Combined metopic and sagittal craniosynostosis: is it worse than sagittal synostosis alone?

OBJECT Combined metopic and sagittal craniosynostosis is a common variant of the nonsyndromic, multiplesuture synostoses. It is unknown whether this combined form causes reduced intracranial volume (ICV) and potentially more brain dysfunction than sagittal synostosis alone. This study is a volumetric comparison of these 2 forms of craniosynostosis. METHODS The authors conducted a retrospective chart and CT review of 36 cases of isolated sagittal synostosis or combined metopic and sagittal synostosis, involving patients seen between 1998 and 2006. Values were obtained for the intracranial compartment, brain tissue, CSF space, and ventricular volumes. Patients with craniosynostosis were then compared on these measures to 39 age- and sex-matched controls. RESULTS In patients with isolated sagittal synostosis and in those with combined metopic and sagittal synostosis, there was a trend toward smaller ICV than in controls (p < 0.1). In female patients older than 4.5 months of age, there was also a trend toward smaller ICV in patients with the combined form than in those with sagittal synostosis alone (p < 0.1), and the ICV of patients with the combined form was significantly smaller than the volume in controls in the same age group (p < 0.05). Brain tissue volume was significantly smaller in both patient groups than in controls (p < 0.05). Ventricular volume was significantly increased (compared with controls) only in the patients with isolated sagittal synostosis who were younger than 4.5 months of age (p < 0.05). Overall CSF space, however, was significantly larger in both patient groups in patients younger than 4.5 months of age (p < 0.05). CONCLUSIONS These findings raise concerns about intracranial and brain volume reduction in patients with sagittal and combined metopic and sagittal synostoses and the possibility that this volume reduction may be associated with brain dysfunction. Because the ICV reduction is greater in combined metopic and sagittal synostosis in patients older than 4.5 months of age than in sagittal synostosis in this age group, the potential for brain dysfunction may be particularly true for these younger infants.