Department of Otolaryngology-Head and Neck Surgery, Madigan Army Medical Center, Tacoma.
Department of Radiology, Virginia Mason Medical Center, Seattle.
J Craniofac Surg. 2023 Jun 1;34(4):1278-1282. doi: 10.1097/SCS.0000000000009189. Epub 2023 Jan 25.
Gender-affirming facial surgery is a common intervention for transgender patients because of its ability to decrease the frequency of misgendering. Many anatomic targets can be addressed, but the mandible is the primary aspect of the lower third of the face that is manipulated during these procedures. This study's objective is to quantify the differences in cephalometric measurements between male and female mandibles on maxillofacial imaging, with the goal of identifying surgical targets for gender affirmation. A nonrandomized, retrospective, single-institution, case-control study of 387 patients who underwent maxillofacial computed tomography during 2017-2020 was performed. After excluding patients with imaging that did not capture the entire head or had deforming pathology of the face, a total of 113 patients were included. Cephalometric measurements that corresponded to areas reported by patients as sources of dysphoria were selected for analysis. These included mandibular width, ramus height, lateral flare, masseter volume, total face height, and the values of the mandibular angles in degrees. The relationship of masseter volume to the other measurements was also characterized. Significantly greater masseter volume was seen in males compared with females, and a greater masseter thickness was also seen in males. The mandibular angle was more acute in males than females. Aggregate analysis of muscle volume and thickness was positively correlated with ramus height, lateral flare, and mandibular width. Ramus, mental, and total facial height correlated directly with patient height in males but not in females. These data provide a normative baseline for planning lower facial gender-affirming surgery.
性别肯定性面部手术是跨性别患者的常见干预措施，因为它能够减少被误认的频率。许多解剖目标都可以得到解决，但下颌骨是这些手术中操作的下面部的主要方面。本研究的目的是量化男性和女性下颌骨在颌面成像中的头影测量差异，以确定性别肯定性手术的目标。这是一项非随机、回顾性、单机构、病例对照研究，共纳入了 2017 年至 2020 年期间接受颌面计算机断层扫描的 387 名患者。在排除了成像未捕获整个头部或存在面部变形性病变的患者后，共纳入了 113 名患者。选择与患者报告的苦恼源对应的头影测量指标进行分析。这些包括下颌骨宽度、下颌支高度、外侧膨出度、咬肌体积、总面高和下颌角的度数。还分析了咬肌体积与其他测量值的关系。与女性相比，男性的咬肌体积明显更大，男性的咬肌厚度也更大。男性的下颌角比女性更尖锐。肌肉体积和厚度的综合分析与下颌支高度、外侧膨出度和下颌骨宽度呈正相关。在男性中，下颌支、颏部和总面高与患者身高直接相关，但在女性中则不然。这些数据为规划下面部性别肯定性手术提供了正常参考基线。
