矢向分裂骨切開術治療下顎前突症之術後評估

　　　　　本究研究報告之目的，在於研究施行下顎骨矢向分裂骨切開術病例，於術後不同時期之頦部術後復發及術後矢向、垂直向復發和下顎骨矢向後置量、垂直高度改變之間的相關性。材料共有27位病例之術前〔T1〕、手術後六星期〔T2〕、手術後六個月〔T3〕及手術後一年〔T4〕之測顱攝影X光片，測量其不同時期Pog點之間的差別。結果顯示，一、手術後六星期之Pog點〔T2-T1〕平均後退7.6mm向下1.9mm，術後一年之平均矢向及垂直向復發〔T4-T2〕分別為門前2.3mm及往上1.1mm。術後一年之平均復發方向為和7°於SN之平面呈22.6°夾角，往上、往前移動。二、術後一年之矢向復發有86%發生於術後前六個月內〔T3-T2〕，術後六個月到一年〔T2-T1〕及之垂直向下變化量〔T2-T1〕之間有相關性存在〔r=0.58及r=0.67，兩個p≦0.001〕。四、術後一年之垂直向復發〔T4-T2〕和下顎骨Pog點之垂直向下變化量〔T2-T1〕之間有相關性存在〔r=0.67， p≦0.001〕。
　　　　　The present study was undertaken to evaluate the postoperative relapse from the period of unwiring to 1 year postoperatively and its correlation to the amount of mandibular setback and change in vertical dimension after mandibular bilateral sagittal split osteotomy. Twenty-seven patients were evaluated cephalometrically by the time preoperatively, 6 weeks, 6 months and 1 year postoperatively. It was found that 1) the average amount of mandibular setback at pogonion point, 6weeks postoperatively, is 7.6mm backward and 1.9mm downward, 2) the average amount of horizongal relapse at pognoion point, 6 months and 1 year postoperatively, are 1.9mm and 2.3mm respectively. 86% of the horizontal relapse, 1 year postoperatively, occurs in the first 6 moths after removal of intermaxillary fization, 3) the average amount of vertical relapse at pogonion point, 6 months after removal of intermaxillary fixation, 4) the amount of 1 year postoperatively horizontal relapse is significantily correlated both with the amount of horizontal mandibular set back and vertical downward change (r=0.58, 067, p<0.001), whereas the amount of vertical relapse is with the vertical downward change only, but horizontal setback ins’t.