Phẫu Thuật Tạo Hình Grabb & Smith’s (Bản Cập Nhật – Kevin C. Chung)

C H A P T E R 2 9
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Syndromic Craniosynostosis
Wayne Ozaki and Thomas D. Willson
Key Points
The common syndromic craniosynostoses are primarily autosomal dominant and FGFR-related with
bicoronal synostosis being the most common pattern.
Phenotypic differences in the hands and feet can usefully distinguish among FGFR-related
craniosynostoses.
Early surgical interventions are aimed at reducing intracranial pressure and normalizing skull shape.
Timing of cranial vault remodeling balances the need for cranial decompression with the limited
advancement and weaker bone available in younger children.
Later surgical interventions are aimed at correcting midface hypoplasia.
Limited data are available regarding reoperation rates in syndromic craniosynostosis, but overall
complication rates are low, and there is a correlation between early vault remodeling and later
neuropsychological assessment scores.
Craniosynostosis is the abnormally early fusion of one or more ranial sutures. Although the metopic
suture normally fuses in the first year of life, the remaining major sutures typically fuse in the second or
third decade. As such, early fusion can be expected to have significant effects on not only head shape but
also the ability of the brain to grow normally. When this condition occurs without other anomalies or in
combination with anomalies that do not form a defined syndrome, it is referred to as isolated or
nonsyndromic craniosynostosis. This chapter concerns craniosynostosis in combination with defined
patterns of other anomalies: the syndromic craniosynostoses.
A review of syndromic craniosynostoses shows that there are now more than 150 described
craniosynostosis syndromes. In this chapter, we will focus our attention on the syndromes most
commonly encountered by practicing plastic surgeons: Apert, Crouzon, Saethre-Chotzen, Muenke, and
Pfeiffer syndromes. Syndromic craniosynostoses are nearly as common as isolated forms, making up 46%
of patients in one prospectively gathered database. Although a plastic surgeon in a nonpediatric practice
may never treat such a patient themselves, recognizing the signs of syndromic craniosynostosis is critical
for providing appropriate guidance and referral to the patient, their family, and other involved
practitioners.
Team-based approaches are the cornerstone of syndromic craniosynostosis treatment. Whereas in isolated
cases, cranial decompression may be the only intervention the patient requires; syndromic children often
require involvement of multiple specialists including pediatricians; geneticists; cardiologists;
pulmonologists; speech, behavioral, and occupational therapists; otolaryngologists; and plastic surgeons.
Treatment of these patients is best accomplished in either specialized practices or at tertiary children’s
facilities with experienced, dedicated craniofacial teams.
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Clinical Findings
Head shape is certainly the most striking feature of many of the craniosynostosis syndromes, but as the
term syndrome implies, it is far from the only feature these patients exhibit. Brachycephaly, a head shape
with biparietal widening and anterior-posterior restriction, results from bilateral coronal synostosis.
Turricephaly (also called oxycephaly), a steeple-shaped head with a long, high forehead resulting from
synostosis of the coronal plus another major suture, is another common head shape among these patients.
Cloverleaf-shaped head, known by its German term Kleeblattschädel, is uncommon, resulting from the
fusion of multiple major sutures, but is encountered in severe Pfeiffer syndrome patients. Other less
common head shapes in syndromic craniosynostosis include trigonocephaly, scaphocephaly, and
plagiocephaly. Trigonocephaly is typically seen with fusion of the metopic suture and leads to a
triangular forehead shape with temporal narrowing and, depending on severity, hypotelorism.
Scaphocephaly, from Greek skaphe meaning boat, results from fusion of the sagittal suture, elongating
the head in the anterior-posterior dimension and giving it a boatlike appearance. Plagiocephaly can be
seen with either prolonged positioning or preferential lying on one side of the head as well as with
unilateral fusions of the lambdoid or coronal sutures. In the synostotic cases, there is flattening on the
affected side with compensatory bossing of the head diagonally across from the fused suture.
Many of the common syndromes have similar patterns of craniosynostosis in addition to midface
hypoplasia and limb anomalies. The facial and cranial features among the syndromes are so similar in
some cases that differences in the limbs may be the main clinical differentiator between one syndrome
and another. Both simple and complex syndactylies are seen in syndromic craniosynostosis alongside
more subtle digital differences including overly broad digits and shortened digits. Anomalies of limb
length and long bone development are also described.
Advances in genetics have provided significant insight into the syndromic craniosynostoses, allowing
differentiation among phenotypically similar conditions, discussion of heritability, and explaining
connections among the various features of the syndromes. Autosomal recessive, autosomal dominant,
and X-linked inheritance patterns have all been observed among craniosynostosis syndromes. Among
those discussed in this chapter, all have autosomal dominant modes of inheritance, although in some
cases sporadic mutations are more common than familial forms. With the exception of Saethre-Chotzen
syndrome, which is associated with mutations in the TWIST1 gene, the other four syndromes are
associated with mutations in the fibroblast growth factor receptor (FGFR) family of genes.
The following subsections discuss findings of the common craniosynostosis syndromes in detail. A
summary of the information can be found in Table 29.1.
TABLE 29.1
Summary of Common Craniosynostosis Syndromes and Characteristics
Syndrome
Frequency
Common Head
Shape
Facial Features
Limb Features
Other
Associations
Intelligence
Gene
Inheritanc
Crouzon
1:60,000
Brachycephaly
Shallow orbits
Exophthalmos
Midface
hypoplasia
Anterior open
bite
Normal
extremities
Normal
FGFR2
AD
Apert
1:64,000 to
1:80,000
Brachycephaly
Turribrachycephaly
Shallow orbits
Exophthalmos
Negative
canthal tilt
Parrot beak
nose
Midface
Symmetric
syndactyly of
hands and
feet, usually
complex (2nd,
3rd, 4th
digits)
Severe acne
during
adolescence
Increased
incidence
of
disability
FGFR2
AD
possible,
mostly
sporadic
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hypoplasia
Anterior open
bite
Saethre-
Chotzen
1:25,000 to
1:50,000
Heterogenous;
brachycephaly
common
Low frontal
hairline
Eyelid ptosis
Facial
asymmetry
Overall mild
facial features
Simple
syndactyly
Brachydactyly
Clinodactyly
Radioulnar
synostosis
Short
stature
Vertebral
anomalies
Usually
normal
TWIST1
(rare
FGFR2/3)
AD,
sporadic
Muenke
1:130,000
Brachycephaly;
usually mild
Eyelid ptosis
Negative
canthal tilt
Overall mild
facial features
Thimble-like
middle
phalanges
Carpal fusion
Calcaneal-
tarsal fusion
Hearing loss
Increased
incidence
of
disability
FGFR3
(Pro250Arg)
AD,
sporadic
Pfeiffer
Type 1
(classic)
Type 2
Type 3
1:100,000
Turribrachycephaly
Kleeblattschädel
Brachycephaly or
turribrachycephaly
Exophthalmos
Hypertelorism
Strabismus
Negative
canthal tilt
Midface
hypoplasia
Shallow orbits
Severe
exophthalmos
(types 2 and 3)
All: broad
thumbs and
great toes;
partial soft
tissue
syndactyly
Types 2 and 3:
elbow
ankylosis
Survival to
adulthood
Childhood
demise
common
(types 2 and
3)
Normal
(type 1)
Profound
disability
(types 2
and 3)
FGFR1/2
AD (types
2 and 3
sporadic)
AD, autosomal dominant; FGFR, fibroblast growth factor receptor.
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Crouzon Syndrome
Craniosynostosis, usually bicoronal, associated with midface hypoplasia, shallow orbits, and
exophthalmos defines Crouzon syndrome, first described in 1912 by a French neurologist. When familial,
it is inherited in autosomal dominant fashion via mutations of the FGFR2 gene, although there is variable
expression of the characteristics, even within a single family. The prevalence of Crouzon syndrome at
birth is about 1:60,000, making it responsible for about 4.8% of cases of craniosynostosis.
As mentioned, brachycephaly is the most common calvarial deformity, although trigonocephaly and
scaphocephaly, from fusion of the metopic and sagittal sutures, respectively, have also been reported.
Other associated features include hypertelorism, parrot-beaked nose, maxillary hypoplasia, and
mandibular prognathism. Involvement of the cranial base sutures is responsible for the maxillary
hypoplasia component and when combined with normal mandibular growth results in class III
malocclusion and relative prognathism.
Exophthalmos in this syndrome can be particularly severe. Exposure keratoconjunctivitis is common;
lagophthalmos is near universal. On occasion, exophthalmos can be so severe that the globes herniate
through the eyelids. Immediate reduction is necessary to preserve vision, and tarsorrhaphy may be
indicated. Other visual changes including strabismus have also been reported.
The hands and feet are usually normal and intelligence is normal or near-normal. Figure 29.1 shows a
child with typical findings of Crouzon syndrome.
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FIGURE 29.1 A, B. Preoperative lateral and anterior views of an infant with Crouzon syndrome. C, D. Lateral and anterior
views of the same child 2 years after cranial vault remodeling and fronto-orbital advancement.
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Apert Syndrome
Apert syndrome, first described in France in 1906, shares cranial and facial features with Crouzon
syndrome. The syndrome is defined by craniosynostosis, again usually resulting in a brachycephalic or
turribrachycephalic head shape, in association with midface hypoplasia, shallow orbits, and syndactyly.
