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CRANIOFACIAL SYNDROMES
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Michael Jaskolka, Renie Daniel, Lewis Jones
CHAPTER 35
EMBRYOGENESIS/GROWTH/DEVELOPMENT
1. What are the components of the craniofacial skeleton?
The craniofacial skeleton is composed of the neurocranium (cranial vault and cranial base) and
the viscerocranium (facial skeleton). The bones of the cranial vault are derived from the paraxial
mesoderm and are formed through intramembranous ossification; the formation and expansion of
ossification centers are directly within mesenchymal tissue. The bones of the cranial base are formed
through endochondral ossification.
2. Can you describe the rate of growth of the brain cranial vault of a child?
The brain is thought to grow in propulsive fashion. Over the first two years of life, the volume of the
brain and cranium increase fourfold. Head circumference has reached 86% of its final size by age 1
and 94% by age 5. The maturation age of cranium width is 14 years in females and 15 years in males.
3. How does the skull form and develop?
The cranial vault is formed by intramembraneous ossification, and bone deposition continues at the
sutures. Endocranial resorption and ectocranial deposition continue in step with brain growth and
expansion of the overlying soft tissue envelope. The three distinct layers of the skull do not develop
until 3 to 5 years of life.
4. What embryologic structures lead to the development of the face?
The frontonasal prominence and first pharyngeal arch. At weeks 4 to 5 the stomedial depression is
surrounded by primordial structures that develop into facial structures: the frontonasal prominence,
paired nasomedial and nasolateral prominences, and paired maxillary and mandibular prominences.
The maxillary and mandibular prominences are derived from the first pharyngeal arch with Meckel’s
cartilage acting as an ossification template for the mandible.
5. What are the differences among malformation, disruption, and deformation?
• Malformation: The abnormal formation of tissue as a result of an intrinsic developmental defect.
In general, the later the defect occurs in gestation, the less extensive the malformation (e.g., spinal
bifida).
• Disruption: This is the breakdown of previously developed tissue causing abnormal morphology
due to pressure resulting in amputation or vascular compromise (e.g., amniotic band).
• Deformation: This is changes in morphology caused by external mechanical forces on normal
tissue (e.g., oligohydramnios, intrauterine constraint, or abnormal fetal presentation).
6. What is the functional matrix theory of craniofacial growth?
Anatomist Melvin Moss proposed the concept in the 1960s that development of the facial skeleton
was directly related to the mechanics and functions of the various units that comprise the facial skeleton. Modern day interpretation has included an intrinsic (genetic) pattern that is altered by extrinsic
(epigenetic) factors.
7. How do remodeling and displacement contribute to craniofacial skeletal
harmony?
Remodeling occurs as a result of local factors that lead to a change in the size and shape of the facial
skeleton. Displacement occurs by the movement of bones away from each other at a suture or articulating surface (e.g., cranial sutures, temporomandibular joints, maxillary sutures). If the processes of
remodeling and displacement do not occur in a balanced fashion, a skeletal discrepancy will occur.
8. Can you name the six functional units that drive craniofacial development?
1. Central neurologic system
2. Optic pathway
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CHAPTER 35 CRANIOFACIAL SYNDROMES 363
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3. Speech and swallowing development
4. Airway and pharyngeal development
5. Muscles of facial expression development
6. Tooth development and exfoliation
9. At what age is the majority of orbital/zygomatic growth completed?
Approximately 85% of orbitozygomatic growth is completed between 5 and 7 years of age.
DEFORMATIONAL PLAGIOCEPHALY
10. What is meant by deformational plagiocephaly?
Deformational plagiocephaly is a nonsynostotic cranial deformity due to external forces. Most
commonly, this presents with asymmetric occipital flattening and anterior displacement of the
ipsilateral ear and forehead. Severe cases commonly occur in conjunction with torticollis. It is
necessary to differentiate between deformational plagiocephaly and lambdoid craniosynostosis,
which presents with ridging of the affected suture, severe flattening of the affected occipitoparietal region, ipsilateral retrusion of the forehead, and superior-posterior displacement of the ear
(Fig. 35-1).
11. Why has the incidence of deformational plagiocephaly increased since 1992?
This is the year that the American Association of Pediatrics (AAP) introduced the “back to sleep”
campaign to decrease sudden infant death syndrome (SIDS).
