PURPOSE To define the longitudinal rotation axis around which individual vertebrae rotate, and to establish the various extra- and intravertebral rotation patterns in thoracic adolescent idiopathic scoliosis (AIS) patients, for better understanding of the 3D development of the rotational deformity. METHODS Seventy high-resolution CT scans from an existing database of thoracic AIS patients (Cobb angle: 46°-109°) were included to determine the vertebral axial rotation, rotation radius, intravertebral axial rotation, and local mechanical torsion for each spinal level, using previously validated image processing techniques. RESULTS For all levels, the longitudinal rotation axis, from which the vertebrae rotate away from the midline, was localized posterior to the spine. The axis became closer to the spine at the apex: apex, r = 11.5 ± 5.1 cm versus two levels above (radius = 15.8 ± 8.5 cm; p < 0.001) and beneath (radius = 14.2 ± 8.2 cm; p < 0.001). The vertebral axial rotation, intravertebral axial rotation, and local mechanical torsion of the vertebral bodies were largest at the apex (21.9° ± 7.4°, 8.7° ± 13.5° and 3.0° ± 2.5°) and decreased toward the neutral, junctional zones (p < 0.001). CONCLUSION In AIS, the vertebrae rotate away around an axis that is localized posterior to the spine. The distance between this axis and the spine is minimal at the apex and increases gradually to the neutral zones. The vertebral axial rotation is accompanied by smaller amounts of intravertebral rotation and local mechanical torsion, which increases toward the apical region. The altered morphology and alignment are important for a better understanding of the 3D pathoanatomical development of AIS and better therapeutic planning for bracing and surgical intervention. These slides can be retrieved under Electronic Supplementary Material.

中文翻译：

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基于CT的右胸青少年特发性脊柱侧凸的椎体和椎体旋转研究。

目的定义胸椎特发性脊柱侧凸（AIS）患者的椎骨旋转的纵向旋转轴，并建立各种椎体外和椎体旋转模式，以更好地理解旋转畸形的3D发展。方法包括来自现有的胸AIS患者数据库（Cobb角：46°-109°）的70次高分辨率CT扫描，以确定每个脊椎水平的椎骨轴向旋转，旋转半径，椎骨内部旋转以及局部机械扭转，使用先前验证的图像处理技术。结果对于所有水平，椎骨从中线旋转离开的纵向旋转轴都位于脊柱后方。轴在顶点处变得更靠近脊椎：顶点，r = 11.5±5。1厘米，而上方（半径= 15.8±8.5厘米; p <0.001）和下方（半径= 14.2±8.2 cm; p <0.001）有两个水平。椎体的椎体轴向旋转，椎内轴向旋转和局部机械扭转在顶点处最大（21.9°±7.4°，8.7°±13.5°和3.0°±2.5°），并向中性的交界区域减小（ p <0.001）。结论在AIS中，椎骨绕着位于脊柱后部的轴旋转离开。该轴与脊椎之间的距离在顶点处最小，并逐渐增加到中性区域。椎骨的轴向旋转伴随着较小量的椎骨内部旋转和局部机械扭转，其向心尖区域增加。形态和排列的改变对于更好地了解AIS的3D病理解剖学发展以及更好的支架和手术干预治疗计划至关重要。这些幻灯片可以在电子补充材料下找到。