity, however, may warrant earlier surgery. If the 
ipsilateral low condylectomy is done too early (before 15 years 
old in females and 17 to 18 years old in males) where normal 
jaw growth is still occurring, then there is the risk of the contra-
lateral  condyle  continuing  with  normal  growth  shifting  the 
mandible toward the ipsilateral side until growth cessation. In 
condylar hyperplasia type 2, the contralateral TMJ articular disc 
is commonly displaced (76% of cases), and therefore, disc repo-
sitioning would be  indicated. However,  if  surgery  is  indicated 
at an earlier age, then a high condylectomy can be performed 
on  the contralateral  side so  that no  further growth will occur 
and  the  mandible  will  remain  symmetric.  Another  option 
would be to perform the unilateral condylectomy and plan for 
orthognathic surgery as a second stage after cessation of growth.
Ideal facial balance may be difficult to achieve after surgery 
because of the excessive amount of soft tissue development that 
occurs with the unilateral elongation and transverse asymmetry 
that  develops.  In  addition,  the  ipsilateral  mandibular  body 
becomes  more  curved  and  the  contralateral  body  contour  is 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1115
FIG 74-98 A to E, This 15-year-old female presents with bilateral condylar hyperplasia (condylar 
hyperplasia type 1A) demonstrating an accelerated and prolonged development of Class III occlu-
sion and mandibular prognathism. She was treated with bilateral mandibular high condylecto-
mies, articular disc repositioning with Mitek anchors, maxillary osteotomies, as well as bilateral 
mandibular ramus osteotomies to correct the jaw deformity. 
A
C D E
B
FIG 74-99 A to C, Cone beam computed tomography (CT) surface models with voxel-wise cranial 
base superimposition of immediate pre-surgery (white) and post-surgery (red). 
A B C
1116 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-100 Right condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel- 
wise cranial base superimposition of immediate pre-surgery 
(white) and post-surgery (red). Vector maps (bottom figures) 
show direction and amplitude of displacement/remodeling 
in mm. 
FIG 74-101 Left condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel- 
wise cranial base superimposition of immediate pre-surgery 
(white) and post-surgery (red). Vector maps (bottom figures) 
show direction and amplitude of displacement/remodeling in 
millimeters. 
FIG 74-102 A to C, Cone beam computed tomography (CT) surface models with voxel-wise 
cranial base superimposition of post-surgery (red) and 9 months follow-up (light blue) showing 
very minimal change in skeletal and dental position. 
A B C
The  surgical  procedures  can  be  separated  into  two  or  more 
surgical stages, but the TMJ surgery should be done first. With 
the correct diagnosis and treatment plan, combined TMJ and 
orthognathic  surgical  approaches  provide  complete  and  
comprehensive  management  of  patients  with  coexisting  TMJ 
pathology and dentofacial deformities.
Maxillary Stability
Studies have indicated superior repositioning of the maxilla is 
a  very  stable  procedure  whether  stabilized  with  wire  fixation  
or  bone  plates.  Most  concerns  are  in  reference  to  maxillary 
advancements and maxillary down grafting procedures relative 
to  stability.  The  state  of  the  art  today  is  in  reference  to  using 
rigid fixation for maxillary stabilization. Therefore, only papers 
where rigid fixation was employed will be included in this max-
illary stability section and studies with exclusively wire fixation 
techniques will be excluded.
Comparison Wire and Rigid Fixation
Satrom and colleagues compared wire fixation and rigid fixa-
tion  for  outcome  stability  in  35  patients  following  superior 
repositioning of the maxilla and mandibular advancement with 
sagittal split osteotomies.37 Rigid fixation was superior to wire 
fixation for maxillary (relapse 0.1 mm for rigid fixation and 0.8 
mm for wire fixation) and mandibular stability (relapse 6% for 
rigid fixation and 26% for wire fixation) resulting in less relapse.
Egbert  and  colleagues  evaluated  25  patients  and  showed 
there was better stability with rigid fixation compared to wire 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1117
FIG 74-103 Right condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of post-surgery (red) and 9 months 
follow-up (light blue). Vector maps (bottom figures) show direc-
tion and amplitude of displacement/remodeling in millimeters. 
FIG 74-104 Left condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of post-surgery (red) and 9 months 
follow-up (light blue). Vector maps (bottom figures) show direc-
tion and amplitude of displacement/remodeling in millimeters. 
FIG 74-105 A to E, The patient is seen 1 year after surgery demonstrating good facial balance 
and a good stable occlusal relationship. 
