Understanding bilateral pelvic symmetry can be useful for analyzing complex pelvis anatomy and simplifying difficult procedures for pelvic fractures. This paper aims to quantify the degree of regional pelvic symmetry using computer-based methods. CT scans of 30 intact pelvises were digitized into 3D models and regions were defined: the ilium, acetabulum, pubis, and ischium. The right hemipelvis was aligned with the left, and deviations between the two models were quantified using method 1 (global registration) and method 2 (local registration). Symmetry was evaluated using the root mean square (RMS) of the deviations and the percentage of points within preset thresholds of ± 2 mm and ± 1 mm. The results showed that > 86% of points are within the ± 2 mm deviation threshold and average RMS are < 1.33 mm. For all regions, method 2 showed lower deviations than method 1. The pubis and ischium regions showed a large difference in symmetry between the two methods indicating high local symmetry, but a degree of global asymmetry. Conversely, the acetabular and iliac regions showed similar levels of symmetry with the two methods. When evaluated locally, the pelvic regions can be considered highly symmetric; the acetabulum is highly symmetric globally as well. These findings can be used in future studies to assess the feasibility of patient-specific implants using the mirrored contralateral hemipelvis as a template for unilateral pelvic fracture fixation.

Graphical abstract

中文翻译：

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区域特定骨盆对称性的定量分析

了解双侧骨盆对称性有助于分析复杂的骨盆解剖结构和简化骨盆骨折的困难手术。本文旨在使用基于计算机的方法量化区域骨盆对称的程度。30 个完整骨盆的 CT 扫描被数字化为 3D 模型并定义区域：髂骨、髋臼、耻骨和坐骨。右半骨盆与左侧对齐，使用方法 1（全局配准）和方法 2（局部配准）量化两个模型之间的偏差。使用偏差的均方根 (RMS) 和预设阈值 ± 2 mm 和 ± 1 mm 内的点百分比来评估对称性。结果显示 > 86% 的点在 ± 2 mm 偏差阈值内，平均 RMS < 1.33 mm。对于所有地区，方法 2 显示出比方法 1 更低的偏差。耻骨和坐骨区域在两种方法之间显示出很大的对称性差异，表明局部对称性较高，但存在一定程度的全局不对称性。相反，两种方法的髋臼和髂骨区域显示出相似的对称水平。在局部评估时，骨盆区域可以被认为是高度对称的；髋臼在整体上也是高度对称的。这些发现可用于未来的研究，以评估使用镜像对侧半骨盆作为单侧骨盆骨折固定模板的患者特异性植入物的可行性。髋臼和髂骨区域显示出与两种方法相似的对称水平。在局部评估时，骨盆区域可以被认为是高度对称的；髋臼在整体上也是高度对称的。这些发现可用于未来的研究，以评估使用镜像对侧半骨盆作为单侧骨盆骨折固定模板的患者特异性植入物的可行性。髋臼和髂骨区域显示出与两种方法相似的对称水平。在局部评估时，骨盆区域可以被认为是高度对称的；髋臼在整体上也是高度对称的。这些发现可用于未来的研究，以评估使用镜像对侧半骨盆作为单侧骨盆骨折固定模板的患者特异性植入物的可行性。

图形概要