LONG-TERM SKELETAL STABILITY AFTER RIGID FIXATION OF LE-FORT-L OSTEOTOMIES WITH ADVANCEMENTS

The purpose of this retrospective study was to evaluate relapse, compa ring large and small maxillary advancements with four-plate rigid fixa tion and without bone grafting. All patients had obstructive sleep apn ea, and underwent bimaxillary surgery. Standardized cephalometric anal ysis by two separate examiners was performed on serial radiographs of 20 patients immediately before surgery, and at 1 week and at least 6 m onths postoperatively (mean 18.5 months). The group was divided into t hree subsets to determine whether the magnitude of maxillary advanceme nt correlated with the magnitude of relapse. In group 1 (less-than-or- equal-to 6 mm, n = 4), the average advancement was 4.7 +/- 0.8 mm, wit h a mean relapse of 0 +/- 0.6 mm. In group 2 (7-9 mm, n = 9), the aver age advancement was 8.2 mm +/- 0.9, with a mean relapse of 0.7 +/- 1.5 mm. In group 3 (greater-than-or-equal-to 10 mm, n = 7), the mean adva ncement was 12.3 +/- 2.8 mm, with a mean relapse of 1.9 +/- 1.8 mm. Th ere was no statistical difference in the measured relapse among the gr oups.