Perelman School of Medicine; Department of Orthopedic Surgery; University of Pennsylvania; Philadelphia; Penssylvania; USA.
Stud Health Technol Inform. 2021 Jun 28;280:53-57. doi: 10.3233/SHTI210434.
The pathomechanism of spinal deformity development in adolescent idiopathic scoliosis (AIS) has been related to the sagittal curvature of the spine. It is not known how the variations in the sagittal profile relates to the coronal deformity patterns in AIS. A total of 70 Lenke 1 and 50 Lenke 5 AIS patients were included retrospectively. A finite element (FE) model was developed for each spine where the sagittal spinal curvatures were modeled as 2D S shaped elastic rods. Transverse plane deformation patterns of these rods under physiological loading were determined and clustered based on their similarities. The patients' characteristics, including the Lenke type, and the spinal measurements in these deformation pattern clusters were statistically compared. Three different axial deformation patterns were determined from the FE simulations of the 120 sagittal curves. Two axial groups were looped shaped in opposing directions (Group I and III) and one was lemniscate shaped (Group II). 94% of the patients in Groups I and II were Lenke 1 and 100% of Group III was Lenke 5. The position of the sagittal inflection point moved downward from Group I-III resulting in significantly different ratio of the arc lengths above and below the sagittal inflection points for Groups I, II and III (0.49±0.59, 1.15±0.44, and 3.22±1.8). A classification of idiopathic scoliosis, based on the biomechanics of S-shaped flexible rods deformation could distinguish between different coronal curve types. The geometrical parameters of the sagittal profiles in the axial deformation pattern groups were significantly different.
脊柱畸形发展的病理机制与脊柱矢状曲度有关。目前尚不清楚矢状轮廓的变化与特发性脊柱侧凸（AIS）的冠状畸形模式有何关系。共回顾性纳入 70 例 Lenke 1 型和 50 例 Lenke 5 型 AIS 患者。为每个脊柱建立有限元（FE）模型，将矢状脊柱曲率建模为 2D S 形弹性杆。在生理负荷下确定这些杆的横断平面变形模式，并根据相似性进行聚类。根据这些变形模式聚类，统计比较患者特征，包括 Lenke 类型和脊柱测量值。从 120 个矢状曲线的 FE 模拟中确定了三种不同的轴向变形模式。两个轴向组呈相反方向的环形（I 组和 III 组），一个是lemniscate 形（II 组）。I 组和 II 组的 94%患者为 Lenke 1 型，III 组的 100%患者为 Lenke 5 型。矢状拐点的位置从 I-III 组向下移动，导致 I、II 和 III 组矢状拐点上下弧长比显著不同（0.49±0.59、1.15±0.44 和 3.22±1.8）。基于 S 形柔性杆变形的生物力学，特发性脊柱侧凸的分类可以区分不同的冠状曲线类型。轴向变形模式组的矢状轮廓几何参数有显著差异。
