Craniofacial Anomalies




Craniosynostosis, in which 1 or more cranial sutures prematurely fuse, is associated with diverse environmental and genetic factors. Whereas isolated single-suture synostosis is usually sporadic and nonfamilial, FGFR mutations account for most cases of syndromic craniosynostosis. This article reviews the etiology and various clinical manifestations of the most common isolated and syndromic forms of craniosynostosis, and provides a brief overview of genetics. Past and present surgical management approaches and techniques are examined in depth. Outcomes data in the recent literature are reviewed, and controversies in the field and promising trends in craniofacial surgery discussed.


Key points








  • Craniofacial anomalies are common (1:2000 for isolated suture synostosis) but syndromic craniosynostosis is relatively rare.



  • FGFR mutations underlie most syndromic craniosynostosis, whereas nonsyndromic synostosis frequently involves a variety of genetic and environmental risk factors.



  • Single-suture synostosis is often an isolated finding, and intracranial hypertension, developmental delays, and strabismus, though less likely in isolated synostosis, are more frequent in multisuture and syndromic forms of craniosynostosis.



  • Minimally invasive approaches are most successful when done between ages 3 and 6 months, and often require many months of molding-helmet therapy postoperatively.



  • Surgery after age 8 to 9 months usually requires open cranial vault reconstruction whereby the skull is surgically osteotomized; bone grafts are reshaped and repositioned, then fixated in anatomically improved and often overcorrected positions.




Videos related to pediatric craniofacial surgical procedures (Video 1: Open approach for sagittal synostosis subtotal cranial vault recon without bone grafting and Video 2: Depicts endoscopic-assisted strip craniectomy with wedge craniectomy) accompany this article at www.facialplastic.theclinics.com/




Overview


Craniosynostosis, the premature closure of cranial sutures, may be isolated or nonsyndromic, affecting 1 in 2000 live births (typically single-sutured), or syndromic, affecting 1:30,000 to 1:100,000 live births (frequently multisutured), and primary or secondary. Multifactorial, genetic, and environmental influences may be involved. Regardless of etiology, the fused suture(s) typically cause(s) a restriction in skull growth and subsequent skull characteristics, skull base, and asymmetries and disturbances at the time of facial growth. Three theories have been proposed:



  • 1.

    Virchow’s theory that sutural fusion precedes other events


  • 2.

    Moss’s idea that primacy lies with primary skull-base growth restriction preceding synostosis


  • 3.

    Others have suggested that brain growth restriction is the primary factor that subsequently leads to premature fusion



It is now generally accepted that underlying mechanical force signaling pathways and cytokines mediate cranial suture patency, and premature fusion is thought to occur secondary to mutations in these genes. Secondary synostosis is evidenced in both microcephalic and overshunted individuals, and in certain hematologic disorders.


The majority or craniofacial growth and development occurs during the first year of life and growth potential, with the brain doubling in size by 1 year of life and tripling by 2 years. This rapid growth of the brain and resultant bone growth are determined by complex growth factor pathways regulated by genes that code for fibroblast growth factor receptor (FGFR) and transforming growth factor (TGF)-β, among others, and are at the core of the principles of craniofacial surgery, including the duration and timing of surgical intervention. There are clearly both environmental and genetic factors at play for isolated, single-suture, nonsyndromic forms of synostosis ( Fig. 1 ).




Fig. 1


Four-month-old identical twins, frontal and vertex views. Twin on left lap with sagittal synostosis and scaphocephaly.




Overview


Craniosynostosis, the premature closure of cranial sutures, may be isolated or nonsyndromic, affecting 1 in 2000 live births (typically single-sutured), or syndromic, affecting 1:30,000 to 1:100,000 live births (frequently multisutured), and primary or secondary. Multifactorial, genetic, and environmental influences may be involved. Regardless of etiology, the fused suture(s) typically cause(s) a restriction in skull growth and subsequent skull characteristics, skull base, and asymmetries and disturbances at the time of facial growth. Three theories have been proposed:



  • 1.

