Osteodistraction of Midface Using Rigid External Distraction Device

ABSTRACT

We treated a total of 4 patients with midfacial hypoplasia, aged 12 to 19 years, using distraction osteogenesis between January 1998 and June 1999. In 3 patients with severe maxillary hypoplasia, we used rigid external distraction device developed by Dr. Polley. The distraction was performed from 5 days after Le Fort I osteotomy at a rate of 1 mm/day for 10 to 15 days. After distraction was completed, the device was left in place for another 6 weeks for bony consolidation. And then, an orthodontic face mask was used with elastic traction for 2 months. In one patient with partial hypoplasia of the midface, the osteotomized zygoma and a part of the maxilla was distracted selectively using rigid external distraction device a total of 15 mm. In the degree of SNA, mean value improved from 75.0(75.5, 75.0, 74.5) to 81.8(81.5, 83.0, 81.0) after 6 months later. In relapse rate, distracted length decreased from 10 mm to 6 mm, 15 mm to 8 mm, 13mm to 7 mm at 6 months later resulting in relapse rate of 44.3%. The follow-up period was from 7 to 26 months. Advantages of rigid external distraction device are highly effective technique of maxillary distraction, easy control of vector of distraction and no additional surgical procedure for removal of the device. In conclusion, the external distraction device is very useful for midface distraction.