Hou Min, Yu Tian-Ping, Wang Jian-Guo
Professor of Oral and Maxillofacial Surgery, Department of Orthognathic Surgery, Tianjin Stomatological Hospital of Nankai University, Tianjin, China.
Master, Tianjin Medical University, Tianjin, China.
J Oral Maxillofac Surg. 2015 May;73(5):985-93. doi: 10.1016/j.joms.2014.07.007. Epub 2014 Jul 17.
To evaluate the split patterns of the mandibular ramus in sagittal split ramus osteotomy (SSRO) using cone-beam computed tomography (CBCT) and examine the related anatomic features that may be associated with these split patterns.
The authors designed and implemented a retrospective cohort study and enrolled a sample composed of consecutive patients with different maxillofacial deformities who underwent an SSRO from July 2011 through October 2012 at the Department of Orthognathic Surgery at the Tianjin Stomatological Hospital of Nankai University. The split patterns, which were selected at random at 1 side per patient, were evaluated by CBCT as the outcome variable 1 month after the operation. The predictor variable was composed of a set of heterogeneous anatomic variables that could be associated with the split patterns. Type I split was defined as a split at the lingual side near the mylohyoid sulcus. Type II split was defined as a split at the posterior border of the mandibular ramus. Appropriate bivariate and regression statistics were computed, and the level of statistical significance was set at a P value less than .05.
One hundred thirty patients with different maxillofacial deformities (62 male and 68 female; mean age, 23 yr) underwent an SSRO. Two types of split patterns of the mandibular ramus were observed in SSRO: a split at the lingual side near the mylohyoid sulcus, which occurred in 75.38% of patients, and split at the posterior border region of the mandibular ramus, which occurred in 24.62% of patients. No fracture lines were observed through the mandibular canal. The thickness of the lingual cortical bone between the mandibular canal and the posterior border of the ramus was significantly associated with the split patterns (P < .05). The thickness of the cortical bone in the posterior border of the ramus, the degree of the mandibular angle, and the shapes of the mandibular ramus in the axial plane also were found to influence these split patterns. There was no meaningful association between the split patterns and a patient's age and gender.
The split patterns of the mandibular ramus during SSRO were influenced by some anatomic features of the mandibular ramus. Therefore, examining the anatomy of the mandible with CBCT before surgery may play an important role in predicting the split patterns of the mandibular ramus during SSRO.
使用锥形束计算机断层扫描（CBCT）评估矢状劈开下颌支截骨术（SSRO）中下颌支的劈开模式，并研究可能与这些劈开模式相关的解剖学特征。
作者设计并实施了一项回顾性队列研究，纳入了2011年7月至2012年10月在南开大学天津口腔医院正颌外科接受SSRO的连续不同颌面畸形患者组成的样本。每位患者随机选取一侧的劈开模式，术后1个月通过CBCT评估作为结果变量。预测变量由一组可能与劈开模式相关的异质性解剖变量组成。I型劈开定义为在靠近下颌舌骨沟的舌侧劈开。II型劈开定义为在下颌支后缘劈开。计算了适当的双变量和回归统计量，统计学显著性水平设定为P值小于0.05。
130例不同颌面畸形患者（男性62例，女性68例；平均年龄23岁）接受了SSRO。在SSRO中观察到两种下颌支劈开模式：在靠近下颌舌骨沟的舌侧劈开，发生在75.38%的患者中；在下颌支后缘区域劈开，发生在24.62%的患者中。未观察到穿过下颌管的骨折线。下颌管与下颌支后缘之间舌侧皮质骨的厚度与劈开模式显著相关（P < 0.05）。还发现下颌支后缘皮质骨的厚度、下颌角的角度以及轴向平面上下颌支的形状会影响这些劈开模式。劈开模式与患者的年龄和性别之间没有有意义的关联。
SSRO过程中下颌支的劈开模式受下颌支一些解剖学特征的影响。因此，术前用CBCT检查下颌骨的解剖结构可能在预测SSRO过程中下颌支的劈开模式方面发挥重要作用。