    Virchow’s theory that sutural fusion precedes other events


  • 2.

    Moss’s idea that primacy lies with primary skull-base growth restriction preceding synostosis


  • 3.

    Others have suggested that brain growth restriction is the primary factor that subsequently leads to premature fusion



It is now generally accepted that underlying mechanical force signaling pathways and cytokines mediate cranial suture patency, and premature fusion is thought to occur secondary to mutations in these genes. Secondary synostosis is evidenced in both microcephalic and overshunted individuals, and in certain hematologic disorders.


The majority or craniofacial growth and development occurs during the first year of life and growth potential, with the brain doubling in size by 1 year of life and tripling by 2 years. This rapid growth of the brain and resultant bone growth are determined by complex growth factor pathways regulated by genes that code for fibroblast growth factor receptor (FGFR) and transforming growth factor (TGF)-β, among others, and are at the core of the principles of craniofacial surgery, including the duration and timing of surgical intervention. There are clearly both environmental and genetic factors at play for isolated, single-suture, nonsyndromic forms of synostosis ( Fig. 1 ).




Fig. 1


Four-month-old identical twins, frontal and vertex views. Twin on left lap with sagittal synostosis and scaphocephaly.




Pathophysiology


Multiple environmental associations have been described, including paternal occupations such as agriculture and forestry, maternal age, exposure to tobacco smoke, and medications, including nitrofurantoin and warfarin use during pregnancy. Malpositioned fetal lie and intrauterine constraint or, at times, metabolic factors can also be associated, including mucopolysaccharidosis, mucolipidosis, rickets, and hyperthyroidosis.




Molecular genetics


A variety of mutations in transcription derived growth factors, FGFR1,2 and 3 are known to be involved in syndromic craniosynostosis ( Table 1 ).



Table 1

Summary of the most common syndromic craniosynostoses




























































Syndrome Skull Deformity Craniofacial Abnormalities Signs and Symptoms Genetics Hand and Feet Abnormalities Incidence
Apert Turribrachycephaly
Acrocephaly
Opened metopic suture
Bitemporal bulging
Bilateral coronal
Bilateral lambdoid
Sagittal synostosis
Orbital hypoplasia and orbital rim retrusion
Hypertelorism
Proptosis
Downslanting palpebral fissures
Cranial bony defects
Short “beaked” nose
Midface hypoplasia
Mandibular prognatism
Highly arched palate
Mental retardation
Intracranial hypertension
Cerebral atrophy
Wide subarachnoid spaces
FGFR2
Autosomal dominant
Mainly sporadic (paternal), some familial
Pansyndactylies of hands and feet 1:65,000–100,000 live births
Crouzon Acrocephaly
Coronal, lambdoid, and basilar synchondroses/synostosises
Shallow orbit, orbital proptosis
Hypertelorism
Strabismus
Beaked nose
Maxillary hypoplasia
Mandibular prognatism
Highly arched palate
Enlarged sella turcica
Jugular foramina stenosis
Hydrocephalus
Symptomatic chronic tonsillar herniation
Syringomyelia
Intracranial hypertension
Optic atrophy
Mental retardation
FGFR2 , FGFR3 if associated with acanthosis nigricans
Autosomal dominant
Sporadic and familial cases are almost equal
Usually unaffected 1.6 per 100,000
Pfeiffer


  • Type I:




    • Turribrachycephaly



    • Bilateral coronal



    • Frontosphenoidal synostoses




  • Type II:




    • Cloverleaf deformation




  • Type III:




