Changes of Transverse Mandibular Width in Set-Back Mandibular Surgery: Sagittal Split versus Intraoral Verticosagittal Osteotomy

Aim: This study was performed to evaluate the movement of the proximal segment following different methods of ramus osteotomy that is one of the side effects of orthognathic surgery. Theoretically, with intraoral verticosagittal ramus osteotomy, it can minimize the movement of the proximal segment. The changes in the intergonal distance of mandible and the angle of the ramus flaring in two methods of osteotomy have been compared in this study. Materials and Methods: In this randomized clinical trial, included 60 patients (32 males) with mandibular prognathism and without any asymmetry were selected and divided into two groups (n = 30). One group underwent bilateral sagittal split ramus osteotomy technique to achieve mandibular setback and the other by the intraoral verticosagittal ramus osteotomy technique. Intergonial width and inner-ramal angle in the transverse plane were measured on radiographs preoperatively and 1 and 12 weeks postoperatively. Data were analyzed using covariance test with the significance level set at P 0.1). Conclusion: Considering our findings, there was no significant difference between two ramus osteotomy techniques regarding changes in mandibular width and inter-ramal flaring angle.

双侧下颌升支矢状劈开截骨后退术对下颌骨宽度及形态的影响

目的通过对下颌前突患者行双侧下颌升支矢状劈开截骨后退术前后头颅正侧位定位片硬组织结构变化的洲量分析,评价手术对患者下颌骨宽度及形态的影响。方法选择1997年至2001年在我中心行双侧下颌升支矢状劈开术的下颌前突患者18例,男性9例,女性9例,平均年龄22．22岁,所有患者手术前、术后一周、术后一年拍摄静止位头颅正侧位定位片,在正位片上测量下颌骨宽度(Go-Go),并从头颅正侧位定位片上测量与下颌骨宽度变化有关的参数数值。结果①下颌骨宽度由107．30mm±5．84mm(术前)增加至109．24mm±5．72mm(术后一周)、109．31mm±5．66mm(术后一年),其中有4例宽度减小,1例保持不变。13例增加,②下颌骨宽度术前、术后一用、术后一年的方差分析结果表明差别有显著性。③分析表明下颌骨宽度变化与各参数变化之间没有线性相关。结论①下颌骨宽度在双侧下颌升支矢状劈开截骨术后较术前有轻微增大,但对容貌没有大的影响。②下颌骨宽度变化机制可能与颞下颌关节功能改变有关。