S2-11 SESSION 2: POSTERIOR VAULT DISTRACTION ENDOSCOPIC SPRING-MEDIATED DISTRACTION FOR UNILAMBDOID CRANIOSYNOSTOSIS

Abstract

Introduction: Implantable springs were first described in craniofacial surgery in 1997. The springs were designed to remodel the calvarium following release of a prematurely fused suture in craniosynostosis. Open surgical repair of lambdoid synostosis with spring-mediated distraction has subsequently been described. In other parts of the calvarium, endoscopic placement of springs has been successful. To our knowledge, no cases have been reported using an endoscopic approach with springs for unilambdoid craniosynostosis. We aim to describe our technique and demonstrate outcomes in the successful use of endoscopically placed distraction springs for unilambdoid synostosis. Methods: We performed a retrospective analysis of our series of endoscopic unilambdoid synostosis repairs. Cases were analyzed based on patient characteristics, operative details, and outcomes. The operation commences by approaching the lambdoid suture endoscopically. A suturectomy is performed and burr holes are placed on either side of the suture, perpendicular to the suturectomy. The springs are bent preoperatively to a predetermined force. Two springs are placed across the suturectomy defect and the skin is closed. The patient is monitored for improvement in head shape and cranial x-rays are performed to measure the degree of distraction. Results: Seven patients underwent endoscopic spring-mediated distraction for unilambdoid craniosynostosis. Six patients had the springs removed and one is scheduled for spring removal at a future date. The average age at the time of operation was 9.4 months (range: 3.9 - 11.0). The average force of each spring placed was 7.1 Newtons (range: 5.5 – 8.0). The average length of hospital stay after spring placement was 1.9 days (range: 1–2). The average duration between spring placement and removal was 5.6 months (range: 4.5 - 6.6). Four patients had x-rays immediately after placement and prior to removal. Each spring expanded an average distance of 15.3 mm (range: 3 - 25.3). There were no surgical complications. One patient had both preoperative and postoperative CT scans available. The angle of the cranial base, calculated by comparing foramen magnum to cribriform plate angles, improved 6.7 degrees (13.7 preoperatively to 7 postoperatively). Topographical scans were available for 3 patients. These all demonstrated improvements in head shape. Conclusion: Endoscopic spring-mediated distraction is a safe and effective treatment of unilambdoid craniosynostosis. The series represents the largest experience with this technique. Our approach could be considered in all cases of unilambdoid synostosis given the efficacious improvement in vault remodeling, low patient morbidity, short operating time, and minimal inpatient stay.