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

PURPOSE: 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.

METHODS: This was a prospective, split-mouth study of skeletally mature patients undergoing BSSO. Patients were included as study subjects if they underwent BSSO for mandibular advancement > 10 mm and, following the splits, the IAN was freely entering the distal segment (IANDI) on one side and within the proximal segment (IANPR) on the other. Descriptive, bivariate, and Kaplan-Meier statistics were computed.

RESULTS: The study sample included 13 subjects (8 female, 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 FSR bilaterally within 1 year of surgery. There was no difference in the median times to FSR based upon the location of the IAN (IANDI = 105 days vs IANPR = 126 days, p = 0.57).

CONCLUSION: In SSO for mandibular advancement with movements > 10 mm, leaving the IAN within the proximal segment may not impact time to FSR.