The amount of soft tissue change to hard tissue movement following le fort ii osteotomy

Kim, Myung Jin; Yi, An Na

Abstract

Le fort II osteotomy is much useful technique to correct the midfacial hypoplasia including nasomaxillary complex especilly in the patient with dish face appearance. Not in simple orthognathic surgery but in Le Fort II osteotomy, the standardization of prognostic value is essential in treatment planning to achieve satisfactory postoperative results. According to previous reports, the ratio of soft tissue change to hard tissue movements varies as to different surgical methods and different facial regions. But there are few report about the ratio of soft tissue change to hart tissue movement following Le Fort II osteotomy. So we tried to develop standarized soft tissue surgical treatment objective. We have followed up 16 patients, who had received Le Fort II osteotomy by one operator from 1990 to 1996, one year postoperatively. In cephalometrics, we used Frankfort line as horizontal reference line, and vertical reference line as one drawn from Sella to horizontal line perpendicularly. The landmarks are G to soft tissue G, N on reference line to soft tissue N, ANS to Pn and A to Sn. The results are as follows. 1. The value of soft tissue change to hard tissue movement showed positive correlation, having statistical significancy at G, N2, N3 point. 2. At G, N2, N3 point, the ratio of soft tissue change to hard tissue movement was 0.51, 0.98 and 0.80 respectively and showed statistical significancy, while at N1, ANS, A point, that was 0.72, 0.49 and 0.26 but didn't showed statistical significance. 3. This result shows much the same change of the soft tissue change to hard tissue movement on the upper nasomaxilla, and less the same change on the lower maxilla and so the Le Fort II osteotomy can be recommended as a reliable effective operation method for correction of nasomaxillary retrusion.