The presence of syndactyly is a distinguishing feature between Apert and Crouzon syndromes.
Although it can be inherited in an autosomal dominant fashion, there are very few reports of patients
with Apert syndrome having children. Most cases of Apert syndrome are, therefore, sporadic and result
from point mutations in exon 7 of the FGFR2 gene (amino acids 252 or 253). Estimates of the birth
prevalence of Apert syndrome vary significantly with early reports suggesting about 1:160,000, while
more recent findings suggest a rate between 1:64,000 and 1:80,000 live births.
Symmetrical hand syndactyly, the pathognomonic finding, usually affects the index, long, and ring
fingers, although the thumb and the small finger can also be involved (Figure 29.2). The syndactyly is
usually complex, involving the bone as well as soft tissue. Syndactyly of the foot similarly involves the
second, third, and fourth toes. Early referral to an experienced hand surgeon for staged syndactyly
release is essential to provide maximal function and prevent growth restriction.
FIGURE 29.2 Syndactyly of the hands of two different children with Apert syndrome. A. Mitten hand appearance, with the four
fingers fused and only the thumb free. B. Complex symmetric syndactyly, but not mitten hand.
Other associated findings in Apert syndrome largely mirror Crouzon syndrome. The nose has a parrot-
like tip with flattening of the dorsum. The eyes display characteristic exorbitism due to shallow orbits as
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well as a negative canthal vector. Maxillary hypoplasia with normal mandibular growth again results in
class III malocclusion. Severe acne, responsive to standard treatments, develops as children with Apert
syndrome reach adolescence. Children with Apert syndrome have, on average, some degree of
intellectual disability. The overall phenotype is typically more severe than in Crouzon syndrome. Figure
29.3 shows the typical facial features of a child with Apert syndrome.
FIGURE 29.3 Preoperative (A–C) and postoperative (D–F) views of an infant with Apert syndrome.
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Saethre-Chotzen Syndrome
Saethre-Chotzen syndrome was first described in 1931 and is defined by craniosynostosis in association
with facial dysmorphia and limb anomalies. Coronal synostosis is once again the most common form.
Inheritance is autosomal dominant, and unlike the other syndromes discussed in this chapter, the
majority of mutations in Saethre-Chotzen syndrome occur in the TWIST1 gene (although FGFR2 and
FGFR3 mutations have been described). Despite being autosomal dominant and highly penetrant, there is
a high degree of variability in the physical manifestations of Saethre-Chotzen. Mild phenotypes (Figure
29.4) may go undiagnosed, whereas Crouzon-like phenotypes may be misclassified without genetic
testing. The estimated birth prevalence of 1:25,000 to 1:50,000 makes this the most common of the
syndromic craniosynostoses.
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FIGURE 29.4 A, B. Preoperative anterior and lateral views of a child with Saethre-Chotzen syndrome. Despite being highly
penetrant, physical manifestations can be extremely mild, as in this case, or Crouzon-like in more severe cases. C, D. Two
years after vault remodeling.
Other facial findings in Saethre-Chotzen syndrome include facial asymmetry, hypertelorism, eyelid
ptosis, lacrimal anomalies, and a low frontal hairline. Exorbitism is not typical of the syndrome. The most
common limb anomalies are simple (cutaneous) syndactyly, brachydactyly, clinodactyly, broad great
toes, and radioulnar synostosis. Patients are typically short in stature and vertebral anomalies are also
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common. Mild to moderate intellectual disability has been reported in some cases.
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Muenke Syndrome
Muenke syndrome was described in 1996 and epitomizes the contributions molecular genetics have made
to our understanding of craniosynostosis syndromes. Sixty-one individuals from 20 unrelated families
were found to have identical point mutations (Pro250Arg) in the FGFR3 gene along with phenotypic
characteristics that define the syndrome. Inheritance is autosomal dominant, but expression is variable,
even within families. Incidence is estimated to be about 1:130,000.
Unicoronal or bicoronal craniosynostosis is by far the most common cranial manifestation, although some
carriers do not have premature suture fusion and instead have either macrocephaly or a normal head size
and shape. Facial features in Muenke syndrome patients, like Saethre-Chotzen, tend not to be strikingly
abnormal and as such the condition may be underdiagnosed and underreported; genetic testing is
advisable in cases of apparently isolated coronal synostosis. Common facial features include negative
canthal vector, eyelid ptosis, and midface hypoplasia. Sensorineural hearing loss is very common and is
usually bilateral. Developmental delay has been noted in about two-thirds of patients, although
intellectual disability is only present in about one-third.
Limb phenotypes may be suggestive of the syndrome with brachydactyly, clinodactyly, or broad thumbs
and great toes, but radiographic findings of the extremities are dispositive. Thimble-like middle phalanges
are often seen, although there is no functional significance. Other radiographic findings include calcaneal-
tarsal fusion and carpal bone fusion which, although not cardinal signs of the syndrome, are nearly
pathognomonic when present.
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Pfeiffer Syndrome
Pfeiffer syndrome was originally described in 1964 as an association among craniosynostosis, broad
thumbs and great toes with radial deviation, and partial soft tissue syndactyly of the hands and feet.
Since then, it has been subdivided into three types, of which one is autosomal dominant and the others
are sporadic mutations owing to demise prior to childbearing. The heterogeneity of Pfeiffer syndrome is
attributable to a heterogeneity of underlying mutations, which occur in either the FGFR1 or FGFR2 genes.
The syndrome is estimated to affect about 1:100,000 individuals.
Type 1 or classic Pfeiffer syndrome is as described. Intelligence is typically normal, although intellectual
disability has been reported. Other anomalies are uncommon. Type 2 Pfeiffer syndrome consists of a
Kleeblattschädel skull shape with severe exophthalmos, broad thumbs and great toes, brachydactyly, and
syndactyly. Elbow ankyloses or synostosis is found commonly in both type 2 and type 3 but rarely in type
1 Pfeiffer syndrome. Type 3 Pfeiffer syndrome has the same findings as type 2 save for the cloverleaf skull
(Figure 29.5). Multiple visceral anomalies are also common. Both type 2 and type 3 Pfeiffer syndrome
result in mortality in infancy or childhood in the vast majority of cases.
FIGURE 29.5 Pfeiffer syndrome is classified into three subtypes with type 1 representing the mildest form. A. Note the
exophthalmos, negative canthal tilt, and mild hypertelorism. B. The lateral view clearly demonstrates the turribrachycephaly
commonly found in type 1.
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Surgical Management
Goals
First and foremost, the surgical goals in syndromic craniosynostosis are functional. Reduction of
intracranial pressure (ICP), preservation of vision, and provision of functional extremities are the goals of
early interventions. Aesthetic considerations and normalization of appearance, although important, are
secondary goals and require refinement as the child grows and matures.
Intracranial hypertension results from mismatch between brain size and intracranial volume. Classic
situations involve space-occupying lesions such as blood or tumors, but craniosynostosis, which restricts
skull growth effectively, reduces the space available for the growing brain. The brain triples in size
during the first year of life and continues to grow throughout childhood. Direct recordings have
demonstrated that about one-third of children with craniosynostosis have increased ICP; another third
have borderline pressures, but such approaches are invasive. Indirect measures, such as papilledema on
fundoscopic examination are operator dependent and may not always be present. Radiographic findings
such as thumb-printing and copper-beaten appearance of the skull demonstrate increased ICP but do not
appear until later in development. Because there is an association between increased ICP and intellectual
achievement, and it is difficult to determine whether ICP is increased in any given case (and it is
impossible to say whether increased ICP will automatically lead to intellectual disability), skull
remodeling is recommended for these patients. Aesthetic improvement is a secondary benefit.
Vision represents another important surgical consideration in syndromic craniosynostoses. Bicoronal
synostosis, the most common form in the syndromes discussed, results in relatively shallow orbits; globe
size, however, is unchanged. This leads to a size mismatch between the orbits and their contents resulting
in the characteristic exophthalmic appearance of many syndromic craniosynostosis patients.
Lagophthalmos is common, and over time corneal damage can accumulate, resulting in loss of vision. In
extreme cases, the globes have been seen to herniate beyond the eyelids, becoming incarcerated and
requiring reduction to preserve vision. Ocular muscle problems including malposition and strabismus are
also common, owing to the abnormal size and shape of the orbits. Fronto-orbital advancement (FOA) as
well as the midface advancement techniques described help to deepen the orbits, providing enough room
for the globes and preserving vision. Again, there is a secondary benefit in improving upper- and midface
appearance.
Safety is of paramount importance in treating patients with syndromic craniosynostosis. These patients
will require multiple surgeries over their lifetimes, and complications can have knock-on effects not only
in terms of patient function, quality of life, and compliance outcomes but also on the need for and
difficulty of revisional procedures. None of the plastic surgery procedures patients with syndromic
craniosynostosis undergo is an emergency nor should they be done on an emergency basis. As with their
ongoing, outpatient treatment, an experienced team operating under controlled conditions is among the
most effective methods for reducing complications.
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Cranial Vault Remodeling
The first plastic surgery intervention these patients will experience is a procedure to reshape the skull.
