Recovery pattern of mandibular movement by active physical therapy after bilateral transoral vertical ramus osteotomy

Purpose: The purpose of the present study was to evaluate the effect of an active physical therapy (PT) protocol after transoral vertical ramus osteotomy and to investigate the rehabilitation patterns of mandibular movement. Materials and Methods: The study included 187 patients diagnosed with mandibular prognathism with or without facial asymmetry who had undergone bilateral transoral vertical ramus osteotomy from 2001 to 2009. The subjects were evaluated preoperatively and 1, 3, 6, 12, 18, and 24 months postoperatively in terms of the periods of PT and range of mandibular movement. The data were analyzed using 1-way analysis of variance (significance level, P <.05). Results: Of the 187 patients, 108 (57.8%) did not receive repeat intermaxillary fixation (IMF) during the PT period, 58 (31.0%) received it once, 15 (8.0%) twice, and 6 patients more than 3 times. The average PT period for all was 10.9 days (range 5 to 45). The mean maximal mouth opening was 50.7 mm before surgery, decreasing to 33.9 mm at 1 month postoperatively. This was followed by an increase to 46.3 mm at 6 months postoperatively, with the maximal mouth opening thereafter showing 93.9% to 95.7% recovery compared with the preoperative state. Conclusions: About 88% of the patients with transoral vertical ramus osteotomy responded well to the reduced IMF duration and active PT protocols, receiving repeat IMF less than twice. It required about 6 months to recover 90% of the preoperative maximal mouth opening and 12 months to recover near preoperative levels statistically. The benefits of reduced IMF duration and the PT protocols seem to promote rehabilitation of the masticatory muscles and prevention of mandibular hypomobility.