Dhar Utpal K, Sultan Hadi, Aghayev Kamran, Tsai Chi-Tay, Vrionis Frank D
Department of Ocean and Mechanical Engineering, Florida Atlantic University, Boca Raton, FL, United States.
Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, FL, United States.
Front Bioeng Biotechnol. 2024 Nov 28;12:1491420. doi: 10.3389/fbioe.2024.1491420. eCollection 2024.
Limited information regarding the biomechanical evaluation of various internal fixation techniques for high-grade L5-S1 spondylolisthesis is available. The stiffness of the operated segment and stress on the hardware can profoundly influence clinical outcomes and patient satisfaction. The objective of this study was to quantitatively investigate biomechanical profiles of various fusion methods used for high-grade spondylolisthesis by using finite element (FE) analysis.
An FE lumbar spine model of healthy spine was developed based on a patient's CT scan. High-grade (III-IV) spondylolisthesis (SP model) was created by sliding L5 anteriorly and modifying L5-S1 facet joints. Three treatment scenarios were created by adding various implants to the model. These scenarios included L5-S1 interbody cage in combination with three different fixation methods-the anterior plate system (APS), bilateral pedicle screw system (BPSS), and transdiscal screw system (TSS). Range of motion (ROM), von Mises stress on cage, internal fixation as well as on the adjacent annuli were obtained and compared. The resistance to slippage was investigated by applying shear force on L5 vertebra and measuring its displacement regarding to S1.
Under different loading conditions all treatment scenarios showed substantial reduction of ROM in comparison with SP model. No notable differences in ROM were observed between treatment models. There was no notable difference in cage stress among models. The von Mises stress on the internal fixation in the TSS model was less than in APS and BPSS. The TSS model demonstrated superior resistance to shear load compared to APS and BPSS. No discernible difference was observed between the SP, APS, BPSS, and TSS models when compared the ROM for adjacent level L4-L5. TSS's von Mises stress of the adjacent annulus was higher than in APS and BPSS.
The TSS model exhibited biomechanical superiority over the APS and BPSS models.
关于高级别L5 - S1椎体滑脱各种内固定技术的生物力学评估信息有限。手术节段的刚度和内固定器械上的应力会对临床结果和患者满意度产生深远影响。本研究的目的是通过有限元（FE）分析定量研究用于高级别椎体滑脱的各种融合方法的生物力学特征。
基于患者的CT扫描建立健康脊柱的有限元腰椎模型。通过将L5向前滑动并修改L5 - S1小关节来创建高级别（III - IV级）椎体滑脱（SP模型）。通过向模型中添加各种植入物创建三种治疗方案。这些方案包括L5 - S1椎间融合器结合三种不同的固定方法——前路钢板系统（APS）、双侧椎弓根螺钉系统（BPSS）和经椎间盘螺钉系统（TSS）。获得并比较了活动范围（ROM）、融合器上的von Mises应力、内固定以及相邻椎间盘环上的应力。通过对L5椎体施加剪切力并测量其相对于S1的位移来研究抗滑移能力。
在不同加载条件下，与SP模型相比，所有治疗方案的ROM均显著降低。各治疗模型之间在ROM方面未观察到显著差异。各模型之间融合器应力无显著差异。TSS模型中内固定上的von Mises应力低于APS和BPSS模型。与APS和BPSS相比，TSS模型表现出更好的抗剪切载荷能力。当比较相邻节段L4 - L5的ROM时，SP、APS、BPSS和TSS模型之间未观察到明显差异。TSS模型中相邻椎间盘环的von Mises应力高于APS和BPSS模型。
TSS模型在生物力学方面优于APS和BPSS模型。
