Quantitative dynamic evaluation of spino-pelvic motion in subjects with spinal deformity using optical motion analysis is currently lacking. The aim of this study was to develop and validate subject-specific, thoracolumbar spine multi-body skeletal models for evaluating spino-pelvic kinematics in a spinal deformity population.

A new workflow for creating subject-specific spino-pelvic models in a weight-bearing position through computed tomography (CT) and biplanar radiography is described. As part of a two-step validation process the creation of such a model was first validated against a ground truth CT reconstruction of a plastinated cadaver. Secondly, biplanar radiographic images of one healthy and 12 adult spinal deformity subjects were obtained in two standing positions: upright and bent. Two subject-specific models for each of these subjects were then created to represent both standing positions. The result of inverse kinematics solutions, simulating the specific bending motion using the upright models, are compared with the models created in bent position, quantifying the marker-based spino-pelvic tracking accuracy.

The workflow created spinal deformity models with mean accuracies between 0.71–1.95 mm and 1.25–2.27° for vertebral positions and orientations, respectively. In addition, the mean marker-based spino-pelvic tracking accuracies were between 0.9–1.8 mm and 2.9–5.6° for vertebral positions and rotations, respectively.

This study presented the first validated biplanar radiography-based method to generate subject-specific spino-pelvic, rigid body models that allows the inclusion of subject-specific bone geometries, the personalization of the 3D weight-bearing spinal alignment with accuracy comparable to clinically used software for 3D reconstruction, and the localization of external markers in spinal deformity subjects. This work will allow new concepts of dynamic functionality evaluation of patients with spinal deformity.

目前尚缺乏使用光学运动分析对脊柱畸形受试者的脊柱骨盆运动进行动态定量评估的方法。这项研究的目的是开发和验证特定于受试者的胸腰椎多体骨骼模型，以评估脊柱畸形人群的脊柱骨盆运动学。

描述了一种新的工作流程，该工作流程可通过计算机断层扫描（CT）和双平面X线摄影在承重位置创建受检者特定的脊柱骨盆模型。作为两步验证过程的一部分，首先针对塑化尸体的地面真相CT重建验证了此模型的创建。其次，在两个直立姿势和弯曲姿势中获得了一名健康的和12名成人脊柱畸形受试者的双平面X射线照相图像。然后，针对这些受试者中的每个受试者创建了两个特定于受试者的模型，以代表两个站立姿势。使用直立模型模拟特定弯曲运动的逆运动学解决方案的结果，与在弯曲位置创建的模型进行了比较，从而量化了基于标记的脊柱骨盆跟踪的准确性。

该工作流程创建了脊椎畸形模型，其椎骨位置和方向的平均精度分别在0.71–1.95 mm和1.25–2.27°之间。此外，椎骨位置和旋转的平均标记物脊柱骨盆追踪平均准确度分别在0.9-1.8 mm和2.9-5.6°之间。

这项研究提出了第一个经过验证的基于双平面X射线照相法的方法，可以生成特定于受试者的脊柱骨盆，刚体模型，该模型可以包含特定于受试者的骨骼几何形状，3D负重脊柱对准的个性化，其准确性可与临床使用3D重建软件，以及在脊柱畸形受试者中定位外部标记的软件。这项工作将允许脊柱畸形患者动态功能评估的新概念。