Depending upon the sutures involved, this may take the form of FOA with anterior remodeling of the
cranial vault or, more recently, preferential posterior fossa expansion and the use of distraction
osteogenesis for both anterior and posterior cranial expansion. Suffice it to say, there are many
approaches to reshaping the skull depending on the underlying synostosis, and the traditional methods
are being supplemented, and in some cases supplanted, by new practices. For mild or moderate cranial
vault restrictions, such as in single suture synostosis, an anterior vault correction is performed at
6 months. In more severe conditions, such as the syndromic craniosynostoses, many high-volume centers
now perform posterior fossa expansion as the first intervention between 3 and 6 months of age followed
by FOA at around age 1 year and midface procedures on an as-needed basis.
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Posterior Fossa Distraction
Although the primary skull deformity in the syndromic craniosynostoses discussed thus far is
brachycephaly, distraction of the posterior fossa has emerged as a valuable addition to the surgical
armamentarium. The human brain nearly triples in size during the first year of life. This rapid growth
combined with restriction by fused calvarial sutures is responsible for the abnormal head shapes seen in
craniosynostosis patients. Timely intervention is, therefore, recommended. Early surgery, however, is
associated with higher morbidity; is more technically challenging owing to the small size and relatively
thin immature skull; and is more complicated from an anesthesia standpoint, and the volume gains from
early surgery are rapidly obliterated by the growing brain.
Distraction osteogenesis is a logical solution to some of these problems. It has been described in anterior,
mid-vault, and posterior forms. The procedure is less invasive, requiring only osteotomies in the desired
area and distractor placement (Figure 29.6). Dural dissection is minimal. This preserves growth potential
of the bone and minimizes blood loss. Distraction allows the adherent dura to expand with the overlying
bone, and the slow stretching of the overlying soft tissue permits more volume gain than is possible in a
single-stage advancement. The posterior approach also allows greater expansion than can be achieved
anteriorly.
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FIGURE 29.6 Posterior fossa distraction. A. Osteotomies are made to free the posterior calvarium, and distractors are placed
parallel to the sagittal sinus. B. Three-dimensional computed tomography demonstrating distractor placement preexpansion. C,
D. Preexpansion and postexpansion lateral cephalograms, respectively. This technique allows greater expansion than can be
achieved with anterior remodeling and fronto-orbital advancement alone.
Once the device has been placed, most reported protocols wait for a latency period of up to 5 days before
beginning distraction. Patients are distracted at home at a rate of about 1 mm per day, usually divided
half in the morning and half in the evening. Bony regenerate fills in the gaps left by the distraction. The
distraction rate is a balance: too slow a rate will result in premature consolidation, potentially requiring
additional surgery to reosteotomize the bone or breakage of the device; too fast a rate will result in low-
quality regenerate or no regenerate. Once the desired distraction has been achieved, the activation period
ends. A consolidation period of twice the activation period follows for the bony regenerate to solidify.
The distractors can then be removed on an outpatient basis.
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Fronto-Orbital Advancement
Fronto-orbital advancement (FOA) has been a mainstay of treatment for craniosynostosis for more than
40 years. Originally described by Marchac in 1978, it remains the initial treatment of choice for cranial
vault expansion in bicoronal craniosynostosis and many centers. Although there is less gain in
intracranial volume than with posterior procedures, FOA simultaneously provides anterior-posterior
expansion and attempts to reproduce the normal forehead appearance.
The frontal bone is removed, typically in one or two pieces. Depending upon the exact nature of the
deformity, the pieces can then be advanced forward and either reoriented or cut and shaped to produce
the gentle backward slope of a normal forehead. Removal of the supraorbital bar as a single piece allows
the surgeon to address the lower forehead. Externally, vertical osteotomies are made at the pterion
followed by horizontal osteotomies up to the lateral orbital rim, oblique osteotomies through the rim
itself, and a transverse osteotomy at the nasofrontal junction; the brain and globes are retracted and
protected throughout this process using malleable retractors. From an intracranial position, osteotomies
are made through the orbital roofs beginning at the pterion and progressing medially to the nasofrontal
junction, again protecting the brain and globes. The bar can then be advanced and reshaped by greenstick
fracturing. Resorbable plates and screws fix the construct in its final position. The osteotomies and final
position are depicted in Figure 29.7.
FIGURE 29.7 A. Preoperative position and osteotomies for frontal craniotomy and supraorbital bandeau for fronto-orbital
advancement. B. Postoperative position. The position can be maintained with resorbable plates, sutures, tongue-and-groove
cuts, or a combination of methods at the surgeon’s discretion.
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Midface Procedures
After cranial vault expansion, the next major procedure syndromic craniosynostosis patients undergo is
surgical reshaping of the midface. This is typically done in childhood, usually between the ages of 5 and
8 years, and is delayed as long as functional considerations will allow to permit the orbits to attain their
adult size; there is essentially no further vertical maxillary growth following midface osteotomy.
Although normalizing the facial appearance is an important outcome of midface surgery, the operations
are still functional, and functional considerations ultimately dictate timing. Severe exorbitism can
threaten vision; severe sleep apnea increases the risk of sudden death and reduces overall functioning
and achievement; severe hypertelorism can make fitting glasses difficult: these and other problems can be
addressed with the procedures described. Monobloc and Le Fort III operations move the midface in a
primarily anterior-posterior plane; facial bipartition controls horizontal and vertical orbital position as
well as midface width and can be combined with monobloc advancement. The choice of surgery depends
upon the patient’s functional needs and phenotype.
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Monobloc
The monobloc procedure moves the midface and supraorbital bar as a unit. As a result, it can be used to
correct exorbitism, midface retrusion, and forehead retrusion and offers a small increase in intracranial
volume. It is, therefore, a good option in patients for whom the forehead and midface need to be moved
the same or similar distances. Monobloc can also be combined with facial bipartition, discussed later, to
address orbital position and midface width. Both acute advancement and distraction osteogenesis are
possible, with the latter now preferred owing to a more favorable complication profile and greater
potential for advancement. The main drawback of distraction procedures is the need for two surgeries:
distractor placement and removal.
As in FOA, a frontal craniotomy allows access to the anterior cranial fossa and orbits. Orbital roof
osteotomies are made in similar fashion, continuing to and then down the lateral edge of the orbit. Next,
the body of the zygoma is osteotomized followed by the orbital floor. Pterygomaxillary osteotomies are
performed transorally. Medial orbital wall osteotomies are performed just posterior to the posterior
lacrimal crest. Finally, the orbital roofs and cranial base are osteotomized just anterior to the cribriform
plate. The segment can then be mobilized and repositioned. If acute advancement is performed, bone
grafts as well as plates and screws are used to help maintain the advancement (Figure 29.8). In the case of
distraction, we adapt the distractors to the monobloc prior to the osteotomies with one or two holes
predrilled to mark the planned position and alignment. Once the segment has been mobilized, the
distractors are reapplied. After a latency period of about 7 days, distraction proceeds at 1 mm per day.
We aim to overcorrect our patients in anticipation of further growth and inevitable relapse. The turning
arms for internal distractors can then be removed, allowing a longer consolidation period with removal of
the internal portion of the devices at about 3 months.
FIGURE 29.8 A. Preoperative position and osteotomies for monobloc advancement. The same osteotomies can be used for
both distraction and acute advancement. B. Postoperative positioning. The position is maintained with plates and screws,
tongue-and-groove cuts, or by the distractors as bony regenerate forms. Note the bone graft at the zygomatic arch.
Early experience with monobloc surgery was fraught with complications including meningitis, persistent
cerebrospinal fluid (CSF) leaks, and nasocranial fistulae alongside the more garden variety wound
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infections and relapse. Modifications to the conventional technique have significantly reduced serious
complications, from 50% to 36% in one study. The same work demonstrated a reduction of serious
complications to 0% (and overall complications from 67% to 8%) in the distraction osteogenesis group
while achieving a much larger advancement and significantly less relapse. The primary drawback of
distraction remains the need for a secondary surgery to remove the distractors.
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Le Fort III
The Le Fort III procedure moves the midface separately from the frontal bar. Under appropriate
circumstances, it can provide several advantages over the monobloc. Chief among those advantages is the
improved complication profile of separating the intracranial (FOA) component from the extracranial
component (subcranial Le Fort III). Although this obviously results in an additional surgery, a second
advantage is that it allows differential advancement of the forehead and midface, which is commonly
called for. Finally, the timing of indications for forehead and midface advancement rarely matches;
separating the surgeries allows each to be done at the appropriate time rather than compromising the
timing of one, the other, or both. Like monobloc surgery, Le Fort III can be performed either as a
distraction procedure or with acute advancement. Distraction can be done either using partially buried
internal devices or an external halo system (Figure 29.9).
FIGURE 29.9 Placement of distractors for Le Fort III distraction. Note that the footplates rest on the zygomatic arch (black
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arrow) and body of the zygoma (blue arrow). The distractor arms exit posteriorly in the temporal scalp.