12. How is deformational plagiocephaly treated?
In mild cases, observed prone positioning and counterpositioning of the head will support normaliza-
tion of symmetry over time. In severe cases, families may elect to proceed with the use of a custom
molding helmet that is generally worn between the ages of 7 and 14 months of age.
13. Is there a relationship between deformational plagiocephaly and developmental
delay?
This is a controversial topic that is actively being investigated. A causal relationship has yet to be
demonstrated.
Figure 35-1. A, Cranial vault dysmorphology characteristic of posterior positional plagiocephaly. B, Cranial vault
dysmorphology characteristic of posterior plagiocephaly secondary to unilateral lambdoid suture craniosynostosis. (From
Caccamese J, Costello BJ, Ruiz RL, Ritter AM: Positional plagiocephaly: evaluation and management, Oral Maxillofacial
Surg Clin North Am 16(4):439–446, 2004.)
364 PART V ORAL AND MAXILLOFACIAL SURGERY
Mastoid fontanel
Lambdoid suture
Metopic suture
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14. What is torticollis?
Torticollis is an abnormal twisting of the head and neck. In children, this is most commonly caused
by shortening or contracture of the sternocleidomastoid muscle. Congenital muscular torticollis is
present at birth and may be due to intrauterine positioning, birth trauma, neurologic injury/disorder,
or tumor, or it may be idiopathic. Acquired torticollis is thought to be a result of supine positioning
with prolonged rotation of the head and neck. The clinical appearance is characterized by a rotation and tilting of the head toward the affected side with the chin pointing in the contralateral and
superior direction. There may be a fibrotic mass depending upon the etiology. Treatment involves
physical therapy, observed prone positioning, and counterpositioning of the head. In rare instances,
Botox injections or surgical lengthening of the SCM may be required. Delay in treatment or refractory cases may lead to facial and cranial asymmetry and may require management with a cranial
orthotic.
NONSYNDROMIC CRANIOSYNOSTOSIS
15. How many sutures are present in the cranial vault?
There are four major cranial vault sutures: metopic, coronal (bilateral), sagittal, and lambdoid (bilat-
eral). There are multiple other minor sutures (Fig. 35-2).
16. How many fontanelles are present in the developing skull?
There are four fontanelles: anterior, posterior, lateral/sphenoid (bilateral), and mastoid (bilateral) (see
Fig. 35-2).
17. What is craniosynostosis?
Craniosynostosis is the premature fusion of one or more sutures of the cranial vault. It leads to an
arrest of growth along the affected suture(s) that results in compensatory growth at the unaffected
sutures leading to characteristic dysmorphology. In general, it occurs as an intrauterine event.
18. An abnormality in what anatomic structure is thought to lead to
craniosynostosis?
The dura.
19. What is Virchow’s law?
In 1851, Rudolf Virchow described the cessation of growth perpendicular to a fused cranial suture,
with compensatory growth occurring at the remaining sutures in a parallel direction. In 1989,
Delashaw further expanded this concept with four additional observations to predict the patterns of
abnormal cranial morphology in more detail.
Figure 35-2. Major cranial vault sutures: the metopic, right and left coronal, sagittal, and right and left lambdoid. (From
Ruiz RL, Ritter AM, Turvey TA, Costello BJ, Ricalde P: Nonsyndromic craniosynostosis: diagnosis and contemporary surgical
management, Oral Maxillofacial Surg Clin North Am 16(4):447–463, 2004.)
Anterior fontanel
Coronal suture
Sphenoid fontanel
Sagittal suture
Posterior fontanel
Lambdoid suture
CHAPTER 35 CRANIOFACIAL SYNDROMES 365
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Table 35-1. Most Common Forms of Nonsyndromic Craniosynostosis
SUTURE SHAPE PREVALENCE COMMENTS
Sagittal Scaphocephaly 1:5000 Elongated (length)
Coronal
(unilateral)
Coronal
(bilateral)
Metopic Trigonocephaly 1:15,000 Hypotelorism, low incidence of
Lambdoid
(unilateral)
Lambdoid
(bilateral)
20. Can you describe the consequences of craniosynostosis?
Depending upon the number and type of suture(s) that are involved, craniosynostosis can lead to
abnormal morphology of the cranium, orbits, and face.
study by Marchac and Renier, approximately 14% of children with untreated single craniosynostosis
demonstrated increased ICP. The percentage increased to 42% when two or more sutures were fused.
