Quantitative Analysis of Change in Intracranial Volume After Posterior Cranial Vault Distraction

Posterior cranial vault distraction is considered to be more effective for increasing intracranial volume than fronto-orbital advancement or anterior cranial vault expansion, but the changes in intracranial volumes after posterior cranial vault distraction remain unclear. The changes in intracranial volume were investigated in patients of premature craniosynostosis treated by this technique. Seven patients, 3 boys and 4 girls aged from 5 months to 3 years 3 months (mean 23 months) at operation, with craniosynostosis underwent posterior cranial vault distraction at Juntendo University Hospital from 2011 to 2014. Patient characteristics, length of distraction, and pre- and postoperative computed tomography findings were reviewed. Total intracranial volume, including the supratentorial space and posterior cranial fossa, was measured using the workstation functions on three-dimensional computed tomography scans. Posterior distraction was performed without severe complications except in 2 patients requiring additional surgeries. The distraction length was 22.3 to 39 mm (mean 31 mm), the intracranial volume change was 144 to 281 mL (mean 192 mL), and the enlargement ratio of intracranial volume was 113% to 134% (mean 121%). The present quantitative analysis of intracranial volume change after posterior distraction showed greater increases in intracranial volume compared with previous reports. Furthermore, intracranial volumes in our patients became nearly normal and were maintained for the follow-up period (maximum 13 months). Posterior cranial vault distraction is very effective to increase cranial volume, so may be the first choice of treatment in patients of craniosynostosis.