Treatment of temporomandibular joint ankylosis and facial asymmetry with bidirectional transport distraction osteogenesis technique.

Transport distraction technique is a good treatment modality for unilateral temporomandibular joint ankylosis. However, with a unidirectional distraction, it is not possible to correct facial asymmetry that results from mandibular hypoplasia associated with early-onset unilateral temporomandibular joint ankylosis. For this purpose, gap arthroplasty and simultaneous bidirectional transport distraction was used to correct these deformities. Although vertical distraction corrects vertical deficiency of the ramus and creates a neocondyle, the simultaneous anteroposterior distraction of the transport segment corrects facial asymmetry resulting from horizontal shortness of mandible. Three patients, whose mean mouth opening was 8.6 mm, were successfully treated with this technique. Mean advancements in vertical and anteroposterior direction were 14.7 and 7.7 mm, respectively. Mean maximal mouth opening was 29.7 mm postoperatively. The average follow-up period was 13 months (range, 12-15 mo). During this period, reankylosis was not observed, and the interincisal distance did not decrease. Gap arthroplasty and bidirectional transport distraction of the mandibular ramus is a good and effective therapeutic option in treatment.