악교정 수술시 골편의 술전 예측치와 술후 실제치에 관한 연구

Study on the prepoperative prediction values and the postoperative actual values of the osteotomized segments in orthognathic surgery

It is of interest and also a responsibility of the operator to make a proper prognosis of the outcome of a surgery on maxillotacial deformity and perform retrospective studies of preoperative plans on the basis of postoperative results. In order to assess the accuracy of a planned surgery according to preoperative preparations and operative proceduures, 254 patients were followed-up who had visited the department ot oral and maxillofacial surgery at the Yonsei university for maxillfoacial deformity since 1990 to 1994 The deformites of the maxilla were treated with LeFort I osteotomy and those of the mandible with sagittal split ramus osteotomy or intraoral vertical ramus osteotomy. 39 cases, in which the superimposition deviation of the S-N plane on preoperative and postoperative radiographs were within 1mm were selected for this study. A comparative analysis was performed on a predetermined standard line of estimated values on prepoerative lateral cephalograms and of postoperative measured values on radiographs taken within 3 days after surgery. The following results were obtained. 1. Cases with simultaneous maxillary and mandibular surgery showed a great difference and standard deviation than cases in which surgery was performed on the mandible alone. 2. Of the cases in which surgery was performed on both jaws, the measured values of the mandible showed a greated difference but there was no statistical significance in all measuring points. (p<0.05) 3. Simultaneous maxillo-mandibular surgery group and only mandibular surgery group showed the least difference in Upper Incisor. Tip(U1) value, but Menton(Me) and Antegonial Notch(AgN) values exhibited a relatively great difference. 4. Of the cases in which surgery was performed on both jaws, the mean and standard deviation of immobilized group and downward movement group according to the difference of incisal movement direction showed a relatively small difference but a great difference was noted in forward and upward movement groups. 5. Of the cases in which surgery was performed on both jaws, the differenc of Upper Incisal Tip(U1) and Anterior Nasal Spine(ANS) values in both groups according to the amount of upward movement of the upper first molar were similar but the posterior Nasal Spine(PNS) value was significantly different in both groups. (p<0.05)