Is the magnitude of mandibular movement a risk factor for inferior alveolar nerve neurosensory disturbance after bilateral sagittal split osteotomy?

Aim To investigate the effect of the magnitude of mandibular movement during bilateral sagittal split osteotomy (BSSO) on the incidence of inferior alveolar nerve neurosensory disturbance (NSD). Patients and methods The present cohort study included patients presented to the Maxillofacial Unit, General Surgery Department, Assiut University Hospital, Egypt. All patients underwent BSSO to correct class II malocclusion. Patients were divided into two groups; the first group included patients with mandibular movement less than 7mm, and the second group included patients with mandibular movement more than 7mm. Then, we investigated the incidence of NSD in both groups. Results The study included 32 patients (64 sides). The first group included 24 patients (48 sides), and the second group included eight patients (16 sides). The incidence of permanent NSD that lasted for more than 1 year in all patients was 9.375%. The incidence among the first group was 4.166%, whereas among the second group was 25%. A statistically significant difference is present between them, with P value of 0.013. Conclusion Magnitude of mandibular movement more than 7mm during BSSO is considered to be a risk factor for inferior alveolar nerve NSD.