Combined maxillary and mandibular distraction osteogenesis.

Mandibular elongation by gradual distraction in patients with hemifacial microsomia is a simple and effective procedure to correct facial asymmetry. The changes in mandibular dimension result in changes in dental occlusion. These are minimal in children because of the rapid growth of the maxilla and can be corrected easily with minor orthodontic treatment. Mandibular distraction in adults with hemifacial microsomia produces good aesthetic results but leaves the patient with a severe alteration in the occlusion requiring complex orthodontic treatment over a long period of time. To avoid this problem, an incomplete Le Fort I osteotomy is performed simultaneously with the mandibular corticotomy. Intermaxillary fixation is placed on the fifth postoperative day, and distraction is initiated. This technique preserves the preexisting stable occlusion. After distraction, both the maxillary and mandibular occlusal planes become horizontal, and facial asymmetry is corrected.