    • Severe turribrachicephaly



    • Bilateral coronal



    • Frontosphenoidal sagittal, metopic, and bilateral metopic synostoses


Orbital proptosis and stenosis
Palpebral retraction
Jugular foramen stenosis
Midfacial hypoplasia
Mandibular prognatism
Highly arched palate
Bifid uvula
External ear duct atresia
Intracranial hypertension
Hydrocephalus
Sympotomatic chronic tonsillar herniation
Optic atrophy
Severe mental retardation (Types II and III)
Transmission hearing loss
Respiratory insufficiency
Sleep apnea
FGFR2
FGFR1
Autosomal dominant
Sporadic and familial cases are close to equal
Brachdactyly, limited variable syndactyly 1:100,000
Saethre-Chotzen Acrocephaly
Plagiocephaly
Scaphocephaly
Unilateral coronal, bilateral coronal, metopic, and bilateral lambdoid synostoses
Low-set frontal hairline
Flat forehead
Hypertelorism
Eyelid ptosis
Tear duct stenosis
Highly arched palate
Mandibular prognatism
Angulated and small round ears
Mental retardation
Conductive hearing loss
TWIST Gene mutation Chr 7
Autosomal dominant
Mainly familial, one-third is sporadic
Partial cutaneous syndactyly, some brachydactyly 1:25,000–1:50,000
Carpenter syndrome Sagittal and lambdoid synostosis Downsloping palpebral fissures, low-set ears, short neck Often short in height
Obesity
Mental retardation in many, normal intelligence in some
Autosomal recessive RAB23 or MEGF8 mutations Variable polysyndactyly, clinodactyly, brachydactyly 1:1,000,000
Muenke syndrome Unilateral or bilateral coronal synostosis Variable hypertelorism
Mild to moderate midface hypoplasia, low-set ears, associated hearing loss
Usually normal intelligence Autosomal dominant
FGFR3 mutations
Variable carpal and tarsal fusions 1:30,000


Scaphocephaly


Scaphocephaly (boat-shaped head) ( Fig. 2 ) can occur without synostosis; however, it is the most common manifestation of sagittal synostosis in up to 50% of isolated synostosis. Calvarial bone growth is limited perpendicular to the affected sagittal suture, resulting in narrowing of the head transversely, and resultant brain growth anteroposteriorly leads to frontal bossing and/or occipital cupping. Shape may vary depending on the duration or timing of synostosis, whether partial or complete suture involvement, and whether other sutures are involved ( Figs. 3 and 4 ).




Fig. 2


Normocephaly and common forms of craniosynostosis and deformational plagiocephaly, with representative shapes.



Fig. 3


Preoperative frontal, lateral, and vertex views, and 3-dimensional (3D) computed tomography (CT) demonstrating sagittal synostosis and, in this case, predominantly occipital deformity.



Fig. 4


A 3.5-year-old infant with predominantly frontal boxiness and bitemporal narrowing: Preoperative frontal, lateral, occiput, and vertex views, and 20 month postoperative view following extended sagittal strip craniectomy with biparietal wedge craniectomies and outfracture of parietal bones at 4.5 months of age and 4 months of postoperative molding helmet.


Trigonocephaly


Metopic synostosis may result in mild metopic ridging in the midline forehead or a combination of ridging, bitemporal narrowing, and hypotelorism, which together make the forehead appear triangular ( Fig. 5 C, D). The metopic suture fuses as early as age 3 to 6 months and, unlike other cranial sutures, normally disappears; hence, the diagnosis largely depends more on clinical shape and less on computed tomography (CT) findings.




Fig. 5


Preoperative frontal and vertex views and 3D CT demonstrating severe trigonocephaly and hypotelorism at age 9 months ( A D ), 21 months after bi–fronto-orbital advancements and frontal cranioplasties ( E , G ), and 3D CT 9 months postoperatively ( F , H ).


Deformational Plagiocephaly


Meaning twisted or slanted, deformational plagiocephaly (DP) refers to flattening of the head.


