Alterations in Sphenoid Anatomy in Craniosynostosis: Implications for Fronto-Orbital Advancement.

ABSTRACT

OBJECTIVE: Fronto-orbital advancement involves removal of the fronto-orbital bandeau. Visualization of the saw blade is lost as it passes through the fronto-orbital-sphenoid junction (FOSJ), placing the temporal lobe at risk of injury. We aim to provide a 3D analysis of the space surrounding this osteotomy to differentiate various types of craniosynostoses. DESIGN: Retrospective cohort. SETTING: Institutional. PATIENTS Thirty patients with isolated unicoronal synostosis, nonsyndromic bicoronal synostosis, metopic synostosis, Apert syndrome, Crouzon syndrome, and Muenke syndrome. INTERVENTIONS: CT scans conducted between 2 months to 2 years of age were 3D reconstructed to compare craniometrics against normal controls. MAIN OUTCOME MEASURE(S) Craniometrics. RESULTS: The mean bone thickness of the FOSJ at the level of the supraorbital rim was significantly small for the Apert, unicoronal and bicoronal groups. The mean vertical height of the middle cranial fossa from the lesser sphenoid wing was significantly greater in the unicoronal group. The mean vertical height of the tip of the temporal lobe from the lateral sphenoid ridge was greater in the unicoronal, isolated bicoronal, and Apert groups. The mean corneal protrusion beyond the lateral orbital rim was significantly greater in the Apert and unicoronal groups. The mean horizontal depth of the orbit was smallest in the Apert group. The mean vertical distance between the dacryon and the foramen cecum, and the mean volume of temporal lobe beneath the sphenoid shelf were the largest in the Apert group. CONCLUSIONS: Patients with Apert syndrome have the most unfavorable morphology of the anterior and middle cranial fossae.