Causality between craniosynostosis and elevated ICP is still debated in the literature.
decreased volume, strabismus, ptosis, abnormal binocular vision, and exorbitism.
21. What are the clinical findings that may be reported in children with untreated
craniosynostosis who develop increased ICP?
Headaches, vomiting, sleep disturbance, behavioral changes, and diminished cognitive function have
all been reported. Prolonged elevated ICP will produce papilledema, optic nerve atrophy, and eventual
vision loss. Signs of elevated ICP in association with single suture craniosynostosis are not usually
encountered before 1 year of life.
22. What are the physical and radiographic signs of craniosynostosis?
Absence of the affected suture with an irregular ridge of bone in its place. Abnormal cranial and orbital
morphology, depending upon the affected suture(s). Elevated ICP may demonstrate as a scalloped
“copper beaten” appearance or thinning and erosion of the inner surface of the skull on CT.
23. Can you describe the most common forms of nonsyndromic craniosynostosis?
See Table 35-1 and Fig. 35-3.
24. What is the harlequin eye deformity?
The harlequin eye deformity is the radiographic appearance of the superior lateral position of the
ipsilateral orbit and wing of the sphenoid seen in unilateral coronal craniosynostosis.
25. At what age does the metopic suture physiologically fuse?
The metopic suture has been shown to fuse as early as 3 months of life. When this occurs, there is
commonly a nonsynostotic ridge that forms. This can make the diagnosis of metopic craniosynostosis
challenging in mild cases.
26. When should surgical treatment of craniosynostosis take place, and what are the
two approaches that are used?
See Fig. 35-4. The exact timing depends upon the type of treatment, but surgery generally takes place
before 12 months of age.
Plagiocephaly (anterior) 1:10,000 Shortened orbit, retruded forehead,
Brachycephaly (anterior) Rare Syndromic
Plagiocephaly (posterior) 1:150,000 Commonly confused with deforma-
Brachycephaly (posterior) Rare Syndromic
In addition, it is thought to be associated with increased intracranial pressure (ICP). In the classic
Finally, involvement of the coronal suture and ring may result in shortening of the orbit,
Narrow (width)
harlequin eye, contralateral bossing, deviation of the nasal root
toward the affected side
Exorbitism
elevated ICP, often associated with
other malformations and/or delay
tional plagiocephaly
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A
C
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Scaphocephaly
Trigonocephaly
Figure 35-3. Three common forms of nonsyndromic craniosynostosis. (From Phillips N: Berry & Kohn’s Operating Room
Technique, ed 3, St. Louis, 2013, Mosby.)
Endoscopic treatment is undertaken at an earlier age, around 3 months of life. It consists of multiple small incisions, suturectomy, and often multiple wedge craniectomies. The use of a postoperative
cranial molding helmet is mandatory.
Open treatment is undertaken between 6 and 12 months of life. It consists of a coronal incision,
craniectomy, fronto-orbital advancement as indicated, and cranial vault reconstruction. If multiple
sutures are involved or the need for treatment is urgent, early surgery may be undertaken with a plan
for additional reconstruction.
27. What is the most important perioperative consideration for patients undergoing
correction of craniosynostosis?
Acute blood loss. Careful attention must be given to volume status. The majority of patients undergo-
ing open treatment require a blood transfusion.
Plagiocephaly
B
SYNDROMIC CRANIOSYNOSTOSIS
28. What is the most common location of the genetic mutation found in craniofacial
dysostosis syndromes, and how are they transmitted?
The genetic abnormality is most commonly found on the fibroblast growth factor receptor (FGFR)
genes 1, 2, and 3. The most common are the FGFR2-related dysostosis syndromes. They are generally
inherited in an autosomal dominant pattern.
29. What are the general functional considerations in patients with craniofacial
dysostosis syndromes?
• CraniosynostosismayrestrictbraingrowthandbeassociatedwithelevatedICPleadingtocognitive
and behavioral delays as well as optic nerve compression.
• Untreatedopticnervecompressionwillinitiallycausepapilledemaandeventuallyresultinoptic
nerve atrophy and blindness.