A
C D E
B
1118 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
FIG 74-106 A to C, Cone beam computed tomography (CT) surface models with voxel-wise 
cranial base superimposition of pre-surgery (white) and 9 months follow-up (light blue). 
A B C
FIG 74-107 Right condyle cone beam computed tomography 
(CT) surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of pre-surgery (white) and 9 
months follow-up (light blue). Vector maps (bottom figures) 
show direction and amplitude of displacement/remodeling in 
millimeters. 
FIG 74-108 Left condyle cone beam computed tomography(CT) surface models (front, top, and back views) with voxel-wise 
cranial base superimposition of pre-surgery (white) and 9 
months follow-up (light blue). Vector maps (bottom figures) 
show direction and amplitude of displacement/remodeling in 
millimeters. 
fixation, but the difference was not statistically different in the 
horizontal direction;  in  the vertical direction,  there was a sta-
tistically significant difference with the rigid fixation providing 
better stability.168
Maxillary Advancements
Luyk and Ward-Booth reviewed 11 patients with a mean maxil-
lary advancement of 3.7 mm.169 Seven patients had mandibular 
osteotomies,  and  the  maxillae  were  stabilized  with  four  bone 
plates and no bone grafting. They noted there was no significant 
relapse and concluded that bone grafting was not necessary for 
maxillary advancements.
Louis and colleagues looked at three different groups based 
on the amount of advancement with group 1 having a maxillary 
advancement  of  4.7  mm,  group  2,  8.2  mm,  and  group  3,  
12.3 mm.170 All were stabilized with miniplates and had man-
dibular osteotomies performed as well. There was more relapse 
as the maxillae were advanced a greater amount, but apparently 
no statistically significant difference between the groups.
Stork and colleagues presented results on 53 patients under-
going the quadrangular Le Fort I osteotomy design.171 The cases 
were bone grafted. The average maxillary advancement was 7.2 
mm  with  a  relapse  of  1.2  mm  (17%  relapse).  They  noted  no 
significant difference between cleft and non-cleft patients.
Maxillary Inferior Repositioning
Santos  and  colleageus  reported  performing  maxillary  down 
grafts  on  eight  patients  without  bone  grafting  the  maxillary 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1119
ingrowth throughout the pores of the implant and no inflam-
matory response.
Mehra and colleagues evaluated records on 74 patients who 
had Le Forte I maxillary advancements using rigid fixation and 
porous  block  hydroxyapatite  grafting.186  All  patients  also  had 
simultaneous sagittal split osteotomies. Seventeen of the patients 
were cleft palate patients and group 2 consisted of 57 non-cleft 
patients. Additionally, patients  were  subdivided as  to whether 
the maxilla was down grafted 3 mm or more. Average advance-
ment in all groups was about 5.4 mm. Relapse in the cleft group 
was  0.75  mm  and  in  the  non-cleft  group  0.47  mm.  Vertical 
relapse for those that were down grafted was less than 1 mm for 
the cleft group and 0.5 mm for the non-cleft group. This study 
demonstrated the significant stability with using porous block 
hydroxyapatite for maxillary advancement and/or down graft-
ing in cleft and non-cleft patients with good predictable stabil-
ity. This was the first study reporting stability of cleft compared 
to non-cleft patients. Advantages of porous block hydroxyapa-
tite were presented and included:
•  No donor site morbidity
•  No resorption of the graft
•  No known hypersensitivity or immune response
•  Ease of manipulation
•  No constraints on working time
•  Shorter overall surgical time compared to bone grafting
•  Shorter recovery time
•  Unlimited volume available
•  Bone and soft tissue growth into the graft
Mehra and colleagues reported on 78 patients with greater 
than 5 mm of maxillary advancement stabilized with rigid fixa-
tion  and  porous  block  hydroxyapatite  grafts.187  Three  groups 
were evaluated relative to whether concurrent superior or infe-
rior repositioning of the maxilla was performed. Twenty-seven 
patients  were  inferiorly  repositioned,  21  patients  superiorly 
repositioned, and 30 patients had straight horizontal advance-
ment. All groups showed 0.5 mm or less horizontal and vertical 
relapse.
