Surgical implications of the anatomic situation of the mandibular canal for mandibular osteotomies: a cone beam computed tomographic study.

PURPOSE: In bilateral sagittal split osteotomy (BSSO), the risk of lesion of the inferior alveolar nerve (IAN) is important. The aim of this study was to investigate the situation of the IAN in the area of the BSSO in preoperative 158 CBCT.

METHODS

The situation of the mandibular canal (MC) has been studied in six coronal sections (one section each 4 mm) from the proximal root of the second mandibular molar. The height of the MC related to the height of the mandible, and the horizontal distance between the MC and the lateral cortical plate related to the mandibular width have been determined in each section. The cancellous bone width has been measured allowing to determine a cancellous bone ratio.

RESULTS

The variability of the MC was high, depending mainly on the cancellous bone ratio which was higher when the IAN was deep. When a third molar was present, the MC was lower in the area of the third molar.

CONCLUSIONS

To decrease the risk of injuring the IAN in BSSO, the evaluation of the cancellous bone ratio by a preoperative CBCT may be proposed to adapt the surgical technique to the anatomy.