• Shalloworbitsresultinproptosisoftheglobethatmayleadtocornealdesiccation/ulcersaswellas
globe herniation in severe cases. Dystopia and strabismus are also common orbital findings.
CHAPTER 35 CRANIOFACIAL SYNDROMES 367
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Figure 35-4. Reconstructive procedure used to address the dysmorphology associated with unilateral coronal suture craniosynostosis. A, Outline of the bifrontal craniotomy and orbital osteotomies. B, The dysmorphic orbital bandeau is removed,
and vertical osteomies are used for reshaping. C, The reconstructed orbital bandeau is reinserted, and anterior cranial vault
reconstruction is performed. (From Ruiz RL, Ritter AM, Turvey TA, Costello BJ, Ricalde P: Nonsyndromic craniosynostosis:
diagnosis and contemporary surgical management, Oral Maxillofacial Surg Clin North Am 16(4):447–463, 2004.)
• Hydrocephalusisaconcernandispostulatedtobesecondarytoconstrictionofthecranialbase
foramina and diminished venous drainage.
• Severemidfacehypoplasiamaycontributetoairwayobstructionandsleepapnea.Earlyevaluation
with polysomnogram may be indicated.
• Dentalcrowding,eruptiveabnormalities,andmalocclusionarecommon.
30. What is Crouzon syndrome?
Crouzon syndrome is a form of craniofacial dysostosis that is characterized by bilateral coronal cra-
niosynostosis; other sutures are less often involved. This results in a brachycephalic skull with anterior
retrusion, midface hypoplasia and exorbitism. Conductive hearing loss is a common finding. Patients
demonstrate a typical IQ.
31. What is Apert syndrome?
Apert syndrome is a form of craniofacial dysostosis that is characterized by bilateral coronal cranio-
synostosis with a widely patent midline calvarial defect, orbital hypertelorism, ptosis of the upper
eyelids and downward slanting lateral canthi, midface hypoplasia, beaked nose, cleft palate (30%),
hearing loss (30%), developmental delay, complex syndactaly of fingers and toes, and thick facial skin
with increased sebaceous discharge. Macrocephaly and other CNS malformations may be present.
Apert syndrome is thought to be associated with advanced paternal age.
32. What is Pfeiffer syndrome?
Pfeiffer syndrome is a form of craniofacial dysostosis that has 3 clinical subtypes with variable
penetrance. In general, Pfeiffer syndrome is characterized by craniosynostosis, orbital dystopia,
midface hypoplasia, broad and deviated thumbs and toes, and variable syndactyly of the hands and
feet. Type 1 is considered the classic form as described above, and patients have a good prognosis.
Type 2 is the most severe in presentation and includes the cloverleaf skull deformity, significant
368 PART V ORAL AND MAXILLOFACIAL SURGERY
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neurologic deficit, and a limited lifespan. Type 3 is similar in severity but does not include the
cloverleaf skull deformity. There are a number of other low-frequency limb and organ abnormalities
that may occur.
33. What are the other most common named craniofacial syndromes?
Carpenter, Saethre-Chotzen, Beare-Stevenson, Jackson-Weiss, and Meunke.
34. What is the genetic basis for Saethre-Chotzen syndrome?
Mutation in the TWIST 1 gene and subsequent TWIST 1 protein. A small subset of patients have a
chromosomal abnormality in the region of chromosome 7 that contains the TWIST 1 gene.
35. What is the general sequence of surgical treatment of patients with craniofacial
dysostosis syndromes?
In patients demonstrating increased ICP, early suturectomy and cranial vault expansion are performed.
Otherwise, craniectomy and anterior cranial vault reconstruction with fronto-orbital advancement are
completed before 12 months of age. Repeat craniofacial expansion may be required during childhood
if findings of increased ICP are noted. Residual forehead retrusion, orbital hypertelorism, and midface
deficiency can be managed after orbitozygomatic development is largely complete (5 to 7 years of
age) by monobloc, facial bipartition, or Le Fort III procedures as indicated by the individual deformity. Final malocclusion is treated with more traditional orthognathic surgical techniques at skeletal
maturity.
36. What are the most common craniofacial conditions that include orbital
hypertelorism?
