El espectro de la hendidura orofacial eppley2005
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El espectro de la hendidura orofacial eppley2005

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are well appreciated. Less ap-
preciated but equally common, particularly in
severe expressions of the syndrome, is the zy-
gomatico-orbital dysplasia, marked by a disrup-
tion of the zygomatic arch and inferior dis-
placement of the lateral canthus caused by
variable amounts of accompanying zygomatic
hypoplasia and resultant orbital dystopia.
Lateral facial clefts are easy to understand
embryologically, as the commissure represents
the most anterior point of mesodermal merg-
FIG. 11. Tessier no. 4 orofacial cleft.
FIG. 12. Bilateral incomplete Tessier no. 5 clefts.
ing of the maxillary and mandibular processes.
Should the fusion process remain incomplete,
a variable spectrum from furrowing of the tis-
sues to complete anatomical separation per-
sists. The pathogenesis of the lateral facial cleft
appears to be heterogeneous. A vascular cause,
attributable to embryonic hematoma forma-
tion from disruption of the stapedial artery
stem, is one proposed mechanism.77 The sever-
ity of the condition subsequently depends on
the size of the hematoma and its time course of
resolution as brachial arch development oc-
curs.78 The cause of this embryonic hemor-
rhage has been speculated to range from vas-
cular flow anomalies, such as hypertension and
hypoxia, to pharmacologic agents, such as sa-
licylates and anticonvulsants.79 Intrauterine
compression secondary to oligohydramnios in
the embryonic head region has also been sug-
gested and may account for some cases of
hemifacial microsomia that occur with other
anomalies, such as limb reduction defects.80
Clefting of the lower face (Tessier cleft no. 30)
(Fig. 1) almost universally occurs through the
midline of the lip and mandible. Although para-
median lower lip/mandibular clefting has been
reported, there are fewer than 70 reported cases
in the literature, appearing with less frequency
than the oblique facial clefts.11,81,82 Sex and racial
predilections remain indeterminate.
A range of inferior clefting has been reported
that extends from mild notching of the lower lip
and mandibular alveolus (Fig. 14) to complete
cleavage of themandible, extending into inferior
neck structures.81\u201385 Tongue involvement is typi-
cal though variable in expression, ranging from a
bifid anterior tip with ankyloglossia to the bony
cleft margins, to marked lingual hypoplasia. In-
ferior cervical defects (midline separation, hyp-
oplasia, and agenesis) of the epiglottis, strapmus-
cles, hyoid bone, thyroid cartilage, and sternum
may also be present, particularly when the cuta-
FIG. 13. Tessier no. 7 (commissure) clefts. (Above, left) Left-sided hemifacial microsomia with commissural cleft.
(Below, left) Right-sided hemifacial microsomia with commissural cleft extending to the anterior border of the
masseter. (Right) Bilateral commissural clefts without hemifacial microsomia.
neous cleft passes caudal to the gnathion point
on the chin.
The embryologic basis of median mandibu-
lar clefts lies in the failure of coaptation of the
free ends of the first visceral arches in the
midline. Once the arches are formed through
neural crest cell migration, vascularization,
and mesodermal myoblastic ingrowth, growth
centers are organized at their tips that are re-
sponsible for closing the final gap and coalesc-
ing the two sides.8 As the incisor teeth are
frequently missing along the medial mandibu-
lar margins, this suggests that partial or com-
plete failure of growth center differentiation
and development is responsible for such de-
fects rather than a simple merging and contact
maintenance. Because no animal models exist
for study of the median cleft lip, the cellular
basis for this defect may remain unknown for
some time. Presumably, however, more infe-
rior cervical defects would be caused by similar
mechanisms in the second and third visceral
arches. The occasional association of a supe-
rior midline defect (cleft palate) with a median
mandibular cleft is interesting because it sug-
gests that a broader defect in epithelial mesen-
chymal merging and fusion is occurring or that
the tongue abnormality affects palatal shelf clo-
sure in utero in these patients.86,87
This review of orofacial malformations de-
scribes clefting anomalies that emanate from
the mouth and lips\u2014the most common cleft
structure of the face. Some of these clefts are
relatively common, including the typical cleft
lip with or without cleft palate; others are ex-
tremely rare. As the causes of orofacial clefts
are better understood, it is becoming clear that
a complex interplay between genetic and envi-
ronmental variables causes these clefts. Future
study of orofacial clefts will require increas-
ingly sophisticated methods of elucidating
these subtle interactions. Orofacial clefts are of
particular relevance to plastic surgeons, who
set the world\u2019s standard for care and recon-
struction of such facial congenital deformities.
Barry L. Eppley, M.D., D.M.D.
Division of Plastic Surgery
CranioFacial Program
Indiana University School of Medicine
702 Barnhill Drive, Suite 3540
Indianapolis, Ind. 46202
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FIG. 14. Median mandibular clefts. (Above) Vermilion
notch of lower lip with central incisor diastema; (below) me-
dian cleft defect extending through the lower lip and alveolus
with ankyloglossia.
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