Hwang Soon-Jung, Haers Piet E, Seifert Burkhardt, Sailer Hermann F
Department of Oral and Maxillofacial Surgery, College of Dentistry, Seoul National University, South Korea.
J Craniomaxillofac Surg. 2004 Apr;32(2):103-11. doi: 10.1016/j.jcms.2003.09.007.
Condylar resorption following orthognathic surgery is an important cause of late skeletal relapse. However, its pathogenesis is not well understood. The purpose of this study was to find non-surgical risk factors for condylar resorption after orthognathic surgery.
In this retrospective study, 17 patients (Group I) who developed postoperative condylar resorption were selected. These patients were compared with 22 patients (Group II) without postoperative condylar resorption, but who showed mandibular hypoplasia with a preoperative high mandibular plane angle of more than 40 degrees.
Possible non-surgical risk factors were sought by analysing clinical and radiological data collected preoperatively and immediately, 6 weeks, and 1 and 2 years postoperatively.
There was no significant difference of gender distribution between the two groups. Patients in Group I were significantly younger (p=0.02) than those in Group II. The incidence of temporomandibular joint dysfunction in both groups was similar preoperatively, but was significantly higher (p=0.001) postoperatively in Group I. The posterior inclination of the condylar neck in Group I was also significantly greater (p<0.001). The preoperative mandibular plane angle in Group I (mean value: 49.4 degrees ) was significantly greater (p=0.005) than in Group II (mean value: 44.9 degrees ). The preoperative SNB angle, overbite, and posterior facial height and ratio (posterior/anterior facial heights) in Group I were significantly smaller (p<0.05).
The present study suggests that the posteriorly inclined condylar neck should be considered as a relevant non-surgical risk factor.
正颌外科手术后髁突吸收是晚期骨骼复发的重要原因。然而，其发病机制尚不清楚。本研究的目的是寻找正颌外科手术后髁突吸收的非手术风险因素。
在这项回顾性研究中，选取了17例术后发生髁突吸收的患者（第一组）。将这些患者与22例未发生术后髁突吸收但术前下颌平面角大于40度且下颌发育不全的患者（第二组）进行比较。
通过分析术前、术后即刻、6周、1年和2年收集的临床和放射学数据，寻找可能的非手术风险因素。
两组性别分布无显著差异。第一组患者比第二组患者明显年轻（p = 0.02）。两组术前颞下颌关节功能障碍的发生率相似，但第一组术后显著更高（p = 0.001）。第一组髁突颈部的后倾角也明显更大（p < 0.001）。第一组术前下颌平面角（平均值：49.4度）明显大于第二组（平均值：44.9度）（p = 0.005）。第一组术前的SNB角、覆合、后牙高度及比例（后牙高度/前牙高度）明显更小（p < 0.05）。
本研究表明，髁突颈部后倾应被视为一个相关的非手术风险因素。
