Wu Li, Jiang Xiaoxuan, Guan Tianmin, He Zhong, Li Jian
Institute of Mechanical Engineering, Dalian Jiaotong University, Dalian, 116028, Liaoning, China.
Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing, 210009, Jiangsu, China.
Heliyon. 2024 Oct 4;10(19):e38929. doi: 10.1016/j.heliyon.2024.e38929. eCollection 2024 Oct 15.
An alternative to conventional posterior lumbar interbody fusion (PLIF) is a PLIF with transpedicular oblique screw fixation system. An assessment of new fixation system's viability and efficacy is conducted through a comparison of its biomechanical properties with those of conventional PLIF.
A comprehensive finite element model (FEM) of the lumbar regions L1-L5 was developed and the surgical segment L3-L4 was chosen to comprise the surgical models of both traditional PLIF and new PLIF. In new PLIF model, an analysis was conducted on segmental range of motion (RoM), cage stress, inferior endplates stress, vertebral stress, and internal fixation stress. Three-dimensional printers are utilized to fabricate and assemble the fusion cage and vertebrae, and compression test machines are employed to execute physiological load and extreme load experiments on new PLIF, so as to verify the accuracy of the FEM analysis and the mode of fatigue exhibited by new PLIF.
In new PLIF, the maximum stress on the inferior endplates under physiological loads was reduced in comparison to conventional PLIF. While the maximum stress on the cage, vertebral body, and screw increased, it remained within an acceptable range. The experimental data indicates that new fixation system can endure a vertical load exceeding 2800 N and an ultimate bending moment of 77 Nm.
The new PLIF exhibits a comparable RoM to its predecessor, simultaneously mitigating inferior endplate stress and accommodating physiological loads, which reduce the amount of surgical incision and fusion fixation instruments. Consequently, it emerges as a sanguine surgical approach to fuse the degenerative lumbar spine.
传统后路腰椎椎间融合术（PLIF）的一种替代方法是采用经椎弓根斜向螺钉固定系统的PLIF。通过将新固定系统的生物力学特性与传统PLIF的生物力学特性进行比较，对其可行性和有效性进行评估。
建立了L1-L5腰椎区域的综合有限元模型（FEM），并选择手术节段L3-L4构建传统PLIF和新型PLIF的手术模型。在新型PLIF模型中，对节段活动度（RoM）、椎间融合器应力、下终板应力、椎体应力和内固定应力进行了分析。利用三维打印机制作并组装融合器和椎体，并使用压缩试验机对新型PLIF进行生理负荷和极限负荷实验，以验证有限元分析的准确性以及新型PLIF的疲劳模式。
在新型PLIF中，与传统PLIF相比，生理负荷下下终板的最大应力降低。虽然椎间融合器、椎体和螺钉上的最大应力有所增加，但仍在可接受范围内。实验数据表明，新固定系统能够承受超过2800 N的垂直负荷和77 Nm的极限弯矩。
新型PLIF的活动度与传统PLIF相当，同时减轻了下终板应力并能承受生理负荷，减少了手术切口和融合固定器械的数量。因此，它成为一种治疗退行性腰椎疾病的有前景的手术方法。
