Intra-Operative Nerve Encounters and Incidence of Inferior Alveolar Nerve Sensory Deficit after Bilateral Sagittal Split Osteotomy-A Pilot Study.

Introduction: Bilateral sagittal split osteotomy (BSSO) is the most performed orthognathic surgery for mandibular dentofacial abnormalities. The most common complication is the neurosensory deficit. The current study was aimed at determining the incidence of inferior alveolar nerve neurosensory deficit (NSD) following BSSO surgery, and in assessing intra-operative nerve encounter status and possible relation to NSD.

Materials And Methods: The pilot study was conducted in the Oral and maxillofacial surgery department, KIMS Dental college and hospital, Amalapuram, Andhra Pradesh. The sample of thirty subjects were selected from the patients undergoing BSSO surgeries from April 2022- July 2023, as according to the inclusion and exclusion criteria. Patients were followed up for six months postoperatively. The evaluation was done preoperatively and postoperatively (1week, 1 month, 3 months, 6months) using subjective and objective methods. NSD was assessed by both subjective (Five-point scale) and objective (2-point discrimination, pin pressure, and thermal discrimination) tests.

Statistical Analysis: Descriptive statistics were used.

Results: Post-osteotomy, the inferior alveolar nerve was in the distal fragment in 36 (60%) of the sites, 14 (22%) on the proximal fragment and needed dissection, 10 (18%) not seen post osteotomy, and nil (0%) got transected. The incidence of prolonged NSD was highest seen in the proximal fragment needing dissection. The neurosensory deficit after BSSO was 21.5% in post-six-month follow-up.

Conclusion: The incidence of transient neurosensory deficit of the inferior alveolar nerve after BSSO surgeries is inevitable. Prolonged NSD is due to nerve manipulation depending on the nerve status intra-operatively.