Multiple Maxillary Osteotomies
Maxillary  osteotomies  and  three-dimensional  repositioning 
have  predictable  results  when  properly  performed.  Maxillary 
downward  repositioning  and  maxillary  widening  with  multi 
maxillary  osteotomies  are  the  two  procedures  that  require 
special attention for stable results. Our group has used 2.0 mm 
screws and 1.1 mm thickness bone plates in L shape with four 
holes (for zygomatic buttress) and in T shape with seven holes 
(for lateral nasal pillar). Two additional L shape 1.1 mm thick-
nesses with six holes can be added in cases that include signifi-
cant downward repositioning. These  long and rigid plates are 
placed at the posterior region of the zygomatic buttress and will 
improve stability. Passive adaptation of plates and precise per-
forations made at the center of each plate hole are mandatory 
for  accurate  maxillary  positioning  and  prevent  condylar  dis-
placement into the articular fossa.
Bone grafts and/or porous block hydroxyapatite are recom-
mended to fill all gaps in order to have better vertical, sagittal, 
and transverse stability, as well as enhance the healing process. 
Iliac crest harvesting is certainly an option but should be used 
only  for  unusual  cases  that  evolve  large  downward  maxillary 
movement. In most of the cases, bone grafts can be harvested 
from the proximal segment of the mandible during BSSRO (that 
should be completed prior to maxillary osteotomies).
defects with an average inferior movement of 4.7 mm.172 Post-
surgical  vertical  relapse  was  46%,  demonstrating  that  down 
grafting the maxilla without bone grafts will create a predictably 
high relapse rate.
de Mol van Otterloo and colleagues reported five cases with 
an average maxillary  inferior positioning of 3.6 mm included 
in  the  rigid  fixation  group.173  All  patients  also  had  bilateral 
mandibular  vertical  oblique  osteotomies  with  intermaxillary 
fixation  for  6  weeks,  demonstrating  reasonably  good  stability 
with a relapse of 0 to 1.0 mm. Rigid fixation was with a single 
anterior bone plate with one screw on each side of the osteot-
omy level.
Maxillary Stability in Cleft Patients
There are a number of studies evaluating the stability of Le Fort 
osteotomies in cleft  lip and palate patients.174-181 Studies had a 
mean horizontal movement of the maxilla of 3 to 8 mm. Hori-
zontal relapse at point A ranged from 20% to 40%. In the verti-
cal dimension, relapse ranged from 50% to 65% at point A. The 
increased  relapse  of  maxillary  advancement  in  cleft  patients 
may  include  the presence of  scarred palatal and  lip  tissues, as 
well  as  an  increased  difficulty  mobilizing  the  maxilla  on  cleft 
patients compared to non-cleft. In addition, patients with pos-
terior  pharyngeal  flaps  that  remain  intact  provide  additional 
difficulties.
Chua and colleagues also included use of distraction osteo-
genesis in patients with cleft lip and palate with an advancement 
of  7  mm  and  a  relapse  of  8.24%  with  a  5-year  follow-up.182 
Based on this group of studies, maxillary advancement in cleft 
patients  with  a  Le  Fort  osteotomy  can  be  expected  to  relapse 
25% to 35% after a 5 to 6 mm horizontal advancement.
Maxillary Stability with Synthetic Bone Grafts 
(Porous Block Hydroxyapatite)
The  use  of  synthetic  bone  grafts  in  orthognathic  surgery  was 
initiated in the mid-1980s.38 The use of porous block hydroxy-
apatite (Interpore International, Irvine, CA) was a major break-
through  for  applying  this  technology  (see  Figures  74-45  and 
74-46). Basic research on this material and early clinical studies 
have shown that  the use of porous block hydroxyapatite  is an 
efficacious method to bone graft the maxilla with good predict-
ability.38,39,183-185  The  initial  study  performed  on  humans  for 
orthognathic  surgery  was  initially  published  by  Holmes  and 
colleagues  in  1988,  demonstrating  good  bone  and  soft  tissue 
growth through the porous hydroxyapatite  in human subjects 
creating  a  bony  union  in  maxillary  and  mandibular  osteoto-
mies.39 Nunes andcolleagues and Ayers and colleagues evalu-
ated  long-term  bone  ingrowth  and  identified  that  the  micro 
hardness  of  porous  block  hydroxyapatite  following  bone 
ingrowth is equally as hard and strong as the normal adjacent 
bone.184,185 Wolford and colleagues introduced the use of porous 
block  hydroxyapatite  in  orthognathic  surgery  in  1987.38  The 
authors reported a high success rate in 92 consecutive patients.