The craniofacial dysostosis syndromes, (cranio) frontonasal dysplasia, and midline facial clefts.
37. What are the key features of frontonasal dysplasia?
The most common presentation includes anterior cranium bifidum, orbital hypertelorism, a widow’s
peak, wide nasal dorsum with a bifid tip, and a midline cleft of the lip and palate.
Craniofrontonasal dysplasia is likely a subtype that is inherited in an X-linked dominant
pattern and more commonly seen in females. It has similar features, but includes craniosynostosis (most commonly bilateral coronal), thick and wiry hair, and other low-frequency extremity
abnormalities.
38. What are the surgical options for correction of orbital hypertelorism?
Circumferential orbital osteotomies can be completed through a combined intracranial/extracranial
approach. The orbits can be translocated after excision of a portion of the intervening interorbital
tissues (frontal and nasal bones, floor of the anterior cranial fossa, ethmoid air cells, and nasal
septum). Patients who have severe constriction of the maxilla can be managed with a facial bipartition
procedure.
39. What adjunctive procedures are often necessary at the time of orbital hypertelorism correction?
Concurrent dorsal nasal augmentation and medial canthopexies.
40. What is the position of the cribriform plate in patients with orbital hypertelorism,
and why is this important?
The cribriform plate is often inferiorly positioned with prolapse of the frontal lobes. Retraction and
elevation are critical for the safe medial translocation of the orbits.
41. Can you describe the cloverleaf skull deformity?
Cloverleaf skull, also known as kleeblattschädel, refers to the trilobar skull shape characterized by
multiple suture craniosynostosis, towering and bossing of the forehead, flattening of the posterior
skull, and expansion or bulging of the temporal regions. The etiology is heterogeneous, and cloverleaf
skull anomalies are often seen in conjunction with a spectrum of brain malformations. It can occur in
the absence of craniosynostosis.
42. What are the characteristic features of Binder syndrome?
Variable nasomaxillary hypoplasia that may affect the frontal sinus, nose, upper lip, anterior septum,
floor of the nose, and premaxillary-derived tissues. Clinical presentation includes midface deficiency,
absence of anterior nasal spine, short nose with limited projection, acute nasolabial angle, and a flat
nasofrontal angle. The nostrils appear crescent or semilunar in shape when viewed from below.
CHAPTER 35 CRANIOFACIAL SYNDROMES 369
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Fonseca RJ, Marciani RD, Turvey TA, editors: Oral and maxillofacial surgery, ed 2, St Louis, 2009, Saunders.
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OROMANDIBULARDYSOSTOSIS
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Daniel J. Meara, Renie Daniel, Lewis Jones, Michael Jaskolka
CHAPTER 36
1. What is the etiology of human facial dysostoses?
The human facial dysostoses are felt to result from abnormal migration of neural crest cells to the
pharyngeal arches of the face.
2. Which branchial arches are disturbed in the human facial dysostoses?
The first and second branchial arches are affected in these dysostoses. (See Table 36-1.)
3. How are these groups of conditions subdivided?
• Mandibulofacialdysostoses(MFD)
• Acrofacialdysostoses(AFD)
4. What differentiates the mandibulofacial from the acrofacial dysostoses?
The addition of limb abnormalities results in the designation of acrofacial dysostosis.
5. What are the common characteristics of oromandibular dysostoses?
• Down-slantingpalpebralssures
• Colobomaofthelowereyelids
• Hypoplasiaofthezygomaticcomplex
• Retro-micrognathia
• Microtia
6. What is a coloboma?
Acolobomaisanapparentabsenceordefectofsomeoculartissue,usuallyduetofailureofapartof
thefetalssuretoclose.Typically,thedefectisaskinnotchwithinthelowereyelidthatinvolvesthe
wholethicknessoftheeyelid,andreconstructioninvolvesallofitslayers.
7. What is the most common and well known of the oromandibulofacial dysostoses?
TreacherCollinssyndrome.Thisconditionistheresultofatleastthreegenemutations(TCOF1,POLR1D,
andPOLR1C).ItwasinitiallydescribedbyBritishophthalmologistDr.EdwardTreacherCollinsin1900,
anditwasmoredenitivelydescribedbySwissophthalmologistDr.AdolpheFranceschettiin1949.
