目的：研究上颌Le FortⅠ型分块截骨术及双侧下颌升支矢状劈开术（bilateral sagittal split ramus osteotomy, BSSRO）对骨性Ⅲ类错牙合畸形患者髁突位置的影响。方法：对符合纳入标准的19名骨性Ⅲ类错牙合畸形患者的颞下颌关节间隙及髁突位置进行回顾性研究。所有患者分别于上颌Le FortⅠ型截骨及BSSRO术前1周内(T1)、术后1周内(T2)、术后3个月(T3)及术后6~14个月(T4)，行双侧颞下颌关节锥形束计算机断层（cone beam computed tomography，CBCT）扫描。在经过轴位断面上髁突最大内外径中点并与髁突最大内外径垂直的斜矢状断面上，按照Kamelchuk法测量双侧颞下颌关节前间隙、后间隙及上间隙，计算髁突位置参数，计算髁突在关节窝中位于前位、中位及后位等3种不同相对位置的分布比例，并对不同时期的测量结果进行统计分析。结果：T2时期双侧颞下颌关节前间隙、后间隙及上间隙［右侧：（2.78±1.23）mm、（2.47±0.89）mm、（3.07±0.85）mm；左侧：（2.93±0.83）mm、（2.69±1.14）mm、（3.44±1.16）mm］分别与T1［右侧：（1.81±0.95）mm、（1.65±0.55）mm、（2.13±0.52）mm；左侧：（2.12±1.05）mm、（1.79±0.59）mm、（2.15±0.93）mm］、T3［右侧：（2.08±1.25）mm、（1.79±0.68）mm、（1.80±0.76）mm；左侧：（2.05±0.75）mm、（1.99±0.94）mm、（2.14±0.71）mm］及T4［右侧：（1.94±0.77）mm、（1.81±0.69）mm、（2.05±0.69）mm；左侧：（1.89±0.69）mm、（1.80±0.61）mm、（2.19±0.75）mm)］时期比较，均增大，差异具有统计学意义（P＜0.05）；T1、T3及T4期双侧关节各间隙差异均无统计学意义（P＞0.05）；髁突位置参数及髁突相对位置分布比例在各时期的差异均无统计学意义（P＞0.05）。上述结果提示，T2时期髁突向下移动，但在T3时期髁突位置恢复至与术前一致的位置，并在T4时期保持稳定状态。结论：骨性Ⅲ类错牙合畸形患者在行上颌Le FortⅠ型分块截骨术及BSSRO术后，短期内髁突的位置可发生显著改变，但可逐渐恢复至术前髁突的位置并保持稳定。

Objective：To investigate the effect of segmental Le FortⅠosteotomy and bilateral sagittal split ramus osteotomy (BSSRO) on the condyle position in skeletal class Ⅲ malocclusion patients.Methods: In this retrospective study, 19 patients with skeletal class Ⅲ malocclusion who met the inclusion criteria were enrolled. All the patients underwent the segmental Le FortⅠ osteotomy and BSSRO. Cone beam computed tomography (CBCT) scans were performed in the following phases: T1: within one week before the surgeries; T2: within one week post-surgery;T3:three months post-surgery; T4: 6 to 14 months post-surgery. The posterior spaces, anterior spaces and the superior spaces of the bilateral temporomandibular joints were measured according to the Kamelchuk method respectively. The fossa ratios of the condyle and the distribution of the condyle positions related to the glenoid fossa (anterior, concentric and posterior position)were calculated. The results were analyzed statistically. Results:The posterior space, the anterior space and the superior space of bilateral temporomandibular joints in T2 phase［right: (2.78±1.23) mm, (2.47±0.89) mm, (3.07±0.85) mm; left: (2.93±0.83) mm, (2.69±1.14) mm, (3.44±1.16) mm］ showed significantly larger spaces than those in T1 phase ［right: (1.81±0.95) mm, (1.65±0.55) mm, (2.13±0.52) mm; left: (2.12±1.05) mm, (1.79±0.59) mm, (2.15±0.93) mm］,in T3 phase ［right: (2.08±1.25) mm, (1.79±0.68) mm, (1.80±0.76) mm; left: (2.05±0.75) mm, (1.99±0.94) mm, (2.14±0.71) mm］ and in T4 phase ［right: (1.94±0.77) mm, (1.81±0.69) mm, (2.05±0.69) mm; left: (1.89±0.69) mm, (1.80±0.61) mm, (2.19±0.75) mm］, P＜0.05. No significant differences were observed among T1,T3 and T4 phases in the terms of the joint spaces of both sides(P＞0.05).The fossa ratio and the condyle position related to the glenoid fossa had no significant difference in all the four phases(P＞0.05).The results suggested that the condyle moved downward in T2 phase and changed to the original presurgery position in T3 phase, then keot stable in T4 phase.Conclusion:Segmental Le FortⅠ osteotomy and BSSRO caused significant and transient changes of the condyle position in skeletal classⅢ malocclusion patients. However, the condyle tended to move back to the original pre-surgery position and might keep stable.