DISTRACTION OSTEOGENESIS FOR RECONSTRUCTION OF MANDIBULAR SYMPHYSEAL DEFECTS

Objective: We investigated the feasibility of arced trifocal distracti on osteogenesis for reconstruction of mandibular symphyseal defects. D esign: Four adult canine subjects were used. An external apparatus was designed to allow trifocal distraction around an are. An anterior man dibulectomy was performed between the third premolars bilaterally. The bony defect was regenerated using trifocal distraction osteogenesis a t a rate of 1 mm a day bilaterally. New arced bone was produced over a period of 20 to 35 days. The apparatus functioned as an external fixa tor for the ensuing 6 weeks. The apparatus was then removed, the dogs were returned to their preoperative diet, and were killed after 2 week s of observation. Main Outcome Measures: Grossly a smooth arc of bone was formed measuring 4.5 to 5.5 cm in length, 2.2 to 3.0 cm in height, and 1.3 to 1.5 cm in width. Histologically all specimens demonstrated direct membranous bone growth. Radiographically opaque columns were s een streaming in the direction of distraction. Conclusions: Symphyseal bony defects resulting from oncologic resection, trauma, and congenit al deformities create tremendous cosmetic and functional handicaps and have remained extremely challenging to surgically reconstruct. This s tudy demonstrates the ability to use arced trifocal distraction osteog enesis to reconstruct anterior mandibulectomy defects in a canine mode l. This method may provide a satisfactory solution to a difficult prob lem in human mandibular reconstruction.