Wardrop and Wolford presented records on 24 patients with 
greater  than 5 mm of advancement and 5 mm down graft of 
the maxilla using rigid fixation and porous block hydroxyapa-
tite  grafting.42 All  11  of  the  maxillary  down  graft  patients,  14 
maxillary advancement patients, and three Le Fort III midface 
advancement patients showed less than 1 mm of relapse. Biop-
sies  of  the  porous  block  hydroxyapatite  grafts  taken  on  six 
patients  in  this  study at 6 months  to 10 months after  surgery 
showed connective  tissue  ingrowth and 11.3% to 36.1% bone 
1120 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
bite  will  show  some  Class  II  malocclusion  associated  with  an 
anterior open bite tendency. The right thing to do in this situ-
ation is to remove bone plates and screws, proceed to pterygoid 
process  and  fracture,  and  appropriate  maxillary  and  condylar 
sitting, followed by new fixation (bone plates and screws). Less 
experienced  surgeons  might  instead  try  to  get  the  occlusion 
with  extensive  use  of  intermaxillary  elastics  after  surgery  and 
will face the same side-effects and instability to the maxilla that 
were described previously.
Pharmacological control of muscle activity following surgery 
is of paramount importance for maxillary stability. Right after 
surgery, muscle function may be irregular and can be excessive 
due to involuntary contraction, spasms, pain, and bruxism. Par-
ticularly in the cases of downward repositioning of the maxilla 
(at  the  anterior  and/or  posterior  region),  pharmacological 
control  of  muscle  activity  is  imperative.  We  successfully  have 
used clonazepam, 1 mg at bedtime for approximately 3 months. 
Tricyclic antidepressants could alternatively be used as muscle 
relaxants and central modulators of pain, whereas some selec-
tive  inhibitors  of  serotonin  and  noradrenalin  should  be  used 
with caution because they may increase muscle activity.
Maxillary widening with three-piece maxillary segmentation 
is one of the most versatile procedures in orthognathic surgery. 
It  allows  three-dimensional  repositioning  of  all  the  three  dis-
tinct segments in one single surgery, and it adjusts for tooth size 
discrepancies,  adjustment  of  upper  incisors  axial  inclination, 
and skeletal  leveling of bone segments in cases of accentuated 
upper  arch  curve  of  Spee  and  anterior  open  bite.  Maxillary 
widening with multi-maxillary osteotomies have been pointed 
out as the least stable procedure among all orthognathic surger-
ies.86,87,90 From previous studies, the observed rate of instability 
of Le Fort I osteotomy ranges from 11% to 60%. Phillips and 
colleagues  found  an  instability  at  the  second  molar  region  of 
49% (mean expansion of 5.4 mm), 30% at  the first premolar 
region  (mean  expansion  of  2.8  mm),  and  11%  at  the  canine 
region  (mean  expansion  of  2  mm).190  Limitations  of  this 
study  include  non-detailed  description  of  the  surgical  tech-
nique,  post-treatment  retention,  measurements  being  under-
taken  on  teeth,  and  failure  to  separate  skeletal  and  dental 
displacements.
Hoppenreijs  and  colleagues  found  instability  percentages 
ranging  from  41%  at  the  anterior  region,  46%  at  premolar 
region, and 73% at molar region after 2.2 mm, 2.9 mm, and 3.4 
mm  of  maxillary  widening  respectively.191  These  results  were 
extracted  from  samples  that  had  undergone  different  surgical 
procedures  and  different  post-surgical  protocols.  Moreover, 
dental measurements were performed on dental casts.
Marchetti  and  colleagues  observed  an  average  expansion  
of  2.75  mm  at  the  canine  region  and  3.75  mm  at  the  molar 
region.192  Instability was 0.25 mm (25%) at  the canine region 
and  0.75  mm  (20%)  at  the  molar  region.  However,  because  
of the small sample size—only 10 patients—these results may 
be questionable.
Kretschmer and colleagues observed an average instability of 
0.20 mm (9%) in the skeletal base (expansion of 2.13 mm), 1.20 
mm (60%) in the molar region (1.99 mm expansion), and 0.76 
mm  (68%)  in  the  bicuspid  region  (expansion  of  1.11  mm) 
showing dental instability, but skeletal stability.193
Regardless of the controversy found in the literature, maxil-
lary  segmentation  has  been  performed  with  significant  fre-
quency testifying for the procedure’s versatility and relevance in 
clinical practice.194
The majority of the patients requiring orthognathic surgery 
for  high  occlusal  plane  angle  facial  profile  will  benefit  from 
maxillomandibular  counterclockwise  rotation  of  the  occlusal 
plane.  This  maxillary  movement  includes  anterior  upward 
repositioning  and/or  posterior  downward  repositioning.  It  is 
very important to thoroughly mobilize the maxilla in order to 
avoid post-surgical vertical relapse at the posterior region. The 
development of posterior open bite short- or long-term follow-
ing orthognathic surgery may require reoperation to correct the 
bite. This situation can easily be avoided with trans-surgical soft 
tissue mobilization and appropriate grafting techniques.
