[Distraction osteogenesis in correction of mandibular micrognathia accompanying obstructive sleep apnea syndrome]

To evaluate the effect of distraction osteogenesis in correction of mandibular micrognathia accompanying obstructive sleep apnea syndrome (OSAS).

A total of 15 patients, aged 9 to 43 years, 11 males and 4 females, were treated. 7 patients suffered from bilateral ankylosis of temporo manclibular joint inducing severe mandibular micrognathia and accompanying severe OSAS. 3 cases suffered from unilateral TMJ ankylosis with OSAS. 3 patients suffered from congenital developmental micrognathia with OSAS. 2 cases were caused by trauma. Among the 15 patients, 12 were treated by synchronous bilateral mandibular distraction, 3 patients were distracted unilaterally. Every patient had been evaluated pre- and postoperatively with cephalometry and polysomnography.

The minimum distance of distraction was 9 mm, the maximum was 30 mm, with a mean of 20.4 mm, in mandible of 15 patients with 27 sides. The distraction process was smooth in all the cases. The osteogenesis was good, without infection and other complications. Complete curative effect was achieved in 4 severe, 3 moderate, and 4 mild cases. The posterior airway space was increased from averaged 4.5 mm preoperatively to 12.4 mm. The increase of SNB angle was from preoperative 66 degrees to 75 degrees on average postoperatively. The vast majority of the patients had their subjective symptoms alleviated gradually or disappeared completely. The results were stable without relapse during a follow-up period of 12 months.

The distraction osteogenesis can not only be used to effectively correct severe mandibular micrognathia deformity, but also can cure its accompanying OSAS. The procedure is simple, with low risk, high curative rate, low relapse rate, and stable result. Up to now, it is the most effective method in the treatment of this difficult and complicated kind of disorder.