Jozaghi Yelda, Chan Harley H L, Davies Joel C, Irish Jonathan C
Department of Otolaryngology - Head and Neck Surgery/Surgical Oncology.
Guided Therapeutics (GTx) Program, TECHNA Institute, University of Toronto, Princess Margaret Cancer Centre, Toronto, Canada.
J Craniofac Surg. 2019 Sep;30(6):1888-1890. doi: 10.1097/SCS.0000000000005368.
Surgical precision in the reconstruction of the orbital floor is crucial to functional visual and aesthetic outcomes. Increasingly, computer-aided design is being utilized to aid in precise preoperative planning by using the mirror images of the unaffected side. The authors aim to use 3-dimensional (3D) quantitative analysis to establish whether the native orbital floor topography is sufficiently symmetric to support this practice.
Ten high resolution head and neck computed tomography scans of patients without periorbital pathology were obtained. These were imported into a 3D medical image processing software and segmented to isolate bilateral orbital floors. Each native orbital floor was compared to the mirror image of the contralateral side by conformance map computation. Data collection included measures of 25% and 75% quartile, median, mean, standard deviation, and root-mean-square (RMS).
The topographic analysis demonstrated a high degree of topographic conformance with a mean RMS of 0.58 ± 0.37 mm. Further volumetric analysis comparing the total orbital volume between each side also demonstrates a high degree of volumetric symmetry with a mean difference of 0.55 mL (P = 0.30).
Comparison of the native orbital floor and the mirror image of the contralateral side by conformance map computation and volumetric analysis demonstrated a high degree of morphologic similarity. The native orbital floor topography provides optimal symmetry to support mirror imaging techniques used in orbital floor reconstruction.
眼眶底重建术中的手术精度对于视觉功能和美学效果至关重要。越来越多地，计算机辅助设计被用于通过使用未受影响侧的镜像来辅助精确的术前规划。作者旨在使用三维（3D）定量分析来确定天然眼眶底地形是否足够对称以支持这种做法。
获取了10例无眶周病变患者的高分辨率头颈部计算机断层扫描。将这些图像导入3D医学图像处理软件并进行分割以分离双侧眼眶底。通过一致性图计算将每个天然眼眶底与对侧的镜像进行比较。数据收集包括25%和75%四分位数、中位数、均值、标准差和均方根（RMS）的测量值。
地形分析显示出高度的地形一致性，平均RMS为0.58±0.37mm。进一步比较两侧之间总眼眶体积的体积分析也显示出高度的体积对称性，平均差异为0.55mL（P = 0.30）。
通过一致性图计算和体积分析对天然眼眶底与对侧镜像进行比较，显示出高度的形态相似性。天然眼眶底地形提供了最佳的对称性，以支持眼眶底重建中使用的镜像成像技术。