Post-surgical  intermaxillary  elastics  should  be  used  with 
caution to avoid extrusion or intrusion of teeth and subsequent 
unwanted dental or skeletal relapse. We recommend light elas-
tics  in  the  anterior  and  posterior  teeth  during  the  minimal 
number of weeks possible for a good occlusion to be achieved 
and maintained stable. The selective use of intermaxillary elas-
tics  at  the  anterior  teeth  only  will  lead  to  posterior  open  bite 
and  serious  consequences  (mentioned  in  the  previous  para-
graph).  In  addition,  it  is  usually  important  to  have  a  palatal 
splint on the maxilla when using vertical elastics for an extended 
time  to prevent  transverse  shift of  the maxillary  teeth  toward 
the palate that creates a posterior crossbite.
Post-surgical development of a slight Class II malocclusion 
and  anterior  open  bite  can  be  controlled  with  Class  II  light 
elastics.  Patients  that  present  post-surgically  with  large  Class 
II with anterior open bite tendency cannot have their occlusion 
corrected with intermaxillary elastics. The attempt to use heavy 
elastics  and/or  for  longer  periods  will  bring  instability  to  the 
maxillary  positioning  originally  accomplished.  Dentoalveolar 
extrusion of anterior teeth and widening of the lower arch are 
the  most  common  related  side-effects  and  will  cause  increase 
of  teeth-to-upper  lip  vertical  relationship,  increase  of  inter-
labial gap, mouth breathing, and tongue interposition between 
upper and lower incisors. Lower dental arch widening second-
ary  to  excessive  use  of  Class  II  elastics  is  less  frequent,  but  it 
can aggravate the relapse tendency because a posterior crossbite 
can be created. The tongue may be positioned lower and ante-
riorly affecting the transversal stability of the maxilla. Excessive 
use  of  Class  II  intermaxillary  elastics  is  a  common  mistake 
that  frequently happens due  to  two reasons:  (1) Undiagnosed 
TMJ pathology prior to surgery will lead to post-surgical clock-
wise  rotation  of  the  mandible  secondary  to  condylar  resorp-
tion,  and  (2)  improper  condylar  seating  during  bone  plates 
fixation.188
Undiagnosed  TMJ  pathology—the  consequences  of  per-
forming  orthognathic  surgery  in  patients  with  previous  TMJ 
pathology—wereextensively  described  earlier  in  this  chapter. 
Excessive use of intermaxillary elastics to control post-surgical 
Class  II  malocclusion  will  be  ineffective  and  add  vertical  and 
transversal instability to the maxilla.
Regarding improper condylar seating, less experienced sur-
geons may face difficulties on maxillary posterior impaction or 
with large clockwise rotation of the maxillary posterior segment. 
Both of these maxillary movements will result in a posterosu-
perior  maxillary  movement  that  can  be  easily  handled  with 
pterygoid  process  fracture  (with  or  without  removal).189  Lack 
of intentionally fracture the pterygoid process can prevent the 
posterior region of the maxilla from being properly positioned 
resulting in downward condylar displacement during intermax-
illary  fixation  and  bone  plates  positioning.  Right  after  the 
removal of the intermaxillary fixation, the attempt to check the 
CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability 1121
than  20%  of  the  patients  showed  50%  or  more  instability  at  
the posterior segments relative to the surgical changes, and less 
than 10% of the sample showed more than 2 mm of absolute 
transversal  instability.  No  correlation  was  found  between  the 
amount of maxillary surgical change and post-surgical instabil-
ity  (Figure 74-110, A).  In  fact, our data  suggest  that  surgeons 
should be careful with small and large maxillary repositioning, 
because all surgical displacements seem to have similar risk of 
instability.
In conclusion, the stability of maxillary osteotomies is highly 
dependent  of  surgical  technique,  post-surgical  retention,  and 
surgeon  expertise.  Excellent  and  predictable  results  can  be 
achieved with  three-piece maxillary osteotomies  that  improve 
significantly dental, skeletal, and facial outcomes.
