Effect of bone quality and position of the inferior alveolar nerve canal in continuous, long-term, neurosensory disturbance after sagittal split ramus osteotomy

Objectives: To examine the relationship between the anatomical position and the bone quality of the inferior alveolar nerve (IFAN) canal and long-term neurosensory disturbance (NSD) of the IFAN after a sagittal split ramus osteotomy (SSRO). Material and methods: CT images were taken of patients with mandibular prognathism. The location of the IFAN and the bone density around the IFAN were measured on CT images. Whether NSD at 6 months and 1 year after SSRO was related to the position and bone quality of the IFAN canal was analyzed. Results: Significant correlations were found between the anatomical position and the bone quality of the IFAN canal and the period to the resolution of NSD of the IFAN from 3 months to 1 year after SSRO. If the HU values around the IFAN were greater than 300 HU and/or the distance from the buccal aspect of the IFAN canal to the outer buccal cortical margin was less than 6 mm, NSD of the IFAN at 1 year after SSRO was significantly increased. Conclusion: It is important to pay particular attention to the anatomical position of the IFAN and the bone quality around the IFAN to predict long-term NSD of the IFAN after SSRO. (C) 2011 European Association for Cranio-Maxillo-Facial Surgery.