The most common type of plagiocephaly is positional, namely DP. DP results when the skull is subject to pressure either in utero or, more commonly, as a result of supine positioning. Favored fetal and postnatal lie are thought to underlie DP. Congenital torticollis is associated with and likely responsible for this condition one-third of the time, leading to characteristic head tilt on the side of the affected sternocleidomastoid muscle and twisting of the neck such that babies tend to prefer sleeping on the contralateral occiput. Repositioning maneuvers and repositioning pillows work by keeping babies off the affected flat area(s), and are fairly effective in ameliorating DP when used in the first 4 to 6 months of life. Neck physiotherapy is important when congenital torticollis is present. When severe flattening persists beyond the first 5 to 6 months of life, orthotic molding bands or helmets ( Fig. 6 ) have been shown to improve cranial symmetry, especially when used before age 12 months. A recent randomized controlled study showed no differences in 5- to 6-month-old babies with moderate asymmetries treated for 6 months with or without helmets. Of note, these investigators excluded babies with the most severe cranial asymmetries.




Fig. 6


Frontal and vertex views of a 4-month-old female with right torticollis and positional plagiocephaly (right > left) ( A , B ), after 6 weeks of orthotic molding band ( C , D ), and after 4 months of banding, pictured with the second band ( E , F ).


Although DP is more commonly unilateral, bilateral DP is not uncommon and presents with brachycephaly or bilateral occipital flattening. This condition leads to a head that is short anteroposteriorly and wide transversely, which makes both the head and face look round in appearance (see Fig. 10 ).


Anterior Plagiocephaly


Unilateral coronal synostosis results in anterior plagiocephaly. The affected frontal bone is underprojected, and the contralateral frontal bone bulges anteriorly ( Fig. 7 ), which can push the orbit inferiorly, resulting in orbital asymmetry or vertical dystopia.




Fig. 7


Frontal, basal, fronto-vertex, and vertex photos, and 3D CT of a 9-month-old infant with right coronal and sagittal synostosis.


The superior orbital rim is elevated (Harlequin eye) ( Fig. 8 ); in severe and late presenting coronal synostosis the nasal root deviates toward the fused suture and the mandible can be similarly shifted, with additional associated ipsilateral temporal narrowing.




Fig. 8


Note the left frontal flattening and vertical dystopia on this 2-day-old baby with characteristic Harlequin sign on plain radiograph of the skull.


Posterior Plagiocephaly


Like DP, lambdoid suture synostosis results in unilateral occipital flattening, but with concomitant ipsilateral mastoid bulging and posterior inferior displacement of the ipsilateral ear. There are no frontal bony changes, whereas in DP there is concomitant ipsilateral frontal bone shift anteriorly, and in DP the ipsilateral ear is often more anterior than the unaffected side. When viewed from above these differences are described as parallelogram deformity in the case of DP and trapezoid deformity for unilateral lambdoid synostosis (see Fig. 2 ). It is worth remembering that whereas DP is common (20% to 50% of all babies are affected to some degree), lambdoid synostosis is extremely rare (1:100,000).


Brachycephaly


Although the most common cause of brachycephaly (short head) is deformational and related to supine positioning, bilateral coronal synostosis needs to be ruled out ( Fig. 9 ).




Fig. 9


A 13-year-old child with syndromic multisuture synostosis including bicoronal and brachycephalic head (vertex view).


Usually a detailed history will reveal progressive flattening in positional brachycephaly, whereas syndromic brachycephaly will often present with characteristic syndromic facies and digital/pedal deformities (see Table 1 ). A noncontrasted head CT with 3-dimensional reconstruction ( Fig. 10 ) will confirm the diagnosis.




Fig. 10


A 16-month-old infant with positional brachycephaly.


Cloverleaf skull


Cloverleaf skull is the result of fusion of all cranial sutures, except the metopic and squamosal. Because the brain is restricted in multiple planes, characteristic compensatory bulging occurs as brain and bone growth are forced across the 2 opened sutures, yielding the characteristic cloverleaf shape. Cloverleaf is perhaps the most challenging and dangerous craniosynostosis because of the severe bony growth restriction and limited intracranial volume, leading to problems with increased intracranial pressure (ICP), brain dysfunction, and hydrocephalus. Because of the severity of proptosis and orbital hypoplasia, impaired vision is common, especially in the case of extensive manipulation.


