Success of Bone Ossification After Posterior Vault Distraction Osteogenesis in Patients With Craniosynostosis.

Background: Posterior vault distraction osteogenesis (PVDO) is an effective treatment for multisuture and syndromic craniosynostosis. It remains unclear how well the calvarium ossifies after PVDO, especially in older patients when they have plateaued in their cranial growth phase. The purpose of this study is to report outcomes associated with PVDO across a wide range of ages at our institution.

Methods: Operative details, distraction parameters, complications, and details of cranioplasty, if applicable, were obtained for all patients who underwent PVDO between March 2016 and July 2022. The surface areas of distraction sites and residual cranial defects were measured from computed tomography scans after a consolidation phase, and the percentages of the distraction regions with ossification were subsequently calculated.

Results: Fifteen patients underwent PVDO at a mean age of 5.1 years (0.5-18.7 y). The mean percentage of ossification among all patients was 80.4% (59.1%-95.3%). The degree of ossification was not significantly associated with age at the time of surgery at the univariate level (Pearson-r=-0.15, P=0.573). Three patients (20.0%) required titanium mesh cranioplasty for definitive reconstruction, which was significantly more likely in patients who were >4 years old at the time of PVDO (P=0.04).

Conclusions: Complete ossification of the distracted area of the cranium is unlikely after PVDO. Ossification appears less robust with increasing age, although not statistically significant in our study population, likely due to the limited sample size. Future studies should assess the role of age, latency period, and distraction rate in minimizing residual defects.