A recent study designed to examine and compare the skeletal 
and dental effects of surgically assisted rapid palatal expansion 
(SARPE) and multi-maxillary osteotomies using cone beam CT 
concluded that there was greater correlation between dental and 
skeletal changes in the multi-maxillary Le Fort I segmentation, 
indicating  bodily  separation  of  the  segments,  whereas  the 
SARPE  showed  noteworthy  dental  and  skeletal  tipping.195 
Dental  relapse  was  greater  than  skeletal  relapse  for  these  two 
procedures.
Our  group  retrospectively  investigated  (ongoing  unpub-
lished study) three-dimensional spatial changes of  three-piece 
maxillary osteotomy during surgery and 1-year follow-up sta-
bility with a semi-automatic mensuration algorithm.196 The aim 
of this study was to evaluate maxillary segment displacement in 
all  three planes of space rather than the transverse dimension 
only.  The  sample  was  a  set  of  tomographic  images  from  30  
high  occlusal  plane  facial  profile  patients  who  underwent  
multi-segmented orthognathic surgery. The surgical technique 
included maxillary segmentation made in a Y shape with single 
midline  osteotomy  and  two  anterior,  interdental  osteotomies 
between canines and lateral incisors. Following Le Fort I down-
fracture and prior to the  interdental midline osteotomies that 
had  been  completed,  the  patients  received  one  or  two  para-
midline  palatal  incisions  followed  by  mucosal  detachment  to 
free up all  the median  region of  the palatal mucosa  from  the 
palatal  bone.197  The  mucosal  detachment  was  performed  to 
avoid tissue stretching due to maxillary segment replacement. 
Palatal splint used was made of chemically cured acrylic resin 
that  surrounded  the  entire  palatal  surface  of  upper  canines, 
bicuspids,  and  molars  and  had  no  occlusal  contact.  It  had 
approximately 3 mm homogeneous thickness to provide trans-
verse  resistance  and  control  both  posterior  segments  inclina-
tion.  No  splint  contact  with  anterior  teeth  was  provided. 
Interproximal holes were made with a 701-fissure bur to allow 
the splint fixation on first bicuspids and first molars bilaterally 
with  circum-dental  wires  after  complete  maxillary  segment 
mobilization  and  passive  adaptation  on  the  splint  (Figure 
74-109).  Four  titanium  bone  plates  were  used  to  stabilize  all 
three  maxillary  segments  in  the  new  position.  Splint  removal 
was done 4 to 8 weeks after surgery, depending on the amount 
of segment displacement performed.
Our results showed that three-piece Le Fort I osteotomy is a 
procedure with instabilities on average smaller than 1 mm. Less 
FIG 74-109 A, Palatal splint is shown that is used to provide transverse stability for multiple-piece 
maxillary osteotomies. B, The osteotomies for the three-piece maxillary segmentation are 
observed. 
A B
• Treating clinicians must be able to provide appropriate clinical assess-
ment, indicated imaging and interpretation, dental model analysis, 
and comprehensive treatment planning and must be able to carry out 
the treatment plan accurately to completion in order to provide good 
treatment outcomes. Failure in any of these areas can result in a 
compromised or unfavorable result.
• The surgeon should have a wide base of surgical knowledge, experi-
ence, and surgical skills to provide the appropriate and required surgi-
cal treatment. Deficiencies in any of these areas can result in 
compromised or catastrophic results.
• Research has shown that the use of rigid fixation in orthognathic 
surgery, as well as appropriate bone grafting, leads to improved 
predictability and treatment outcomes. The use of wire fixation to 
stabilize bone segments results in significant relapse problems, insta-
bility, and significant compromise in treatment outcomes.
• In double jaw surgery, the selective alteration of the occlusal plane 
may improve the functional and esthetic results for patients signifi-
cantly. For example, counterclockwise rotation of the maxilloman-
dibular complex may benefit patients with sleep apnea and may be 
the primary method for correcting disorders in patients with this 
particular condition functionally and esthetically.
• The TMJs are the foundation for orthognathic surgery. Failure to 
diagnose or ignoring pre-existing TMJ dysfunction and pathosis can 
result in unfavorable orthognathic treatment outcomes, such as post-
operative pain, condylar resorption, malocclusion, jaw dysfunction, 
and facial deformity.
PITFALLS
1122 CHAPTER 74  Surgical Planning in Orthognathic Surgery and Outcome Stability
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