History of craniofacial surgery


History of craniofacial surgery is beyond the scope of this article Table 2 for brief overview.



Table 2

Brief review of historical development of diagnosis and surgical treatment




































762 bc Homer in Iliad . Hippocrates and Galen delineate the shape
16th Century Anatomic descriptions established (Hundt, Dryander Vesalius)
1851 Virchow describes basics of abnormal and compensatory skull growth. Names condition as craniostenosis, also known as Virchow’s Law. Sear proposes title craniosynostosis in 1937
1912 Apert and Crouzon publish syndromic craniosynostosis
1890, 1892 First reported interventions for treatment; published in Paris and San Francisco
1921 Mechner publishes first modern surgical approach
1940s Surgery available for those who present late in course of disease. Investigators propose polyethylene and tantalum to prevent suture reunion
1956 Anderson coagulates dura, based on assumption that it gives pathologic signal, but technique causes seizures. Matson applies pericraniectomy to help inhibition of bone reproduction at strip suture resection. Further development not possible without concurrent advent of modern anesthesiology and transfusion techniques. Leads to 2 deaths in 394 operations. From this point on, safety level and cosmetic outcome emerge as goals of surgery
1960–1990 Total cranial vault reconstruction with wedge craniectomies added to strip resections and Pi procedure for advanced sagittal and orbital rim. Extensive strip removal proposed and developed by Epstein, and extensive operations, new techniques, and classifications published by McComb
1971 Tessier further develops and makes safer existing surgical techniques by providing basis for safety and successful outcome
Today Distraction craniotomies, endoscopic approach, and minimally invasive techniques make repertoire more colorful with obvious contribution to safety, less operative time, diminished blood loss, and shortened hospital stay

Data from Mehta VA, Bettegowda C, Jallo GI, et al. The evolution of surgical management for craniosynostosis. Neurosurg Focus 2010;29(6):E5. 1–7.




Evaluation and diagnosis of craniosynostosis


It is important to obtain detailed history of pregnancy, birth, family, and medications or drug exposure in utero. The duration and timing of head shape is important because progressive flattening would suggest DP, with deformities that are present since birth and relatively unaffected by positioning more likely to suggest synostosis. The head should be observed from all possible views and photographic documentation obtained, fontanelles and sutures should be palpated, fronto-occipital circumference measured, and calipers used to measure cephalic index (CI) (the ratio of width/length of the skull). Careful examination of the face including orbital size, presence of asymmetry, ptosis, lagophthalmos, hypertelorism or hypotelorism, or pseudohypertelorism is warranted. Ear position, size, and any associated deformities, and facial paresis or paralysis should be noted. Full body examination is important to evaluate for findings involved in syndromic craniosynostosis, such as cardiac anomalies, respiratory difficulties as a result of mandibular or midface hypoplasia, and ocular exposure from exorbitism/proptosis. Hand/foot and finger/toe anomalies are common (see Table 1 ) with many of the syndromic craniosynostoses.


Microcephaly, venous anomalies and pressure elevation, hydrocephalus, and cerebellar tonsillar herniation all can lead to increased ICP and can present acutely, subacutely, or chronically. It is important to look for nonspecific signs and symptoms such as irritability, feeding difficulties, inconsolable crying, or insomnia as red flags for ICP elevation. A bulging fontanelle and engorged scalp veins are also often predictive. Pediatric ophthalmology evaluation to examine for strabismus and rule out papilledema is useful, and even in the absence of papilledema ICP monitoring should be considered if there is a strong suspicion for ICP elevation.


Imaging in Craniosynostosis


Skull series are sometimes obtained when evaluating for abnormal head shapes. Thumbprinting or copper-beaten appearance on plain films, representing inner table scalloping ( Fig. 11 ), is one warning of potential increased ICP.




Fig. 11


Plain skull film ( A ) and stereolithographic model ( B ) demonstrating thumbprinting/copper-beaten appearance in child with syndromic multisuture craniosynostosis and brachycephaly. ( C ) intraoperative view of inner table of frontal calvarium depicting bony changes that are typical of chronic elevation of intracranial pressure.