We use a coronal approach with subperiosteal dissection beginning in the supraorbital area, if an
extracranial procedure is planned, and continue medially to the nasal bones, down the lateral orbital rims
and zygomatic arches, and across the infraorbital area. The orbits are also dissected in the same
subperiosteal plane. Osteotomies are made first at the zygomatic arch followed by the zygomaticofrontal
suture to enter the orbit. The osteotomy continues across the lateral orbit to the inferior fissure then
through the medial orbit taking care to remain posterior to the lacrimal apparatus. The nasal bone is cut
at the frontonasal suture below the ethmoidal arteries. Intraoral pterygomaxillary and posterior maxillary
osteotomies are performed. We begin the downfracture and then perform septal, perpendicular plate, and
vomer osteotomies. The segment can then be mobilized and repositioned. In acute advancement, a
combination of bone grafts, plates, and screws is used to stabilize the advanced segment. In the case of
distraction, we preadapt the distractors to the bony framework with pilot holes predrilled to mark
position and alignment. The distractors are reapplied and tested once the segment has been mobilized.
After a latency period of 7 days, distraction proceeds at 1 mm per day with some overcorrection to
account for growth and relapse. The distractor turning arms are removed immediately following
distraction, and buried internal devices are then removed at 3 months.
Complications of subcranial Le Fort III are less common than for monobloc advancement. A completely
extracranial approach reduces the risk of CSF leak and meningitis substantially, although not to zero. It is
important to confirm the position of structures such as the cribriform plate and the anterior extent of the
temporal lobes radiographically to avoid unplanned intracranial surgery, as these can be lower and more
anterior, respectively, in syndromic patients than might be expected. Other complications such as
anosmia and visual disturbances are uncommon. Altered sensation of the forehead, palate, and midface
occurs with some frequency. Wound healing and distractor-related complications make up the bulk of
postoperative problems. Relapse does occur, particularly with large acute advancements. In skeletally
immature patients, overcorrection of the malar eminences is critical; occlusion is addressed later, at
maturity.
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Facial Bipartition
Facial bipartition can be used alone or in combination with monobloc surgery to move the orbits and
reshape the midface (Figure 29.10). Potential exists for simultaneous correction of hypertelorism as well
as facial advancement and sagittal bending of the midface to correct the dish face deformity seen in
syndromic craniosynostoses, particularly Apert syndrome.
Coronal and upper gingival-buccal sulcus approaches are used to deglove the forehead and midface. A
bifrontal craniotomy is performed, and the bone is set aside. Typically, a triangular piece is removed from
the midline of the frontonasal bone to permit upward and medial rotation of the orbits. This also
increases the projection of the central face by increasing the curvature of the frontal bone when the two
pieces are rejoined. If the orbits are asymmetric, the osteotomies may be made asymmetric to compensate.
This and other contouring to account for movement of the supraorbital ridges are performed after the
bipartition. First, monobloc osteotomies are performed as previously described. The bony medial
intercanthal distance is measured on the table and the amount of bone to be removed is determined based
on the patient’s age, gender, and ethnicity, with an additional 5 mm overcorrection. The bone is removed
in a wedge shape corresponding to an imaginary triangle with its base at the nasofrontal junction and tip
at the midline of the maxillary alveolar ridge. The two bipartition segments are then wired together. This
closure causes separation at the palate; dissecting the midline palatal mucosa before wiring the segments
together reduces the risk of palatal tears. Pericranial flaps are used to separate the floor of the anterior
cranial fossa from the nasal cavity and are sutured in place. At this point, after the two segments have
been stabilized to each other, any planned acute advancement is performed and the construct is plated in
place, or distractors are applied.
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FIGURE 29.10 Preoperative (A) and postoperative (B) photographs of a patient undergoing monobloc and facial bipartition.
Note the change in canthal position and the reduced intercanthal distance in the postoperative photograph. C. Intraoperative
view with markings for frontal craniotomy (top is anterior). D. The triangular central midface segment has been osteotomized
and is being removed. E. Fixation of the two hemifaces after the triangular wedge has been removed and the orbits
repositioned. F. Final position of the construct with all fixation in place.
Bipartition with monobloc advancement results in differential movement of the central and lateral face,
with greater advancement centrally. Patients and physicians note significant aesthetic as well as
functional improvements in sleep apnea and corneal exposure. Bipartition results in malocclusion due to
expansion of the maxilla, which is often asymmetric. Postoperative orthodontic treatment is needed after
consolidation and in preparation for orthognathic surgery at maturity. In addition to wound and
distractor-related complications, less common problems after bipartition include persistent CSF leak,
meningitis, and visual disturbances. Relapse does occur, but can be overcome by planned overcorrection
of the intercanthal distance.
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Outcomes and Revisions
Treatment outcomes in syndromic craniosynostoses are notoriously difficult to measure. Prevention of
developmental delay is difficult to determine statistically given the relative rarity of syndromic
craniosynostoses in any center and the association between some syndromes and impaired
neuropsychosocial development. Similarly, normalization of aesthetics is by definition subjective and is
strongly influenced by the starting phenotype; patients with milder differences to start with tend to have
more aesthetically pleasing results.
McCarthy and colleagues reported a 20-year experience with syndromic craniosynostosis with
satisfactory results in 73% of patients, although reoperation was recommended in 37%. Their outcomes
are reported using Whitaker classification (Table 29.2), but the exact criteria for revision remain to be
decided on a case-by-case basis. Mulliken and colleagues reported on reoperation rates in syndromic
craniosynostoses initially treated with FOA finding high rates in Apert (100%) and Saethre-Chotzen (65%)
syndromes with much lower rate in Crouzon syndrome (5%), although they note the possibility of
selection bias among the Saethre-Chotzen group, as milder phenotypes may require no frontal surgery or
go completely undetected.
TABLE 29.2
Whitaker Classification of Craniosynostosis Surgery Outcomes
Classification
Interpretation
I
Excellent result
No refinement recommended by surgeon or patient
II
Adequate result
Minor soft tissue refinement or bony contouring; outpatient surgery
III
Poor result
Major bony revision, bone grafting, orbital repositioning; not as extensive as the original surgery
IV
Unsatisfactory result
Major craniofacial surgery recommended; essentially reproducing the extent of the original operation if not more
Adapted with permission from Whitaker, LA, Bartlett, SP, Schut, L, et al. Craniosynostosis: an analysis of the timing, treatment, and
complications in 164 consecutive patients. Plast Reconstr Surg. 1987;80(2):195-206.
Authors reporting on midface procedures uniformly note improvements in both exorbitism and sleep
apnea, although complete resolution is not seen in all patients. Distraction patients fare better in terms of
relapse than acute advancements. McCarthy and colleagues reported stable advancements after Le Fort
III distraction in both the medium and long term including some minimal additional maxillary growth.
Fat grafting is an important adjunct to the surgeries described thus far. Relatively minor postoperative
deformities or deficiencies such as mild temporal hollowing that used to require a second major cranial
vault or midface procedure can now be camouflaged by injecting fat in an outpatient setting. The
combination of minimal downtime, low morbidity, and the ability to address only the specific areas that
the patient finds bothersome has made fat grafting popular among our patients and is a standard part of
our armamentarium for treating syndromic craniosynostosis.
The treatment of syndromic craniosynostosis patient is more complex than in isolated cases. Rather than a
single procedure, these patients undergo multiple operations to reshape the cranium, to correct midface
hypoplasia, and to camouflage their differences throughout their childhood. Behavioral and social
interventions starting from an early age also play an important role in maximizing quality of life.
Although a plastic surgeon in general practice may never treat a syndromic craniosynostosis patient
themselves, understanding the common syndromes, findings, and treatment timelines can aid other
specialists in recognizing the condition and making a referral to a craniofacial team.
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Questions
1. You are asked to evaluate a 12-month-old infant with bicoronal craniosynostosis, complete
syndactylies of the hands and feet, and midface hypoplasia. Genetic testing is most likely to reveal a
mutation in
a. TWIST
b. FGFR
c. Chromodomain-helicase-DNA-binding protein 7
d. Treacle ribosome biogenesis factor 1
e. Collagen type II alpha 1 chain
2. Which of the following is an advantage of posterior fossa distraction compared with FOA for the
initial treatment of craniosynostosis?
a. More immediate correction of frontal aesthetics with posterior fossa distraction
b. Need for only one surgery in infancy with posterior fossa distraction
c. More increase in intracranial volume with posterior fossa distraction
d. Shorter operative time with FOA
e. Less need for blood transfusion with FOA
3. Which of the following is an advantage of Le Fort III compared with monobloc surgery for
correction of midface hypoplasia in syndromic craniosynostosis?
a. Monobloc allows differential correction of frontal and midface deficiencies
b. Le Fort III can be performed as a distraction procedure whereas monobloc cannot
c. Le Fort III has a favorable complication profile compared with monobloc
d. Le Fort III can be combined with facial bipartition to simultaneously correct orbital position
and facial width
e. There is no risk of meningitis or CSF leak with Le Fort III
4. A 10-year-old child who underwent surgery for craniosynostosis as an infant presents to your
office with concerns about her appearance. On examination, she is short for her age and has a low
frontal hairline as well as subtle eyelid ptosis. She has met all of her developmental milestones and is
an average student. Which is the most likely underlying craniosynostosis syndrome?
