Intracranial volume (ICV) in isolated sagittal craniosynostosis: a retrospective case-matched-control study.

PURPOSE: Children with sagittal craniosynostosis (SC) are at risk of developing raised intracranial pressure (ICP). This is thought to result from cephalocranial disproportion-the restriction of normal cerebral development by a small cranial vault. It remains unclear whether intracranial volume (ICV) is altered in SC. This study offers a novel volumetric analysis of the scaphocephalic skull, comparing supratentorial (ST) volume, infratentorial (IT) volume, and total ICV of patients with sagittal synostosis to normal controls.

METHODS: ICVs of 32 consecutive patients undergoing total calvarial vault remodelling (TCVR) for isolated SC were compared to 32 age- and sex-matched normal controls. ICV was measured with manual techniques on head computerised tomographic (CT) scans using OsiriX software. A paired t test was used to compare data between cases and controls.

RESULTS: Mean total ICV, ST volume and IT volume were larger in SC than in controls, except in females > 6 months of age. There was no statistical significance. Regression analysis demonstrated larger ICVs in diseased children than in controls younger than 10 months, at which age trend lines intersected and the reverse became true for older children. This likely represents an evolving risk of cephalocranial disproportion beyond 10 months of age. The IT/ST volume ratio was conserved in scaphocephaly, and very closely approximated that of controls.

CONCLUSIONS: Sagittal craniosynostosis appears to be associated with a larger cranial vault at less than 10 months and a smaller vault at greater than 10 months, although statistical significance was not achieved.