Management of the Inferior Alveolar Nerve in Large Sagittal Split Advancements: To Free or Not?

Summary: The purpose of this study was to evaluate whether neurosensory recovery of the inferior alveolar nerve (IAN) is influenced by its location following sagittal split osteotomy (SSO) in patients undergoing large mandibular movements. This was a prospective, split-mouth study of skeletally mature patients undergoing bilateral SSO. Patients were included as study subjects if they underwent bilateral SSO for mandibular advancement greater than 10 mm and, following the splits, the IAN was freely entering the distal segment on one side and within the proximal segment on the other. Descriptive, bivariate, and Kaplan-Meier statistics were computed. The study sample included 13 subjects (eight female subjects; mean age, 18.7 ± 1.8 years) undergoing 26 SSOs. Eleven subjects underwent bimaxillary surgery; 10 had simultaneous genioplasty. The mean mandibular movement was 12.2 ± 1.4 mm and was not significantly different between sides ( P = 0.43). All subjects achieved functional sensory recovery (FSR) bilaterally within 1 year of surgery. There was no difference in the median times to FSR based on the location of the IAN (distal segment, 105 days, versus proximal segment, 126 days; P = 0.57). In SSO for mandibular advancement with movements greater than 10 mm, leaving the IAN within the proximal segment may not impact time to FSR.

Clinical Question/level Of Evidence: Risk, II.