Skeletal stability of Le Fort I osteotomy in patients with unilateral cleft lip and palate.

The skeletal stability of Le Fort I osteotomy was evaluated cephalometrically in 40 consecutive patients with unilateral cleft lip and palate (UCLP) (27 male and 13 female) who were operated on between 1987-1995. Their mean age at the time of operation was 23.7 years (range 16.3-40.4). The one-piece Le Fort I osteotomy was fixed with titanium plates and the osteotomy line was bone-grafted. Neither intermaxillary fixation nor occlusal splints were used postoperatively. Skeletal stability was analysed both horizontally and vertically on cephalograms taken shortly before operation, immediately afterwards, and at six months and at one year postoperatively. The mean maxillary advancement (point A) during the Le Fort I was 3.9 mm (range 0-8.9) and mean vertical lengthening 4.5 mm (range -0.6-10.5). One year postoperatively the mean maxillary horizontal relapse was 20.5% (0.8 mm, range 0-3.7) whereas the mean vertical relapse was 22.2% (1 mm, range 0-5.7). The vertical relapse reduced from 38% to 8.3% between 1987 and 1995, and there was a positive correlation between the amount of maxillary advancement and relapse both horizontally and vertically.