Evaluation of Intraoperative Inferior Alveolar Nerve Exposure During and Postoperative Neurosensory Disturbances after Bilateral Sagittal Split Osteotomy: A Prospective Cross-sectional Study in Iran

Introduction: Inferior Alveolar Nerve (IAN) exposure and neurosensory disturbances (NSDs) following bilateral sagittal split osteotomy (BSSO) of the mandible are paramount. We aimed to assess intraoperative IAN exposure during and NSDs after BSOO surgery using different clinical assessment methods in a prospective study in a local setting. Materials and methods: The present study was a prospective cross-sectional study. We monitored the nerve exposure status during the BSSO. Our time points were: before surgery, one day after, one month later, three months after and six months after the BSSO surgery. We performed two-point discrimination test, static light touch test and pinprick test on both mental regions of the cases. Results: We included seven women and eight men. The average age of the participants was 25.13 ± 3.27 years. The results of the two-point discrimination test showed the following: the day after the BSSO compared to before the surgery, the sensation is significantly impaired in both mental regions. In addition, it is noted that during our study, the two-point discrimination test results showed a gradient healing, though not reaching the point before the surgery (P>0.05). The results of the Pinprick test also showed a gradual resolution of the NSDs; however, a significant sensation difference remained between six months after the BSSO and before the surgery. Conclusion: The BSSO surgery significantly impairs the IAN sensation, causing intraoperative IAN exposure and postoperative NSDs for the patients. A gradient resolution of the NSDs was observed in all the cases, though; the sensation of the mental region did not reach the pre-surgical levels.