a. Muenke
b. Crouzon
c. Pfeiffer
d. Saethre-Chotzen
e. Apert
5. Which craniosynostosis syndrome is least associated with limb anomalies?
a. Apert
b. Crouzon
c. Muenke
d. Pfeiffer
e. Saethre-Chotzen
1. Answer: b. This child has the characteristics of Apert syndrome (craniosynostosis, polysyndactyly,
midface hypoplasia), one of the FGFR-associated craniosynostosis syndromes. Apert syndrome is
associated with a mutation in the FGFR2 gene, which is usually autosomal dominant. Mutations of
the TWIST gene are associated with Saethre-Chotzen syndrome. Although patients with Saethre-
Chotzen syndrome often have syndactyly of the second and third digits, involvement of the fourth
digit and complete syndactyly are less common. Anomalies in chromodomain-helicase-DNA-
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binding protein 7 are associated with CHARGE syndrome, a craniofacial syndrome that is not
typically associated with craniosynostosis. Findings in CHARGE syndrome include coloboma, heart
defects, choanal atresia, growth retardation, genital anomalies, and ear anomalies. Treacle ribosome
biogenesis factor 1 mutations are responsible for Treacher Collins syndrome. Findings include
bilateral Tessier 6, 7, and 8 clefts. There is no association with craniosynostosis, but like the FGFR-
associated craniosynostosis syndromes, it is inherited in an autosomal dominant pattern. Collagen
type II alpha 1 chain mutations are associated with Stickler syndrome. In addition to hypoplasia of
the midface and Pierre Robin sequence, Stickler syndrome is associated with hearing loss, joint
problems, and eye abnormalities.
2. Answer: c. Posterior fossa distraction offers a greater increase in intracranial volume than fronto-
orbital distraction. FOA offers the opportunity to immediately correct frontal aesthetics while
expanding the intracranial volume. Some authors do report that FOA is not always required after
posterior fossa dis-
 traction owing to spontaneous correction. Posterior fossa distraction requires
two operations in infancy: one to place the distractors and one to remove them; this is frequently
cited as a disadvantage of posterior fossa distraction. FOA is a more invasive surgery than posterior
fossa distraction with both longer operative times and higher rates of blood transfusion.
3. Answer: c. Le Fort III generally has fewer and less serious complications than monobloc surgery.
Although the risk of meningitis and CSF leak with Le Fort III is much lower than monobloc because
the procedure is intended to be extracranial, the risk is not zero. Facial bipartition can be combined
with monobloc surgery but not with Le Fort III; intracranial access and movement of the frontal
bones are necessary to accommodate the orbital movements associated with facial bipartition. As
suggested by the name, monobloc involves movement of the upper and midface as one unit, so it
does not permit differential correction of frontal and midface deficiencies. Both procedures can be
performed as either acute advancement or distraction.
4. Answer: d. Saethre-Chotzen is an autosomal dominant craniosynostosis syndrome that is
characterized by low frontal hairline, eyelid ptosis, and short stature with normal intelligence. Limb
anomalies are sometimes seen. The overall phenotype is typically mild. Crouzon syndrome is
characterized by midface hypoplasia and exorbitism with normal intelligence. Apert syndrome is
characterized by midface hypoplasia and exorbitism associated with complex syndactyly, severe
acne in adolescence, and frequently developmental delay. In Pfeiffer syndrome, findings include
midface hypoplasia, exophthalmos, and negative canthal tilt with broad thumbs and toes and simple
syndactyly; childhood mortality is common in types 2 and 3. Muenke syndrome is characterized by
ptosis, negative canthal tilt, and mild overall facial findings; thimble-like middle phalanges are
pathognomonic.
5. Answer: b. Crouzon syndrome is associated with facial and skull findings including
craniosynostosis, midface hypoplasia, and exophthalmos, but limb findings are typically absent.
Apert syndrome limb findings include complex, symmetric syndactyly of the fingers and toes. Limb
findings in Muenke syndrome include thimble-like middle phalanges on radiography as well as
carpal bone fusions. Pfeiffer syndrome limb findings include broad thumbs and toes, soft tissue
syndactyly, and, in types 2 and 3, elbow ankyloses. Saethre-Chotzen patients may have simple
syndactyly, brachydactyly, clinodactyly, and radioulnar synostosis.
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BIBLIOGRAPHY
Bradley, JP, Gabbay, TS, Taub, PJ, et al. Monobloc advancement by distraction osteogenesis decreases morbidity and relapse. Plast Reconstr
Surg. 2006;118(7):1585-1597.Bradley and colleagues describe the evolution of the monobloc procedure at a single institution. Complications are
somewhat decreased with their modified acute advancement technique but are substantially improved with distraction osteogenesis. Significantly less
relapse is also noted in the distraction osteogenesis group compared with more conventional techniques.
Cohen, MM. Perspectives on craniosynostosis. West J Med. 1980;32(6):507-513.
Cohen, MM Jr. Craniosynostosis: phenotypic/molecular correlations. Am J Med Genet. 1995;56(3):334-339.
Cohen, MM Jr. Pfeiffer syndrome update, clinical subtypes, and guidelines for differential diagnosis. Am J Med Genet. 1993;45(3):300-307.
Cohen, MM Jr, Kreiborg, S. Hands and feet in the Apert syndrome. Plast Reconstr Surg. 1995;57(1):82-96.
de Jong, T, Bannink, N, Bredero-Boelhouwer, HH, et al. Long-term functional outcome in 167 patients with syndromic craniosynostosis;
defining a syndrome-specific risk profile. J Plast Reconstr Aesthet Surg. 2010;63(10):1635-1641.
de Jong, T, Maliepaard, M, Bannink, N, et al. Health-related problems and quality of life in patients with syndromic and complex
craniosynostosis. Childs Nerv Syst. 2012;28(6):879-882.
Dederian, C, Seaward, J. Syndromic craniosynostosis. Semin Plast Surg. 2012;6(2):64-75.
Fearon, JA, Rhodes, J. Pfeiffer syndrome: a treatment evaluation. Plast Reconstr Surg. 2009;123(5):1560-1569.
Fearon, JA, Vakarakis, GM, Kolar, J. A comparative study of anterior cranial vault distraction versus remodeling. J Craniofac Surg.
2014;25(4):1159-1163.
Fernandes, MB, Maximino, LP, Perosa, GB, et al. Apert and Crouzon syndromes: cognitive development, brain anomalies, and molecular
aspects. Am J Med Genet A. 2016;170(6):1532-1537.
French, LR, Jackson, IT, Melton, LJ III. A population-based study of craniosynostosis. J Clin Epidemiol. 1990;43(1):69-73.
Gillies, H, Harrison, SH. Operative correction by osteotomy of recessed malar maxillary compound in a case of oxycephaly. Br J Plast Surg.
1950;3(2):123-127.Although modern osteotomies are placed somewhat differently, the authors describe the first subcranial Le Fort III–type procedure
for treatment of craniosynostosis-associated midface hypoplasia and malocclusion in this case report.
Goldstein, JA, Paliga, JT, Taylor, JA, Bartlett, SP. Complications in 54 frontofacial distraction procedures in patients with syndromic
craniosynostosis. J Craniofac Surg. 2015;26(1):124-128.
Goldstein, JA, Paliga, JT, Wink, JD, et al. A craniometric analysis of posterior vault distraction osteogenesis. Plast Reconstr Surg.
2013;131(6):1367-1375.
Greig, AV, Britto, JA, Abela, C, et al. Correcting the typical Apert face: combining bipartition with monobloc distraction. Plast Reconstr Surg.
2013;131(2):219e-230e.
Kruszka, P, Addissie, YA, Yarnell, CM, et al. Muenke syndrome: an international multicenter natural history study. Am J Med Genet A.
2016;170A(4):918-929.
Maliepaard, M, Mathijssen, IM, Oosterlaan, J, Okkerse, JM. Intellectual, behavioral, and emotional functioning in children with syndromic
craniosynostosis. Pediatrics. 2014;133(6):1608-1615.
Marchac, D. Radical forehead remodeling for craniostenosis. Plast Reconstr Surg. 1978;61(6):823-835.Marchac describes his technique for
remodeling of the cranial vault in the treatment of craniosynostosis. This article marks a departure from strip craniectomy, which was the standard
procedure at the time. The article also describes normal forehead anatomy and the addition of a supraorbital bar to separately correct changes in the
brow and forehead.
McCarthy, JG, Glasberg, SB, Cutting, CB, et al. Twenty-year experience with early surgery for craniosynostosis: I. isolated craniofacial
synostosis—results and unsolved problems. Plast Reconstr Surg. 1995;96(2):272-283.
McCarthy, JG, Glasberg, SB, Cutting, CB, et al. Twenty-year experience with early surgery for craniosynostosis: II. the craniofacial synostosis
syndromes and pansynostosis—results and unsolved problems. Plast Reconstr Surg. 1995;96(2):
 284-295.The authors present a treatment
algorithm for syndromic craniosynostosis patients developed over their 20-year experience. Surgical outcomes, ICP outcomes, complications, and pearls
for each syndromic group are discussed.
Morriss-Kay, GM, Wilkie, AO. Growth of the normal skull vault and its alteration in craniosynostosis: insights from human genetics and
experimental studies. J Anat. 2005;207(5):637-653.
