Le Fort I maxillary osteotomies in cleft palate cases. Surgical changes and stability.

Surgical and postsurgical changes in maxillary position following transpalatal osteotomy at the le Fort I level in 30 patients with clefts of lip and palate were evaluated cephalometrically. By superimposing on natural reference structures, a more accurate and detailed evaluation of change in maxillary position was possible than by using conventional cephalometric analyses. The mean horizontal advancement was 9 mm, with a mean vertical change of 3 mm. While it is customary to express postsurgical relapse as a percentage of surgical change (in this case 7% mean horizontal relapse and 23% mean vertical relapse), the most remarkable finding to emerge from this study was the variability in surgical and postsurgical change which would be obscured by concentrating on descriptive statistics. Postsurgical change was related to the amount of surgical change, but the correlation coefficients are quite low, and so other factors must be responsible for a significant proportion of any relapse.