# Craniosynostosis: OMFS Role in Craniofacial Team Management

## Introduction

Craniosynostosis is the premature fusion of one or more cranial vault sutures, affecting approximately 1 in 2,000 to 2,500 live births. It results in characteristic skull deformities, and when left untreated, can cause elevated intracranial pressure, visual impairment, and developmental delay. The OMFS surgeon plays an integral role on the craniofacial team, particularly in addressing associated midface hypoplasia, malocclusion, and obstructive airway pathology.

## Anatomy and Physiology

### Cranial Sutures

The metopic suture lies between the frontal bones and normally fuses by age 2. The sagittal suture between the parietal bones is the longest cranial suture. The coronal sutures lie between the frontal and parietal bones bilaterally. The lambdoid sutures lie between the parietal and occipital bones bilaterally. The squamosal sutures lie between the temporal and parietal bones. Sutures function as growth centers, with bone deposited perpendicular to the suture.

### Virchow's Law

Virchow's Law states that growth is restricted perpendicular to the fused suture while compensatory growth occurs parallel to the fused suture. This principle predicts the resulting skull morphology for each suture involved.

## Classification

### Non-Syndromic Craniosynostosis (70-85%)

| Suture | Frequency | Skull Shape | Key Features |
|---|---|---|---|
| Sagittal | 40-55% | Scaphocephaly (long, narrow) | Most common; dolichocephaly |
| Coronal (unilateral) | 20-25% | Anterior plagiocephaly | Ipsilateral flattening, contralateral bossing |
| Coronal (bilateral) | — | Brachycephaly | Short, wide skull |
| Metopic | 10-15% | Trigonocephaly | Triangular forehead, midline ridge, hypotelorism |
| Lambdoid | 1-3% | Posterior plagiocephaly | Rare; distinguish from positional |

Sagittal synostosis (scaphocephaly) is the most common type, accounting for 40 to 55% of cases, and produces an elongated, narrow skull (dolichocephaly). Coronal synostosis (anterior plagiocephaly) presents with unilateral ipsilateral forehead flattening and contralateral bossing when unilateral, or brachycephaly when bilateral. Metopic synostosis (trigonocephaly) produces a triangular forehead with a midline ridge and hypotelorism. Lambdoid synostosis (posterior plagiocephaly) is rare (1-3%) and must be distinguished from positional plagiocephaly.

### Syndromic Craniosynostosis (15-30%)

Crouzon syndrome features bicoronal synostosis, midface hypoplasia, exorbitism, and normal extremities, caused by an FGFR2 mutation. Apert syndrome features bicoronal synostosis, severe midface hypoplasia, and syndactyly of hands and feet, also caused by an FGFR2 mutation. Pfeiffer syndrome is characterized by broad thumbs and great toes with variable craniosynostosis, caused by FGFR1 or FGFR2 mutations. Muenke syndrome presents with coronal synostosis and hearing loss, caused by an FGFR3 P250R mutation. Saethre-Chotzen syndrome features coronal synostosis, ptosis, and a low frontal hairline, caused by a TWIST1 mutation.

![Illustration showing characteristic skull shapes resulting from premature fusion of each cranial suture](images/craniosynostosis-skull-shapes.jpg)

## Diagnosis

### Clinical Evaluation

The evaluation includes head shape assessment and cranial index measurement (CI = biparietal width divided by AP length multiplied by 100), palpation of suture ridging, anterior fontanelle patency assessment, ophthalmologic examination for papilledema (raised ICP), and assessment for syndromic features including extremities, facial structure, and hearing.

### Imaging

CT with 3D reconstruction is the gold standard for confirming suture fusion and surgical planning. Cranial ultrasound is useful in neonates when the fontanelle is open. MRI evaluates brain parenchyma, Chiari malformation, and hydrocephalus in syndromic cases. Radiation exposure should be minimized using low-dose CT protocols in pediatric patients.

### Differential Diagnosis

Positional plagiocephaly (deformational) is the most common cause of asymmetric head shape and involves no suture fusion. The ear is displaced anteriorly (versus posteriorly in lambdoid synostosis), and the head has a parallelogram shape. It is distinguished from craniosynostosis by clinical exam and imaging.

## Surgical Management

### Timing

Surgery is typically performed between 3 and 12 months of age for non-syndromic cases. Earlier intervention (3-6 months) allows for spring-mediated or endoscopic approaches, while later intervention (6-12 months) typically involves open cranial vault remodeling.

