Two-stage maxillary distraction osteogenesis using a modified external device: clinical outcome and complications.

Rigid external distraction is currently used to correct severe maxillary hypoplasia. The purpose of this retrospective study was to present the clinical results and complications of a two-stage surgical approach using a modified external distraction system that consists of maxillary distraction and then maxillary fixation. We treated eight patients with cleft lip and palate in this way from 2016 to 2018. Lateral cephalograms taken before the first operation, after distraction, two weeks after the second operation, and one year after treatment were used to examine maxillofacial morphology. Velopharyngeal function was evaluated by a speech therapist. The mean movements of the maxilla forwards and downwards at Point A were 12.0mm and 8.0mm at the completion of distraction and those at Point B were 5.0mm backwards and 9.7mm downwards. Mouth opening was limited at this time, and was relieved after maxillary fixation. The mean relapse one year postoperatively was 24.3% horizontally and 52.5% vertically. Velopharyngeal function was unchanged by the operation. We conclude that the method has advantages that include the short duration of wearing distractors and increased acceptance by patients. The modified external device advanced the midface sufficiently.