Plate fixation of extra-oral subcondylar ramus osteotomy for correction of mandibular prognathism: clinical aspects and short term stability.

Aim: The present study describes an extra-oral approach for subcondylar oblique ramus osteotomy using stable fixation for setback of the mandible. The aim was to investigate the incidence of neurosensory disturbances of the mandibular nerve, evaluate facial scar appearance, and assess skeletal stability following the procedure.

Methods: Forty-two consecutive patients with mandibular prognathism were operated upon using the subcondylar oblique ramus osteotomy and plate fixation. The patients were followed up for 6 months following surgery. Intra-operative and postoperative complications, neurosensory function, and facial scar characteristics were recorded. Lateral cephalograms were available immediately before operation, and immediately after operation and 6 months postoperatively. Skeletal stability was based on cephalometric assessment.

Results: Among the 19 patients operated earliest, neurosensory disturbances were recorded in five individuals at the 6 month follow-up. In the subsequent group of 23 patients, no disturbances were reported. All but two patients were not concerned about the facial scar 6 months postoperatively. Mean anterior relapse at the 6 month follow-up was 0.5 mm, representing 9% of the surgical setback.

Conclusion: Extra-oral subcondylar oblique ramus osteotomy with plate fixation is a stable procedure with a low incidence of neurosensory disturbances if the osteotomy is placed well behind the mandibular foramen. Facial scar appearance was rarely a matter of concern to the patients.