Muenke, M, Gripp, KW, McDonald-McGinn, DM, et al. A unique point mutation in the fibroblast growth factor receptor 3 gene (FGFR3)
defines a new craniosynostosis syndrome. Am J Hum Genet. 1997;60(3):555-564.
Ortiz-Monasterio, F, del Campo, AF, Carrillo, A. Advancement of the orbits and the midface in one piece, combined with frontal
repositioning, for the correction of Crouzon’s deformities. Plast Reconstr Surg. 1978;61(4):507-516.Ortiz-Monasterio orbitofacial advancement
laid the groundwork for what would eventually become the monobloc procedure. This article discusses the original surgical technique, results, and
follow-up of a seven-patient cohort.
Patel, PA, Shetye, PR, Warren, SM, et al. Five-year follow-up of midface distraction in growing children with syndromic craniosynostosis.
Plast Reconstr Surg. 2017;140(6):794e-803e.
Paznekas, WA, Cunningham, ML, Howard, TD, et al. Genetic heterogeneity of Saethre-Chotzen syndrome, due to TWIST and FGFR
mutations. Am J Hum Genet. 1998;62(6):1370-1380.
Renier, D, Sainte-Rose, C, Marchac, D, Hirsch, JF. Intracranial pressure in craniostenosis. J Neurosurg. 1982;57(3):370-377.
Sabatino, G, Di Rocco, F, Zampino, G, et al. Muenke syndrome. Childs Nerv Syst. 2004;20(5):297-301.
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Shetye, PR, Boutros, S, Grayson, BH, McCarthy, JG. Midterm follow-up of midface distraction for syndromic craniosynostosis: a clinical and
cephalometric study. Plast Reconstr Surg. 2007;120(6):1621-1632.
Spruijt, B, Joosten, KF, Driessen, C, et al. Algorithm for the management of intracranial hypertension in children with syndromic
craniosynostosis. Plast Reconstr Surg. 2015;136(2):331-340.
Swanson, JW, Samra, F, Bauder, A, et al. An algorithm for managing syndromic craniosynostosis using posterior vault distraction
osteogenesis. Plast Reconstr Surg. 2016;137(5):829e-841e.
Taylor, JA, Bartlett, SP. What’s new in syndromic craniosynostosis surgery? Plast Reconstr Surg. 2017;140(1):82e-93e.
Tessier, P. Relationship of craniostenosis to craniofacial dysostoses, and to faciostenoses: a study with therapeutic implications. Plast Reconstr
Surg. 1971;48(3):224-237.
Tessier, P. The definitive plastic surgical treatment of the severe facial deformities of craniofacial dysostosis, Crouzon’s and Apert’s diseases.
Plast Reconstr Surg. 1971;48(5):419-442.Tessier describes his early techniques for treating the facial deformities associated with Crouzon and Apert
syndromes. Morphologic and functional considerations for each syndrome are described in detail in addition to step-by-step approach to subcranial Le
Fort III. Complications and subsequent complementary surgeries are also discussed.
Tiwana, PS, Turvey, TA. Subcranial procedures in craniofacial surgery: the Le Fort III osteotomy. Oral Maxillofac Surg Clin North Am.
2004;16(4):493-501.
Tolarova, MM, Harris, JA, Ordway, DE, Vargervik, K. Birth prevalence, mutation rate, sex ratio, parents’ age, and ethnicity in Apert
syndrome. Am J Med Genet. 1997;72(4):394-398.
Utria, AF, Mundinger, GS, Bellamy, JL, et al. The importance of timing in optimizing cranial vault remodeling in syndromic craniosynostosis.
Plast Reconstr Surg. 2015;135(4):1077-1084.
Van der Meulen, JC. Medial fasciotomy. Br J Plast Surg. 1979;32(4):339-342.Van der Meulen medial faciotomy is an early approach to the facial
bipartition for simultaneous correction of hypertelorism and maxillary malposition.
Vogels, A, Fryns, JP. Pfeiffer syndrome. Orphanet J Rare Dis. 2006;1:19.
Whitaker, LA, Bartlett, SP, Schut, L, Bruce, D. Craniosynostosis: an analysis of the timing, treatment, and complications in 164 consecutive
patients. Plast Reconstr Surg. 1987;80(2):195-212.
Whitaker, LA, Munro, IR, Salyer, KE, et al. Combined report of problems and complications in 793 craniofacial operations. Plast Reconstr
Surg. 1979;64(2):198-203.
Wilkie, AO, Byren, JC, Hurst, JA, et al. Prevalence and complications of single-gene and chromosomal disorders in craniosynostosis.
Pediatrics. 2010;126(2):e391-e400.
Wong, GB, Kakulis, EG, Mulliken, JB. Analysis of fronto-orbital advancement for Apert, Crouzon, Pfeiffer, and Saethre-Chotzen syndromes.
Plast Reconstr Surg. 2000;105(7):2314-2323.
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C H A P T E R 3 0
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Craniofacial Microsomia and Principles of
Craniofacial Distraction
Sergey Y. Turin and Arun K. Gosain
Key Points
Craniofacial microsomia
This is the second most common congenital craniofacial anomaly after cleft lip or palate.
Abnormality of structures arises from the first and second branchial arches, with multiple tissue
types affected (skeletal structures, ear, nerve, and muscle).
May be bilateral or unilateral—thus craniofacial is the preferred term.
Comprehensive treatment of the patient’s unique constellation of symptoms is the cornerstone
of management.
Controversy is in timing of surgery and osteotomies required—early distraction of mandible and
orthodontic control of growing maxilla (as per McCarthy’s group) versus waiting for skeletal
maturity to perform orthognathic surgery for correction of both jaws (Obwegeser method).
Craniofacial distraction
Only process to create new bone and avoid grafts/flaps; bone formation takes places without
cartilaginous intermediate.
This is the only process to also provide gradual expansion of soft-tissue envelope.
There are three phases—latency (4–5 days), distraction (4–6 weeks, or until desired amount of
advancement is obtained), and consolidation (6–8 weeks).
Distraction rate standard is 1 mm per day, but may be higher if mandibular distraction is done
in infancy.
Early distraction of midface (Le Fort I or III osteotomies) can be considered if maxillary and
malar asymmetry is significant before skeletal maturity.
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Craniofacial Microsomia
Craniofacial microsomia (CFM) is one of a large set of craniofacial disorders characterized by failure or
inadequacy of facial skeleton and soft-tissue development. Although initially termed hemifacial
microsomia, the term craniofacial microsomia is more accurate as a number of patients present with bilateral
findings, as well as findings beyond the face per se (i.e., the ear). This same entity has also been
previously referred to as first and second branchial arch syndrome, otomandibular dysostosis, lateral
facial dysplasia, and oculoauriculovertebral (OAV) sequence or equivalent. In 1963, Gorlin 1 proposed the
term oculoauriculovertebral dysplasia spectrum to represent a more inclusive set of disorders. The OAV
spectrum includes a variable phenotype and affects a greater range of structures, including the skeletal
and soft-tissue components of the face, orbits, and cranium, as well as the axial skeleton and visceral
structures.
It is likely more accurate to consider CFM as a subset of OAV dysplasia, with a presentation limited to
disorders of tissues stemming from the first and second branchial arches, most commonly thought of as
involving the ear and the mandible. In turn, Goldenhar syndrome may be considered as a subset of both
OAV spectrum and CFM, defined by ocular anomalies (most commonly epibulbar dermoids or
lipodermoids), auricular anomalies (ranging from microtia to accessory tragal remnants), and vertebral
anomalies.
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Epidemiology
CFM is regarded as the second most common craniofacial anomaly after cleft lip/palate. Grabb’s seminal
1965 article on the topic estimated the prevalence to be approximately 1 in 5600 based on the local
hospitals’ data, 1 but incidence as frequent as 1 in 3000 has been cited. 2 Owing to the variable
presentation and relatively low incidence, it is difficult to obtain a more accurate estimate of the true
incidence of CFM.
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Pathophysiology
The exact pathogenesis of CFM is yet to be determined, but two hypotheses are currently dominant:
tissue insult due to hemorrhage/ischemia caused by stapedial artery malformation, or disruption of
neural crest cell migration. Thalidomide, retinoic acid, and maternal diabetes have also been linked to this
disorder, 3 but the exact mechanism of their effect is also still under investigation.