### Surgical Approaches

#### Endoscopic Strip Craniectomy

This minimally invasive approach is performed at 2 to 4 months of age. The suture strip is removed endoscopically, followed by postoperative helmet therapy for 6 to 12 months. It offers reduced blood loss, shorter hospital stay, and lower morbidity. It is best suited for sagittal and metopic synostosis.

#### Open Cranial Vault Remodeling

Fronto-orbital advancement (FOA) is the standard for coronal and metopic synostosis. It involves bifrontal craniotomy with orbital bar advancement and reshaping and is performed collaboratively between neurosurgery and OMFS or plastic surgery. Pi plasty and posterior cranial vault distraction are options for sagittal synostosis.

#### Posterior Cranial Vault Distraction

This growing technique is used for sagittal and multisutural synostosis. Internal distractors are placed posteriorly for gradual expansion over weeks. It increases cranial volume and reduces ICP.

### Midface Surgery (OMFS Domain)

Syndromic craniosynostosis patients frequently develop severe midface hypoplasia. Le Fort III osteotomy advances the midface as a monoblock from the cranial base, improving exorbitism, nasal projection, and the airway. Le Fort III distraction provides gradual advancement of the midface and is preferred for large advancements. Monobloc frontofacial advancement combines FOA and Le Fort III to address both the forehead and midface simultaneously but has a higher complication rate. Le Fort I osteotomy addresses isolated maxillary hypoplasia and may be combined with Le Fort III. Le Fort III is typically performed at 6 to 10 years of age, while Le Fort I is performed at skeletal maturity.

![Pre- and post-operative 3D CT reconstructions showing Le Fort III midface advancement in a patient with Crouzon syndrome](images/lefort-iii-craniosynostosis.jpg)

## The OMFS Role on the Craniofacial Team

The OMFS surgeon performs midface advancement surgery (Le Fort I, Le Fort III, monobloc distraction), orthognathic surgery for definitive skeletal correction at maturity, airway management (tracheostomy, mandibular distraction for airway obstruction), and distraction osteogenesis (mandibular and midface). The surgeon coordinates dental and occlusal management with the orthodontist and provides dentoalveolar surgery including extractions, management of impacted teeth, and implant rehabilitation. Longitudinal follow-up from infancy through adulthood is essential.

## Complications

Elevated ICP may persist or recur and requires monitoring with fundoscopy. Reoperation is needed in 15 to 20% of patients for secondary cranial or midface surgery. CSF leak and meningitis are risks with intracranial approaches. Blood loss during cranial vault procedures carries significant risk in infants. Hardware exposure or infection occurs, and resorbable plates reduce long-term foreign body complications. Early surgery may affect subsequent cranial and facial growth. Dural tears require careful technique during craniotomy and osteotomy.

![Flowchart showing the multidisciplinary management timeline for syndromic craniosynostosis from birth through skeletal maturity](images/craniosynostosis-management-timeline.jpg)

## Clinical Pearls

Positional plagiocephaly is far more common than lambdoid craniosynostosis, and the two should be distinguished by clinical features and imaging before referral for surgery. Syndromic patients require lifelong craniofacial team follow-up, with the OMFS surgeon addressing midface, occlusal, and airway needs. Le Fort III distraction is preferred over single-stage advancement for large midface movements in syndromic patients. FGFR mutations underlie most syndromic craniosynostoses, and genetic testing guides prognosis and family counseling. Elevated intracranial pressure should always be assessed, especially in multisutural and syndromic cases.

## References

1. Johnson D, Wilkie AOM. "Craniosynostosis." *European Journal of Human Genetics*. 2011;19(4):369-376.
2. McCarthy JG, et al. "Craniofacial Surgery for Craniosynostosis." In: Miloro M, et al., eds. *Peterson's Principles of Oral and Maxillofacial Surgery*. 4th ed. Springer; 2022.
3. Fearon JA. "Evidence-Based Medicine: Craniosynostosis." *Plastic and Reconstructive Surgery*. 2014;133(5):1261-1275.
4. Mathijssen IMJ. "Guideline for Care of Patients with the Diagnoses of Craniosynostosis." *Journal of Craniofacial Surgery*. 2015;26(6):1735-1807.