Efficacy of distraction osteogenesis for mandibular reconstruction in previously irradiated areas: clinical experiences.

The efficacy of distraction osteogenesis in an irradiated area is controversial, although this procedure is now widely used in the field of craniomaxillofacial surgery. We report the clinical results from 4 patients with mandibular defects treated by lengthening of the irradiated mandibles. All patients had a mandibular defect caused by ablation of a malignant tumor. They had undergone radiotherapy at a total dose of 30 to 50 Gy to the surgical site after tumorectomy. Distraction osteogenesis was used as the secondary reconstruction method in 6 sites of the remaining irradiated mandibles and in 1 site of the transferred vascularized scapula after radiotherapy. The transported segment was obtained by corticotomy with an initial gap of 0 to 2 mm, and internal extension plates were used. Distraction was commenced after a latency period of 7 to 10 days and performed at the rate of 0.25 to 1.0 mm/d. The total amount of distraction and consolidation periods ranged from 15 to 25 mm and 120 to 193 days, respectively. In 5 of the 6 sites in the remaining irradiated mandibles, satisfactory bone formation in the distraction gap was observed, although a fracture after new bone formation was observed in 1 site. Fibrous callus formation was observed in 1 irradiated site only, and satisfactory results were obtained in another site of transferred vascularized scapula in the same patient. From these experiences, we believe that distraction may provide a reconstruction option for mandibular defects even under irradiated conditions because the procedure is simple and less invasive.