The vascular insult hypothesis describes a defect in the stapedial artery, which is a temporary hyoid
artery collateral, causing a hematoma or hemorrhage. This hemorrhage, in turn, compromises the
developing first and second branchial arches. A variation of this hypothesis was first advanced by
Braithwaite in 1949, supposing a deficiency of the stapedial artery in irrigating the affected tissues in the
period prior to formation of the external carotid artery. This hypothesis was further supported
experimentally by Poswillo, who showed that triazene and thalidomide led to development of a focal
area of hemorrhage and disruption of the forming stapedial artery in the developing faces of mice and
monkeys. The animals then went on to exhibit the microtia and mandible hypoplasia consistent with a
CFM phenotype. 4 However, later reexamination of these experiments cast doubt on the vascular insult
hypothesis because of the timing of hemorrhage inconsistent with drug administration and lack of
explanation for associated anomalies present in OAV dysplasia, such as renal or vertebral defects. 5
More recently, Johnston and Bronsky proposed that a disruption in neural crest cell migration may be
responsible for the findings seen in OAV dysplasia and CFM. 6 The widely varied roles of neural crest
cells in the development of the craniofacial skeleton and soft tissues provide a possible explanation for
the rather heterogeneous OAV dysplasia phenotypes due to different populations of neural crest cells
affected. There are also data correlating retinoic acid and diabetes (i.e., hyperglycemia) with neural crest
cell apoptosis in embryogenesis, lending further credence to this hypothesis. 7
It has been believed traditionally that most cases are sporadic: a relatively large cohort study in 1983
showed 45% of patients with OAV dysplasia/Goldenhar syndrome/CFM had some family history of
similar findings, but only 6% to 8% of first-degree relatives were affected. 8 Since then, a number of
chromosomal anomalies have been loosely tied to CFM 9 and the related disorders falling under the OAV
dysplasia umbrella, including trisomies of chromosomes 7, 9, 18, and 22, among a number of other
rearrangements and deletions. Some recent studies suggest that CFM may, in fact, exhibit an autosomal
dominant pattern of inheritance with variable penetrance. 10 Nevertheless, identification of a responsible
genetic locus remains elusive, supporting multifactorial inheritance.
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Presentation
Interestingly, CFM more commonly tends to affect the right side (∼60%) and is more frequent in males
(up to 65% males). 11 The true rate for bilateral versus unilateral presentation is difficult to determine
often because of unclear diagnostic criteria used (e.g., including a preauricular tag or not as an affected
hemiface), but the literature supports a rate of bilateral presentation ranging from as low as 5% to over
30% of cases. 12
CFM can affect many structures with variable degrees of severity, producing a wide spectrum of clinical
presentations (Figures 30.1 and 30.2). The mandible, soft tissue, facial skeleton, facial muscles, ears, and
related nervous system structures can all be affected. The frequency of involvement of any particular
structure has not been definitively determined, and the current best data as noted in the following
sections are compiled from existing case series. 9,13–15
FIGURE 30.1 This patient first presented for facial asymmetry evaluation at 7 years of age. A. The typical asymmetry of the
mandible, chin, and ear position is typical of the natural progression of a patient with CFM. B. Note also the decreased cheek
projection and midface volume on the affected left side as seen in the basilar view.
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FIGURE 30.2 This 7-month-old infant with Goldenhar syndrome was found to exhibit a complex accessory tragus and cervical
spine vertebral anomalies, but not the commonly found epibulbar dermoids. His macrostomia (Tessier cleft #7) is also a
common secondary finding in CFM.
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Mandible
Mandibular hypoplasia is usually the most obvious finding, as well as the most common, present in over
90% of patients. The ramus and condyle are usually affected much more than the body or ipsilateral
parasymphysis, with some authors maintaining that the condyle is affected to some degree in every
patient with CFM. The degree of hypoplasia can vary from a mandible that is morphologically normal
but overall small in size to a mandible with absent condyle, ramus, and angle. With progressing degrees
of severity, the body of the mandible becomes short and hypoplastic, curving superiorly in the direction
of the malformed temporomandibular joint (TMJ). The degree of condyle and ramus malformation
corresponds to changes in the glenoid fossa. The glenoid fossa loses concavity and flattens and can be
malformed frankly in approximately 27% of patients. The pivot point for the hypoplastic ramus or condyle
is translated anteriorly when compared with the contralateral TMJ. The double joint function of a normal
TMJ may be lost, resulting in a simple hinge joint, limiting mandible depression and mouth opening. In
unilateral cases, the chin will deviate to the affected side, and there will be corresponding loss of facial
contour over the hypoplastic angle. Loss of mandibular height at the angle will produce loss of facial
height posteriorly and creates an occlusal cant. Up to 27% of patients also present with hypodontia,
which correlates in severity to the degree of mandibular hypoplasia.
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Maxilla and Zygoma
Both of these arise from maxillary process of the first branchial arch and are frequently hypoplastic as
well. The maxilla and zygoma may be deficient in the axial, sagittal, or coronal planes, with some severe
cases showing an absence of the zygomatic arch. These changes correlate to the less projecting, flattened
cheek and deficient lateral facial contour seen in these patients. Moreover, the smaller maxilla is
associated with a superior displacement of the maxillary sinus and nasal base, in line with the general
elevation of the occlusal plane on the affected side.
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Cranial Base and Other Skeletal Involvement
Skeletal changes in CFM extend beyond the facial skeleton and glenoid fossa, involving the temporal and
sometimes frontal bones, where flattening akin to plagiocephaly may be seen in up to 12% of patients.
The cranial base itself may be affected as well, as shown in recent imaging-based studies noting
asymmetry of cranial base landmarks in CFM patients. 16,17
Importantly, the most common site of extracranial bony involvement is the axial skeleton, with vertebral
or rib anomalies in 8% to 79% of patients. The manifestations of vertebral anomalies are varied and
include hemivertebrae, block vertebrae, scoliosis/kyphoscoliosis, and spina bifida.
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Nervous System, Eye, and Orbit
The nervous system may be involved in CFM in 2% to 69% of patients, as manifested by abnormalities of
the cranial nerves and the eye as an extension of the central nervous system. Facial nerve paresis and
palsies have been reported, as well as involvement of the vestibulocochlear nerve (CN VIII), but any
cranial nerve may be involved. Eye anomalies may range from microphthalmia, vertical dystopia,
impairment of extraocular movements to frank anophthalmia. 3 Epibulbar dermoids are more frequently
associated with Goldenhar syndrome but may also be seen in CFM.
The central nervous system defects commonly include neural tube defects, corpus callosum agenesis or
hypoplasia, intracranial lipoma, Arnold-Chiari malformations, hydrocephaly, ventriculomegaly, and
cerebral hypoplasia. Developmental disorders including intellectual disability, language or speech
developmental delay, and neuropsychomotor delay have been seen in 8% to 73% of patients. The
presence of brain anomalies is well correlated with ocular findings, and epibulbar dermoids specifically.
18
The cranial nerve most commonly involved is the facial nerve (CN VII), which can be due to hypoplasia
or agenesis of the nerve trunk peripherally or of the facial nerve nucleus in the brainstem, so facial
animation should be thoroughly documented for these patients.
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Skin and Soft Tissue
Aside from the auricular appendage, macrostomia, muscles of mastication, and salivary glands are
probably the soft-tissue structures that are significantly involved.
Macrostomia can be seen in up to 35% of patients, with wide variations in severity. This can be
manifested as lateral displacement of the oral commissure due to hypoplasia of the mandible and cheek
soft tissues or as a frank full-thickness defect, essentially constituting a facial cleft. Clefting of the lip and
palate has also been reported and has been raised as an argument against the hematoma pathogenesis
hypothesis because it would be less likely that an insult primarily affecting the mandible and lateral face
would also be responsible for fusion of the palatal shelves or maxillary prominences anteriorly.
Hypoplasia of the muscle tissues is seen in muscles derived from the first and second branchial arches,
thereby encompassing the muscles of mastication as well as the muscles of facial expression. The
weakness and loss of bulk exacerbate the facial contour changes on the affected side as well as animation
asymmetry. The severity of muscle hypoplasia appears to be correlated to the overall severity of the
disorder. 19 Interestingly, one study of patients with Pruzansky grade I and II mandibular hypoplasia
found this relationship to hold in regard to the masseter, but not the temporalis muscle, perhaps
suggesting a differential effect on these two structures, although more data would be needed from more
severe cases before drawing a conclusion. 20
Salivary gland involvement tends to be predominantly confined to hypoplasia or agenesis of the parotid
duct or the gland itself.
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Systemic
Less commonly, systemic anomalies are encountered as well. There are cardiovascular findings in up to
33% of patients, including tetralogy of Fallot, ventricular septal defects, transposition of the great vessels,
and aortic arch anomalies. Genitourinary defects are seen in up to 18% of patients, including absent
kidney, double ureter, crossed renal ectopia, hydronephrosis, and hydroureter. More rarely, pulmonary
and gastrointestinal anomalies may be encountered in up to 15% and 12% of patients, respectively.