CT scans are used to confirm a diagnosis of craniosynostosis and though not necessary for every craniofacial deformity, CT can be used with computer-aided design and modeling (CAD-CAM) for preoperative planning to create stereolithographic models, make miters, optimize osteotomies, and create custom CAD-CAM patient-specific implants designed to exactly match bony defects ( Figs. 12 and 13 ).




Fig. 12


( A ) A 7-year-old child with large left fronto-temporo-parietal defect following decompressive craniectomy. ( B ) Proposed CAD-CAM model with allograft implant. ( C ) Intraoperative view with CAD-CAM PEEK implant reconstructing the defect.



Fig. 13


A 13-year-old child with bilateral craniofacial microsomia, bilateral grade 2 microtia, and micrognathia with occlusal plane abnormalities. 3D model and preoperative planning session with proposed mandibular osteotomies and curvilinear distraction simulated.


Some centers obtain immediate baseline postoperative CT scans following cranial vault reconstruction. Owing to the risks of ionizing radiation, the authors defer on ordering these unless the patient has neurologic deterioration; otherwise follow-up CT scans are obtained about 12 to 18 months postoperatively. For postoperative fluid collections, hematomas, or hydrocephalus, rapid magnetic resonance imaging (MRI) or lowered-radiation CT of the brain is the choice of diagnostic testing. MRI is useful for evaluating the brain for abnormalities such as Chiari malformations ( Fig. 14 ), venous anomalies, and hydrocephalus (see Table 2 ).




Fig. 14


( A ) Sagittal T1-weighted magnetic resonance imaging (MRI) in a 2-week-old baby with syndromic craniosynostosis and bicoronal and metopic synostosis, demonstrating exorbitism and ocular proptosis. ( B ) Sagittal T1-weighted MRI depicting 13-year-old with syndromic multisuture synostosis and Chiari I malformation.




The concept of the craniofacial team


Because craniosynostosis is often part of a syndrome and many systems are often affected, an interdisciplinary team approach is now the standard of care for such complicated patients.


This team can include a plastic surgeon, pediatric otolaryngologist, or facial plastic surgeon trained in craniofacial surgery, a pediatric neurosurgeon, an oral-maxillofacial surgeon, a pediatric anesthesiologist and intensivist, a pedodontist orthodontist, a prosthodontist, a pediatric ophthalmologist, a psychologist, a geneticist, an audiologist, a speech pathologist, pediatrician, among others.




Treatment goals and planned outcomes


Determining which patients have or might develop functional problems as a result of increased ICP, and developmental delays, strabismus, or loss of vision as result of optic disc atrophy or exposure keratopathy is important in efforts to avoid the sequelae of these problems.


Improving outcomes from a functional standpoint is primary, but aesthetic improvements in form are not only important for cosmesis but also for improving psychosocial attitudes and perceptions, and minimizing teasing. Reconstruction aims to approximate normal size, shape, and symmetry by surgically removing synostotic bone, reconstructing the cranio-orbital asymmetries, overcorrecting when necessary, and stabilizing the reconstructed skull while minimizing immediate postoperative and/or late complications.




Preoperative planning and preparation


Physical examination is equally important in evaluating the head from all sides and from above, noting any head tilt and any associated maxillofacial, orbital, dental, or auricular asymmetries or abnormalities ( Fig. 15 ).




Fig. 15


A 6-year-old child with Pruzansky type III craniofacial microsomia, demonstrating occlusal cant, hypoplastic mandible, and grade III microtia with canal atresia.


Several investigators have described using normative CAD-CAM templates to design fronto-orbital bandeaus and presurgical cutting guides, noting shorter intraoperative times and excellent immediate postoperative shape. The authors question long-term outcomes on such templates, as overcorrecting ( Fig. 16 ) is frequently needed for longer-lasting results.


Aug 26, 2017 | Posted by in General Surgery | Comments Off on Craniofacial Anomalies
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