Incidence of inferior alveolar nerve sensory deficit and intra-operative nerve encounters after advancement of retrognathic mandible – A cross-sectional survey study

Aims and Objectives: The aim of the current cross?sectional study was to conduct a survey among the oral and maxillofacial surgeons of South India regarding their experiences of incidence of inferior alveolar nerve (IAN) neurosensory deficit after bilateral sagittal split osteotomy (BSSO) for correction of mandibular retrognathism and to assess the intra?operative nerve encounters and its effect on the inferior alveolar neurosensory deficit (NSD), 6 months post?operatively. Materials and Methods: A self?administered questionnaire (SAQ) was prepared using Google Forms (Google Inc.) and sent to the prospective participants through various social media outlets such as Facebook, WhatsApp groups etc., of the maxillofacial surgery specialty for a period of 3 months. SAQ from surgeons with more than 5 years of experience in orthognathic surgery were included. Results: The incidence of NSD post?BSSO advancement surgery from 859 cases after 6 months was 15.1% (130). After splitting the mandible, the IAN was seen in the proximal fragment in 472 sites and needed dissection. The nerve was transected and neurorrhaphy was carried out in 26 sites. A Chi?square test was used to analyse the qualitative variables. The IAN was not visible post?osteotomy in 140 sites and in the distal fragment in 1080 sites. These groups had decreased incidence of NSD. The NSD was significantly higher in cases where the nerve was transected and sutured, P value <0.001 as compared with the other nerve status, followed by the nerve in the proximal fragment needing dissection. Conclusion: The IAN status intra?operatively can be assumed to have a significant role in persisting NSD

Preliminary study on histologic changes in the nerve and surrounding tissues after inferior alveolar nerve transposition in rabbits

PURPOSE: The purpose of this study was 1) to find nerve damage after inferior alveolar nerve transposition and 2) to examine whether the soft tissue or bone changes around the nerve produce the compression to the nerve in the healing period. MATERIALS AND METHOD: Inferior alveolar nerve was exposed through the bony window and the scratch was made in the bone to be thought as the inferior alveolar canal. Suture was made after the nerve was repositioned. The nerve and surrounding tissues were examined with the light microscope and the fluorescent microscope before surgery and at 1 month, 3 months, and 5 months after surgery. RESULTS: After surgery, the epineurium was damaged and the nerve was divided to several fascicles covered with the perineurium The newly formed fibrous connective tissue and vessels were seen around fascicles. There was new bone formation. However the nerve was not compressed by the connective tissue or the new bone. CONCLUSION: The results of this study suggest that neurosensory disturbances after inferior alveolar nerve transposition are resulted by the direct trauma in surgery rather than the compression to the nerve by the scar or new bone formation in the healing period.