Extraoral vs. intraoral distraction osteogenesis in the treatment of hemifacial microsomia.

During hemifacial microsomia (HMF), an important phase of the treatment is elongation of the hypoplastic mandible, mainly the ramus, at an early stage. Twenty-two patients with HFM were treated with distraction osteogenesis: 12 with an extraoral device (10 unidirectional and 2 multidirectional) and 10 with an intraoral device. The mean elongation with the extraoral device was 21 mm, and with the intraoral device was 17 mm, resulting in a more symmetrical facial appearance. The advantages and disadvantages of both methods are presented, based on the authors' experience and a review of the literature. The extraoral device permits elongation of a greater distance, enables extraoral control of the vector of elongation, and conserves the gonial angle by working in many directions. The main disadvantages of the extraoral device are the social inconvenience to the patient and the extraoral cutaneous scars. Conversely, the intraoral device is much more socially convenient to the patient and avoids residual scarring. However, in 2 patients treated with an intraoral device, an undesired contralateral open bite appeared as a result of reduced vector control. The intraoral method should always be considered first because of its previously mentioned advantages. However, in severely hypoplastic patients, when three-dimensional correction and gonial angle control are necessary, or when there is a limited space along the planned distracted bone, the extraoral device has an advantage over the intraoral device.