A Modified Technique of Mandibular Ramus Sagittal Split Osteotomy for Prevention of Inferior Alveolar Nerve Injury: A Prospective Cohort Study and Outcome Assessment.

Abstract

Postoperative functional impairment of the inferior alveolar nerve (IAN) has been a common and well-recognized complication. Our study introduced a modified Obwegeser-Dal Pont bilateral sagittal split osteotomy (BSSO) technique and evaluated the subsequent incidence of postoperative neurosensory disturbance of IAN. In this prospective cohort study, 57 patients receiving our modified BSSO during orthognathic surgery were enrolled. The technique contained opening the 2 ramus cortices and inserting the osteotome bypassing the IAN to avoid nerve injury. A 5-point scale self-assessment questionnaire was used to evaluate IAN neurosensory disturbance one week, six months and 12 months postoperatively. Differences between groups were analyzed using χ test for categorical and Wilcoxon signed-rank test for pairwise categorical data. Complete ramus splitting could be achieved in 109 (95.6%) sides. Lower lip or chin neurosensory disturbances presented in 72 (63.2%) sides 1 week postoperatively and gradually reduced to 9 (7.9%), and 4 (3.5%) at postoperative months 6 and 12, respectively. This BSSO technique could be safely performed with low rates of IAN exposure and injury and a low incidence of persistent neurosensory disturbance in 3.5% of patients 12 months postoperatively.