Ganesh N Praveen, Maity Pushan, Raja D Alagar, Rao R V M Surya, Narayanamurthy S, Prasath A
Dept of Plastic, Reconstructive and Craniomaxillofacial Surgery, Saveetha Medical College and Hospital, Chennai, India.
Dept of Plastic, Reconstructive and Craniomaxillofacial Surgery, Saveetha Medical College and Hospital, Chennai, India.
Br J Oral Maxillofac Surg. 2020 Nov;58(9):e104-e108. doi: 10.1016/j.bjoms.2020.07.016. Epub 2020 Aug 13.
In orbital floor reconstruction, the need for the orbital implant to reach the exact position of the posteromedial ledge is essential, but owing to the complex anatomy of the region, visualisation of the ledge may be difficult. Several morphometric studies, both radiographic and cadaveric, have calculated a mean length from the orbital rim to the ledge. However, those linear measurements are unreliable and possess a higher margin of error for intraoperative guidance. This study attempts to triangulate the position of the posterior ledge from three easily accessible and reproducible points on the orbit and tries to provide a better guideline. A total of 50 patients (25 male and 25 female) with no history of orbital trauma or orbital surgery were selected randomly for this study. Computed tomography (CT) of both orbits, was done from three anatomically consistent and reproducible points: the infraorbital rim just above the infraorbital foramen (point A), hamulus lacrimalis (point B), and the most anterior point of the inferior orbital fissure (point C). The distance from these landmarks to the posterior ledge was measured using DICOM imaging software. A polygonal template was fabricated using the data obtained, which was used for intraoperative guidance. The mean (SD) distance to the posterior ledge from point A was 32.99 (1.35) mm, from point B was 31.36 (1.31) mm, and from point C was 20.19 (1.40) mm. There were no significant differences between left and right orbit or between male and female subjects. The template guides the shape, size, and direction of the orbital implant, reducing the risk of undersized or misplaced implants.
在眶底重建中，眼眶植入物需精确放置于后内侧壁的准确位置至关重要，但由于该区域解剖结构复杂，后壁的可视化可能存在困难。多项影像学和尸体测量的形态学研究已计算出从眶缘到后壁的平均长度。然而，这些线性测量结果并不可靠，在术中指导时误差 margin 较大。本研究试图从眼眶上三个易于触及且可重复的点对后内侧壁的位置进行三角测量，并尝试提供更好的指导方针。本研究随机选取了 50 例无眼眶外伤或眼眶手术史的患者（25 例男性和 25 例女性）。从三个解剖结构一致且可重复的点对双侧眼眶进行计算机断层扫描（CT）：眶下孔上方的眶下缘（A 点）、泪骨钩（B 点）和眶下裂最前点（C 点）。使用 DICOM 成像软件测量这些标志点到后内侧壁的距离。利用所获数据制作了一个多边形模板，用于术中指导。从 A 点到后内侧壁的平均（标准差）距离为 32.99（1.35）mm，从 B 点为 31.36（1.31）mm，从 C 点为 20.19（1.40）mm。左右眼眶之间或男性与女性受试者之间无显著差异。该模板可指导眼眶植入物的形状、大小和方向，降低植入物尺寸过小或位置不当的风险。
