Vu Viet Duc, Takahara Namiaki, Iwasaki Takuya, Kurasawa Yasuhiro, Tomomatsu Nobuyoshi, Yoda Tetsuya
Department of Maxillofacial Surgery, Graduate School of Medical and Dental Sciences, Institute of Science Tokyo, 1 - 5- 45Bunkyo-Ku, YushimaTokyo, 113 - 8549, Japan.
Clin Oral Investig. 2025 Apr 10;29(5):236. doi: 10.1007/s00784-025-06294-5.
To evaluate the effectiveness and stability of a modified overlap method for manipulating proximal segments (PSs) during bilateral sagittal split osteotomy for correcting facial asymmetry and to identify risk factors contributing to Menton horizontal relapse.
This retrospective cohort study involved 62 consecutive adults with class III asymmetry who underwent bimaxillary surgery. Patients were classified in two groups according to surgical techniques: the overlap group (n = 31), in which the non-deviated PS was flared outward before aligning with the distal segment (DS), and the conventional group (n = 31), in which the PSs and DS were aligned in maximum contact. Computed tomographic scans were taken before surgery (T0), postoperative 1 week (T1) and 1 year (T2). Transverse ramus measurements and maxillo-mandibular segments movements were intergrouply compared. Correlations of Menton horizontal relapse with preoperative and intraoperative factors were also assessed.
From T1-T0, the overlap group showed greater reductions in discrepancies for gonial width (4.09 ± 3.49 mm) and coronal ramus angle (3.67° ± 3.44°) compared to the conventional group (1.76 ± 2.55 mm; 1.70° ± 3.16°) (p = 0.004, 0.023). From T2-T1, relapses in both groups were ≤ 2 mm and ≤ 2°. No correlation was found between surgical techniques and Menton horizontal relapse.
The overlap method demonstrates effectiveness in correcting facial asymmetry, resulting in greater reductions in ramus discrepancies while maintaining mandibular stability one year postoperatively.
For severe facial asymmetry, clinicians may consider using the overlap technique to enhance postoperative facial appearance.
评估改良重叠法在双侧矢状劈开截骨术中处理近心段以矫正面部不对称的有效性和稳定性，并确定导致颏部水平复发的危险因素。
这项回顾性队列研究纳入了62例连续接受双颌手术的Ⅲ类不对称成年患者。根据手术技术将患者分为两组：重叠组（n = 31），其中未偏斜的近心段在与远心段对齐前向外张开；传统组（n = 31），其中近心段和远心段以最大接触对齐。在术前（T0）、术后1周（T1）和1年（T2）进行计算机断层扫描。对两组间的下颌支横向测量值和上颌-下颌节段运动进行比较。还评估了颏部水平复发与术前和术中因素的相关性。
从T1到T0，与传统组（1.76±2.55mm；1.70°±3.16°）相比，重叠组在角宽度差异（4.09±3.49mm）和冠状下颌支角（3.67°±3.44°）方面的减小幅度更大（p = 0.004，0.023）。从T2到T1，两组的复发均≤2mm且≤2°。未发现手术技术与颏部水平复发之间存在相关性。
重叠法在矫正面部不对称方面显示出有效性，在术后一年维持下颌稳定性的同时，能更大程度地减小下颌支差异。
对于严重面部不对称，临床医生可考虑使用重叠技术来改善术后面部外观。