8. What is Treacher Collins syndrome?
TreacherCollinssyndrome,alsoknownasmandibulofacialdysostosis,isinheritedinanautosomal
dominantfashionanddemonstratesvariablephenotypicexpression.Itpresentswithbilateralabnormalitiesofthestructuresoftherstandsecondbranchialarches.Incidenceisbetween1in25,000to
1in50,000livebirths.
9. Can you describe the characteristic findings in a patient with Treacher Collins
syndrome?
TreacherCollinsndingstypicallyconsistof:
• Markedunderdevelopmentofthezygomaticcomplex
• Overlyingskinandsofttissuesarehypoplasticwithdownward-slopingpalpebralssuresand
inferiorly positioned lateral canthi.
• Colobomasofthelowereyelids
• Varyingdegreesofmicrotiamayoccuraswellasconductivehearinglossduetoexternaland
middle ear abnormalities.
• Thenoseiswideatthebridgewithelongationandlackstipsupport.
• Theoverallfacialformisconvexduetoclockwiserotationofthemaxilla-mandibularcomplex,class
IIopenbiterelationship,increasedlowerfacialheight,mandibularhypoplasia(especiallyofthe
condylar-ramusunit),anobtusemandibularplaneangle,andretrogenia,oftenresultinginairway
impairment and feeding difficulties.
• TheTMJsandmusculaturearecommonlyhypoplastic.
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Table 36-1. Pharngeal Arch and its Derivatives
PHARYNGEAL
ARCH ARCH ARTERY
1 Terminal branch of
2 Stapedius artery
3
4
6
maxillaryarch
(embryologic)
and corticotympanic artery
(adult)
Commoncarotid
artery,mostof
internal carotid
Left:Archofaorta
Right:Rightsubcla-
vianartery
Ductusarteriosus;
rootsofdenitive
pulmonary arteries
CRANIAL
NERVE
Maxillaryand
mandibular
divisionof
trigeminal(V)
Facialnerve
(VII)
Glossopharyn-
geal(IX)
Superior laryn-
geal branch
ofvagus(X)
Recurrentlaryn-
geal branch
ofvagus(X)
SKELETAL
ELEMENTS MUSCLES
Incus,malleus.Upper
portionofexternal
ear(auricle),
maxilla,zygomatic,
squamousportion
oftemporalbone,
mandible
Stapes,styloid
process,stylohyoid
ligament,lesser
horns and upper
rim of hyoid
Lowerportionofex-
ternal ear (auricle)
Lowerrimandgreater
horn of hyoid
Laryngealcartilages
Laryngealcartilages
Muscleofmastica-
tion,mylohyoid,
anterior belly of
digastric,tensor
tympani,tensor
velipalatini
Musclesoffacial
expression,
posterior belly
ofdigastric,
mylohyoid
stapedius
Stylopharyngeus
Constrictorsof
pharynx,cricohyoid,levator
velipalatini
Intrinsicmuscles
oflarynx
• Cleftpalatemayalsobepresent.
• Dentalanomaliesincludemissingorhypoplasticteeth.
10. What syndrome is similar in craniofacial presentation to Treacher Collins syn-
drome, with the addition of extremity abnormalities?
Nagersyndrome,alsoknownasacrofacialdysostosis.Autosomalrecessiveanddominantcausation
hasbeendescribed,andtheconditionisoftensporadic,withoutfamilialtendencies.
Thefacialfeaturesinclude:
• Malarhypoplasia
• Downward-slantingpalpebralssures
• Mandibulardeciency,oftenresultinginairwaycompromiseandfeedingdifculties
• Low-setandabnormalears
• Conductivehearingloss
• Cleftpalatewithsignicanthypoplasia
Thelimbabnormalitiesmayrangefromhypoplasiatoagenesisoftheradiusandthumbs,withmul-
tipleotherlow-frequencyextremityabnormalities.
11. What is craniofacial microsomia (CFM)?
CFMisacongenitalbirthdefectpostulatedtobearesultofinuteroinjurytothestapedialarterythat
leadstovariablehypoplasiaoftherstandsecondbranchialarches,viafailedneuralcrestdevelop-
ment and migration.
Patientscommonlyclinicallydemonstrate:
• Microtia
• Skintags
• Colobomas
• Facialnerveweakness
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