J Chow1, U Hägg, H Tideman. 1. Department of Oral and Maxillofacial Surgery, University of Hong Kong.
Abstract
PURPOSE: This study evaluates the postsurgical stability of segmentalized Le Fort I osteotomies with miniplate fixation in patients with maxillary hypoplasia. MATERIALS AND METHODS: Eighteen adult patients who had undergone segmentalized Le Fort I osteotomy for anterior and inferior repositioning of their hypoplastic maxilla were studied radiographically. The positional change of five maxillary landmarks (PNS, ANS, A, U1, and UM) were measured on serial cephalometric radiographs according to a reference frame constructed by using the SN line for superimposition, sella as the origin of the coordinates, and a line parallel to Frankfort horizontal plane as the x-axis. The positional changes of all variables were measured twice, and the means were calculated for analysis. The paired t-test was used for statistical analysis. RESULTS: Statistically significant mean vertical change (P < .01) was found in the anterior maxilla, with U1 having moved up by 27.8% (1.5 mm) of its initial downward surgical movement by 1 year postoperatively. U1 and UM had moved forward 2.0 mm and 1.5 mm, respectively (P < .01) by 1 year postoperatively, but the bony landmarks had no statistically significant change in their horizontal positions. CONCLUSION: Although statistically significant postsurgical changes were found at 1 year postoperatively, overcorrection is not recommended because of the large individual variation observed and the relatively small magnitude of the relapse.
PURPOSE: This study evaluates the postsurgical stability of segmentalized Le Fort I osteotomies with miniplate fixation in patients with maxillary hypoplasia. MATERIALS AND METHODS: Eighteen adult patients who had undergone segmentalized Le Fort I osteotomy for anterior and inferior repositioning of their hypoplastic maxilla were studied radiographically. The positional change of five maxillary landmarks (PNS, ANS, A, U1, and UM) were measured on serial cephalometric radiographs according to a reference frame constructed by using the SN line for superimposition, sella as the origin of the coordinates, and a line parallel to Frankfort horizontal plane as the x-axis. The positional changes of all variables were measured twice, and the means were calculated for analysis. The paired t-test was used for statistical analysis. RESULTS: Statistically significant mean vertical change (P < .01) was found in the anterior maxilla, with U1 having moved up by 27.8% (1.5 mm) of its initial downward surgical movement by 1 year postoperatively. U1 and UM had moved forward 2.0 mm and 1.5 mm, respectively (P < .01) by 1 year postoperatively, but the bony landmarks had no statistically significant change in their horizontal positions. CONCLUSION: Although statistically significant postsurgical changes were found at 1 year postoperatively, overcorrection is not recommended because of the large individual variation observed and the relatively small magnitude of the relapse.