骨性Ⅲ类错患者双颌手术前后面部骨骼硬组织变化的三维研究

A three-dimensional study on the changes in facial hard tissues before and after bimaxillary surgery in patients with skeletal class Ⅲ malocclusion

目的探讨骨性Ⅲ类错畸形患者正颌手术前后面部骨骼硬组织变化规律,明确上颌骨Le Fort Ⅰ型截骨、下颌骨矢状劈开截骨所带来的面形轮廓三维空间变化范围及大小。方法收集30例行上颌骨Le Fort Ⅰ截骨前徙术+下颌骨双侧升支矢状劈开截骨后退术患者的资料,分别在术前2周内和术后6个月进行全头颅CT扫描检查,并在软件中进行头颅模型三维重建,于同一坐标系中完成标记点定点、测量,分析面部各区域硬组织解剖标志点的变化。结果上、下颌骨水平横向变化无统计学意义;矢状向变化具有统计学意义,上颌平均前徙2~3 mm,下颌平均后退5~6 mm,下颌后退量为上颌前徙量的2倍稍多,上颌骨发生逆时针旋转;垂直向下颌骨发生显著性上抬。结论双颌手术前后面部硬组织变化范围下颌大于上颌,面部整体变化表现为变短、饱满。手术设计时需考虑患者术后面形的变化。

Objective To explore the changes in facial hard tissues before and after orthognathic surgery in patients with skeletal Class Ⅲ malocclusion and to clarify the scope and size of changes of the three-dimensional space of facial contours caused by Le Fort Ⅰosteotomy and sagittal split osteotomy of the mandible to provides guidance for the design of a surgical plan.Methods Thirty patients in our department with skeletal Class Ⅲ malocclusion underwent bimaxillary surgery,including 11 males and 19 females with an average age of22.6 years.All patients underwent maxillary Le Fort Ⅰ osteotomy and lower jaw bilateral sagittal split ramus osteotomy（BSSRO） receding.Full head CT scan was performed within 2 weeks（T1） preoperative and 6 months postoperative（T2） in addition to three-dimensional reconstruction of the skull model.The marker points were fixed and measured in the same coordinate system,and the changes in hard tissue anatomical landmarks in the facial regions were analyzed.Results There were no significant horizontal and lateral changes in the maxillary and mandibular directions; the sagittal changes were statistically significant.The mean migration of the maxillary was 2 to 3 mm,and the average receded distance of the jaw was 5 to 6 mm.The amount of mandible retraction was twice more than that of the upper jaw,and the maxilla developed a counterclockwise rotation.The vertical mandible was significantly elevated.Conclusion The range of facial hard tissue changes in the mandible was greater than that of the maxilla after bimaxillary surgery.The overall change of facial appearance was full and less elongated.The changes of a patient′s postoperative facial shape should be taken into account during the surgical design phase.