Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
Department of Biomedical Engineering, College of Biomedical Science& Engineering, Inje University, Gyeongnam, Republic of Korea.
J Clin Neurosci. 2020 Mar;73:304-307. doi: 10.1016/j.jocn.2020.01.053. Epub 2020 Jan 18.
The purpose of this study is to investigate the effect of the cross-link position on the rod fracture phenomenon during pedicle subtraction osteotomy (PSO) surgery using finite element model (FEM).
A three-dimensional finite element model of a lumbar spine with sagittal imbalance was constructed using computed tomography data of a 65-year-old female patient. After simulating the standard PSO at the L4 level, we constructed four models, specifically a model without a cross-link and three models with a cross-link at three different sites. The peak von Mises stress (PVMS) of the rod around the PSO site was measured after applying physiological loads (flexion, extension, axial rotation, and lateral bending) in each model.
The measured PVMS outcomes at the PSO site were 135.8, 135.9, 208.9, and 384.7 MPa for model 1, 2, 3, and 4 during flexion, and 180.0, 180.1, 210.1, and 445.7 MPa during extension. These results show that when the cross-link is located at the PSO site, the rod stress at the PSO site increases significantly during flexion and extension. As the cross-link moved away from the PSO site, the effect on the rod stress decreased. When the cross-link was placed two levels away from the PSO site, the rod stress was scarcely affected.
When the cross-link during PSO surgery was positioned two levels away from the PSO site, the risk of rod fracture did not increase.
本研究旨在通过有限元模型（FEM）研究椎弓根切除截骨术（PSO）中交联位置对棒断裂现象的影响。
使用 65 岁女性患者的 CT 数据构建了矢状位失衡腰椎的三维有限元模型。在模拟标准 L4 水平的 PSO 后，我们构建了四个模型，分别为无交联模型和三个交联位置不同的模型。在每个模型中施加生理负荷（屈伸、轴向旋转和侧屈）后，测量 PSO 部位周围棒的最大 von Mises 应力（PVMS）。
在屈伸运动中，模型 1、2、3 和 4 的 PSO 部位的测量 PVMS 结果分别为 135.8、135.9、208.9 和 384.7 MPa；在伸展运动中，模型 1、2、3 和 4 的测量 PVMS 结果分别为 180.0、180.1、210.1 和 445.7 MPa。结果表明，当交联位于 PSO 部位时，在屈伸过程中，PSO 部位的棒的应力显著增加。随着交联远离 PSO 部位，对棒的应力的影响减小。当交联放置在远离 PSO 部位两个节段时，棒的应力几乎不受影响。
当 PSO 手术中的交联位于远离 PSO 部位两个节段时，不会增加棒断裂的风险。
