Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Key Laboratory of Oral Medicine, Department of Oral and Maxillofacial Surgery, Guangzhou Institute of Oral Disease, Affiliated Stomatology Hospital of Guangzhou Medical University, No. 39 Huangsha Avenue, Guangzhou, 510150, China.
Stomatology Department, Zhujiang Hospital of Southern Medical University, Guangzhou, 510282, China.
Surg Radiol Anat. 2022 Apr;44(4):551-558. doi: 10.1007/s00276-022-02912-z. Epub 2022 Mar 18.
The purpose of this study was to investigate short- and long-term postoperative changes of both morphology and transverse stability in mandibular ramus after intraoral vertical ramus osteotomy (IVRO) in patients with jaw deformity using three-dimensional (3D) orthognathic surgery planning treatment software for measurement of distances and angles.
This retrospective study included consecutive patients with skeletal Class III malocclusion who had undergone intraoral vertical ramus osteotomy and computed tomography images before (T0), immediately after (T1), and 1 year after (T2) surgery. Reference points, reference lines and evaluation items were designated on the reconstructed 3D surface models to measure distances, angles and volume. The average values at T0, T1, T2 and time-dependent changes in variables were obtained.
After surgery, the condylar length, ramal height, mandibular body length and mandibular ramus volume were significantly decreased (P < 0.01), while clinically insignificant change was observed from T1 to T2. The angular length was increased immediately after surgery (P < 0.05), but it was decreased 1 year after surgery (P < 0.05). Lateral ramal inclination showed significant increase after surgery (P < 0.05) and maintained at T2.
Changes in the morphology of the mandibular ramus caused by IVRO do not obviously bring negative effect on facial appearance. Furthermore, despite position and angle of mandibular ramus changed after IVRO, good transverse stability was observed postoperatively. Therefore, IVRO technique can be safely used without compromising esthetic results.
本研究旨在通过三维（3D）正颌手术规划治疗软件测量距离和角度，探讨颌骨畸形患者接受口内垂直下颌骨劈开术（IVRO）后下颌支形态和横向稳定性的短期和长期术后变化。
本回顾性研究纳入了连续接受口内垂直下颌骨劈开术的骨骼 III 类错畸形患者，并在术前（T0）、术后即刻（T1）和术后 1 年（T2）进行了计算机断层扫描。在重建的 3D 表面模型上指定参考点、参考线和评估项目，以测量距离、角度和体积。获得 T0、T1、T2 时的平均值和变量的时间依赖性变化。
手术后，髁突长度、下颌支高度、下颌体长度和下颌支体积明显减小（P < 0.01），而 T1 到 T2 时观察到临床意义不大的变化。术后即刻角长度增加（P < 0.05），但术后 1 年时减少（P < 0.05）。外侧下颌支倾斜度术后明显增加（P < 0.05），并在 T2 时保持不变。
IVRO 引起的下颌支形态变化不会对面部外观产生明显的负面影响。此外，尽管 IVRO 后下颌支的位置和角度发生了变化，但术后横向稳定性良好。因此，IVRO 技术可以安全使用，而不会影响美观效果。
