New-onset craniosynostosis after posterior vault distraction osteogenesis.

The aims of this study were to document the incidence of new-onset craniosynostosis (NOC) after posterior vault distraction osteogenesis (PVDO), to determine risk factors for the development of NOC, and to deduce the cranial ramifications of NOC. An institutional review board-approved retrospective review of all patients who underwent PVDO at the Children's Hospital of Philadelphia was performed. Demographics, perioperative data, as well as preoperative and postoperative three-dimensional computed tomographic scans were analyzed. Suture patency preoperatively and postoperatively was recorded.Thirty patients underwent PVDO for suspected increased intracranial pressure and/or severe turribrachicephaly from 2008 to 2013. Twenty-four patients had syndromic diagnoses. The average age at the time of PVDO was 2.03 years. Distraction distances ranged from 19 to 40 mm, with an average of 28.7 mm. Among the 19 patients who had patent lambdoid sutures before PVDO, new-onset lambdoid fusion was seen in 17 patients after PVDO (89.5%), whereas the suture remained open in 2 patients (10.5%). New-onset lambdoid fusion was not significantly associated with age at distraction (P = 0.28), sex (P = 0.47), length of distraction (P = 0.93), or diagnosis (P = 0.61). Similarly, new-onset sagittal synostosis was not associated with age at distraction (P = 0.06), sex (P = 0.64), length of distraction (P = 0.83), or diagnosis (P = 0.25). None of the patients who developed NOC had characteristic head shape changes such as mastoid bulges or scaphocephaly. New-onset lambdoid and sagittal synostoses occur frequently after PVDO. Although the diagnosis of NOC is obvious radiographically, the clinical importance of the diagnosis morphometrically, neurodevelopmentally, and in cranial growth has yet to be fully investigated.