Cross-sectional tomography in evaluation of patients undergoing sagittal split osteotomy.

A study was performed to evaluate the possibility of locating the mandibular canal before sagittal split osteotomy by cross-sectional spiral tomography in 55 patients. Visibility of the whole canal wall circumference was excellent or good in 65.5% fair in 18.2%, and poor in 12.7% of cases. Only four canals (3.6%) were invisible. The canal was located lingually in 61 cases, buccally in 9 cases, and centrally in 34 cases. In patients with mandibular protrusion, the mean (+/- SD) buccolingual width was significantly smaller (9.5 +/- 1.51 mm vs 10.4 +/- 1.46 mm, P < .01) and the mandibular canal was more often buccally located than in patients with retrognathia.