Notably, the presence of a single extracraniofacial anomaly is associated with an increased chance of
others being present, so any findings in one of the cardiac/renal/vertebral systems should prompt a
thorough workup of the rest. 11,15
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Ears
Malformation or hypoplasia of the auricular structures is a sine qua non for CFM, with all patients
presenting with some abnormality. This may be a mild manifestation, such as a preauricular tag, which is
usually an accessory cartilaginous appendage representing an accessory tragus or tragal remnants and
not simple skin tags or acrochordons, for which these may be commonly confused. More severe
presentations include all degrees of microtia, anotia, and aural atresia. There is some thought that an
isolated accessory tragal remnant may be the only clinical manifestation in a number of patients with
milder forms of OAV dysplasia or CFM. Without other, more severe, anomalies, these patients may avoid
diagnosis of OAV dysplasia or CFM, suggesting that the incidence for these disorders may be higher than
otherwise reported. Isolated microtia or aural atresia likely does not warrant imaging of the spine or
kidneys as the prevalence of abnormalities does not appear increased in this population. 21 However,
isolated microtia may serve as a useful marker to trigger screening in patients for other manifestations of
OAV dysplasia, as it has been shown to predict later facial growth asymmetry in up to 40% of screened
patients. 22
The middle ear is also often frequently affected, with moderate hypoplasia or atresia seen in up to 90% of
patients. 23 If present, hearing loss is conductive in the vast majority of cases (73%–86%) and may be
present on the contralateral side in unilateral CFM cases. Notably, the severity of craniofacial features
does not appear to correlate with the degree of hearing loss, so all patients suspected to be at risk should
undergo formal audiologic evaluation. 23
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Classification Schemes
Classification schemes for the overall total presentation have been proposed by Harvold, Vargevik, and
Chierici in 1983, and then by Munro and Lauritzen in 1985, among others. The classification most widely
adopted at this time is the OMENS+ classification. Vento, LaBrie, and Mulliken originally proposed the
OMENS scheme in 1991, describing the components most frequently affected: orbit, mandible, ear, nerve,
and soft tissue (Figure 30.3). 13 Each component is rated 0 to 3, with 0 indicating normal phenotype and 3
indicating maximal abnormality, for a total score ranging from 0 to 15. This was revised to OMENS+ in
1995 by Horgan et al. to include extracraniofacial abnormalities, as their study showed a correlation
between a higher OMENS score and likelihood of other, noncraniofacial anomalies. 24
FIGURE 30.3 These pictographs developed by Gougoutas and colleagues are useful visual aids in applying the OMENS+
classification system.
(From Gougoutas, AJ, Singh, DJ, Low, DW, Bartlett, SP. Hemifacial microsomia: clinical features and pictographic representations of the OMENS
classification system. Plast Reconstr Surg. 2007;120(7):112e-120e.)
Classification schemes for the individual features affected have also been proposed. The auricular
deformity has been classified by Meurman, 25 although Nagata’s microtia classification remains the more
clinically relevant one as its stages better correlate to conditions guiding surgical reconstruction. The
commonly recognized Pruzansky classification for mandible hypoplasia was first proposed by Pruzansky
in 1969 26 but was modified to the currently used schema by Kaban, Moses, and Mulliken in 1988 by
subdividing the type II hypoplastic mandible into type IIa and IIb based on the status of the TMJ. 27 This
alteration aligned the classification scheme with the surgical treatment algorithm and thus greatly
improved its usefulness. Figure 30.4 illustrates the modified Pruzansky classification for mandibular
hypoplasia, which will be the basis of the following discussion regarding treatment.
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FIGURE 30.4 Kaban and colleagues’ modification 27 of the original CFM classification system proposed by Pruzansky. 26 A.
Type I: The condyle and ramus are reduced in size, but the overall morphology is maintained. B. Type IIA: The ramus and
condyle demonstrate abnormal morphology, but the glenoid fossa has maintained a position in the temporal bone similar to that
of the contralateral side. C. Type IIB: The ramus/condyle is hypoplastic, malformed, and displaced toward the midline. D. Type
III: The ramus is essentially absent without any evidence of temporomandibular joint.
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Workup
Initiating care for a child with CFM begins with a thorough history:
Family history should focus on craniofacial disorders, facial asymmetry, auricular and periauricular
anomalies, hearing loss, ophthalmologic anomalies (epibulbar dermoids, colobomas), and mandible
asymmetry or malformation.
Maternal and pregnancy history should focus on use of any known teratogens (specifically retinoic
acid) and maternal diabetes mellitus.
Physical examination should include the following:
Following the OMENS+ classification template is useful to ensure completeness and relevant
documentation. Ophthalmologic examination should include assessment for epibulbar dermoids and
colobomas; there should be a low threshold for ophthalmologic consultation to perform a
funduscopic examination, especially if there is a suspicion of Goldenhar syndrome. The mandible,
auricle, soft tissues, and facial nerve function are all documented and assigned a grade.
Pictorial tools are available to aid in documentation of the present deformities. 28
Evaluation of the mandible should document interincisal opening and TMJ function. Together with
the cephalogram or CT/MRI imaging (if obtained), a modified Pruzansky grade should be assigned
for any child with mandibular hypoplasia.
At this time, there is no indication for routine genetic testing of patients with CFM, but engaging a genetic
counselor may improve the parents’ and patients’ understanding of the condition and can be an
important part of provided comprehensive care. Genetic testing and referral should be considered for any
patients whose presentation might suggest the presence of another syndrome (e.g., CHARGE or Treacher
Collins syndrome).
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Imaging and Testing
Auditory testing should be routinely performed for all patients with auricle malformations to assess
for hearing loss.
Swallow evaluation for dysphagia should be considered for all patients with CFM. Up to 13.5% of
patients may have swallowing difficulties, with the degree of dysphagia correlating to the severity of
the presentation. Video fluoroscopic swallow studies should be strongly considered for patients with
Pruzansky grade III mandible hypoplasia.
Children with findings on physical examination or history concerning for upper airway obstruction
(tachypnea, increased work of breathing, apnea, or snoring) should be evaluated with a sleep study
and/or airway endoscopy.
Standardized photography is crucial to document the patient’s appearance at presentation and
through his or her growth and treatment.
Cephalograms are routinely obtained to evaluate the shape and size of the mandible and maxilla.
These may be supplemented or replaced with CT imaging, particularly if virtual surgical planning is
anticipated to be used in future treatment.
It is important to diagnose any vertebral anomalies at an early stage because these can result in
cervical spine instability and risk neurologic compromise. Routine plain film X-ray evaluation of the
cervical spine is recommended for all patients with CFM; a spine specialist should be consulted
should any such anomalies be identified.
In cases with hearing loss, CT or MRI should be considered to image the middle and inner ear to
evaluate the degree of anatomic constriction or ossicle malformation.
Echocardiogram and renal ultrasound studies are recommended given the relatively high prevalence
and high impact of these anomalies in children with CFM.
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Management and Treatment
Treatment for CFM is complex because no single approach or algorithm can address the wide variety of
CFM presentation, and there is still debate regarding the timing of surgical intervention. Patients with
CFM should be treated in a multidisciplinary fashion, to ensure that all aspects of the affected systems are
correctly diagnosed and treated in a coordinated fashion. The already high likelihood of multiple
surgeries (microtia reconstruction, primary and/or secondary orthognathic surgery, soft-tissue or
macrostomia reconstruction, etc.) underscores the importance of coordinating care. Moreover, the
reconstructive surgeon should be familiar with the spectrum of procedures needed for a patient with
CFM to thoughtfully plan the earlier surgeries. This is well illustrated in patients with severe microtia, in
whom periauricular and temporal tissues are highly likely to be used in subsequent procedures, and thus
external incision planning for mandibular surgery must be undertaken with great care.
The treatment of orbital dystopia, microtia, and cranial vault deformities is addressed elsewhere in this
text so that the present discussion will focus on correction of the maxilla and mandible that is specific to
CFM.
As one of the focal points of CFM, treatment of the mandible forms the centerpiece of the overall surgical
plan, together with complementary intervention for the maxilla. The goal is to create functional occlusion,
construct a functional TMJ, and improve the facial skeletal bulk and contour to create facial symmetry.
The basic intervention layout has changed little since Kaban’s modification of the Pruzansky
classification, which hinges the operative decision-making on the functional status of the
temporomandibular articulation (Table 30.1).
TABLE 30.1
Modified Pruzansky Classification
Type
Description
Surgical Treatment Goals and Techniques
I or
IIa
Varied degree of hypoplasia
and condyle/ramus deformity
TMJ is functional
Expand existing bone stock to increase ramus height and facial contour, accomplished via sagittal
split osteotomy with or without a bone graft, or via distraction osteogenesis
IIb
or III
Severe hypoplasia or absence
of the ramus/condyle and
deformity of the body
TMJ is nonfunctional or absent
Zygomatic arch may be absent
Some type IIb with adequate bone stock may be distracted. Otherwise, as for all type III patients,
new bone stock must be brought in, accomplished via costochondral and osseous grafts to
reconstruct the ramus and TMJ/zygomatic arch
An important variable to consider is the status of the patient’s airway. In the newborn or infant with
CFM, the mandibular hypoplasia may lead to tongue retropositioning and tongue-based airway
obstruction, particularly in bilateral cases. If sleep study evaluation suggests significant apnea or
hypopnea and nasoendoscopy demonstrates airway obstruction limited to the tongue-base, early
mandibular advancement can improve the airway and facilitate decannulation if a tracheostomy has been
previously placed, accompanied by improvement in feeding/swallowing. Distraction is currently the
favored method of advancing the mandible in children, providing low relapse rates and expansion of the
soft-tissue envelope.
The techniques and outcomes of sagittal split osteotomy have been extensively researched since
Obwegeser’s initial description of the procedure. 29 One of the more common complications in SSO
(surgical site occurrence) is injury to the inferior alveolar nerve. It should be noted that in CFM patients,
the mandibular foramen is shifted superiorly, where it is found one-third of the way down as measured
from the sigmoid notch to the angle of the mandible, as opposed to halfway between these landmarks in
control patients. In addition, the nerve is located closer to the buccal cortex in patients with CFM. 30
Treatment of the type IIb mandible with adequate bone stock can be similar to the type I/IIa in that
distraction may suffice to expand the existing structure as long as the condyle is adequately developed
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