Advantages of Calvarial Vault Distraction for the Late Treatment of Cephalocranial Disproportion.

PURPOSE Cephalocranial disproportion is a symptomatic condition related to a volume discrepancy between the calvarial vault and the brain. Traditional expansion techniques are unfavorable in older children due to inadequate dural ossification, lack of bone pliability, and limited future growth potential. The authors review their experience using distraction to close bone defects in this setting. METHODS A retrospective analysis was performed of all patients treated using distraction in this setting by a single surgeon. Demographic and outcomes data were collected. The efficacy of ossification of bone defects after expansion by distraction was measured using volume analysis of three-dimensional computed tomography (CT) scans. This required a CT scan at the completion of device activation and a follow-up CT scan 6 months or more beyond activation. RESULTS Sixteen patients (17 distractions) met the imaging-based inclusion criteria. The average age at surgery was 3.97 (2.14-6.89) years. The mean initial bone defect volume after asymmetric transverse distraction was 7.26 (5.45-13.73) mL. The mean final defect volume was 2.18 (0.00-5.90) mL with a mean change of 5.08 (1.21-12.79) mL and mean interval time of 27.85 (7.13-56.39) months. This represents a mean percent defect closure of 72.30 (20.38-100.00). CONCLUSION Distraction osteogenesis is a very effective tool for treating the older child with cephalocranial disproportion. The ability to ossify the bone defects without a donor site provides a considerable advantage in these patients.