南方医科大学学报

南方医科大学学报 ›› 2023, Vol. 43 ›› Issue (3): 331-339.doi: 10.12122/j.issn.1673-4254.2023.03.01

• •    下一篇

钢板内固定系统重建椎管的生物力学分析

陈建民，刘国印，包天翼，柏天婷，张二来，赵建宁   

  1. 南京医科大学金陵临床医学院骨科，江苏 南京 210002；厦门医疗器械研发检测中心有限公司，福建 厦门 361027
  • 出版日期:2023-03-20 发布日期:2023-03-20

Biomechanical analysis of miniplate fixation systems in restorative laminoplasty for spinal canal reconstruction

CHEN Jianmin, LIU Guoyin, BAO Tianyi, BAI Tianting, ZHANG Erlai, ZHAO Jianning   

  1. Department of Orthopedics, Jinling Hospital of Nanjing Medical University, Nanjing 210002, China; Xiamen Medical Device Testing and Research Co., Ltd, Xiamen 361022, China
  • Online:2023-03-20 Published:2023-03-20

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摘要： 目的 比较椎板切除回植后应用不同钢板内固定系统（微H钢板和微L钢板）重建椎管的生物力学性能。方法 应用3D打印技术打造正常腰4（L4）椎体模型，对L4椎体模型实施全椎板切除，根据椎板回植椎管重建 (RL-SCR) 内固定方式的不同分成微H钢板（H-MFS）组和微L钢板（L-MFS）组；分别通过静态压缩和动态疲劳压缩实验对两组RL-SCR模型进行加载直至钢板失效、断裂或回植椎板塌陷；静态压缩实验采用速度控制模式，动态疲劳压缩实验采用载荷控制模式。同时，通过建立正常L3-L5有限元模型，在验证该模型有效性的前提下进行RL-SCR的生物力学研究；根据处理方式不同分为正常赋值组、椎板切除组、H-MFS组和L-MFS组；在相同载荷下，模拟前屈、后伸、左弯、右弯、左旋和右旋6个方向的生理活动条件，对各组L3-L4和L4-L5的活动度 (ROM)变化进行评估。结果 RL-SCR静态压缩实验中，H-MFS组的持续屈服载荷大于L-MFS组（P<0.05），在相同机械载荷下的压缩刚度、屈服位移和轴向位移-轴向载荷排列为：H-MFS组>L-MFS组（P<0.05）；L-MFS组全部出现椎板原位还纳或“闭门”现象及椎板塌陷，均出现钢板断裂现象；而H-MFS组未出现钢板断裂现象，仅部分出现螺钉周围的钢板裂纹和螺钉尾帽松动的现象；RL-SCR的动态压缩疲劳实验中，H-MFS组的动态压缩峰值载荷可达 873 N，为静压缩平均屈服载荷的 95%，优于L-MFS组（P<0.05）；而 L-MFS组的动态压缩峰值荷载仅为 468 N，为静压缩平均屈服载荷的80%；此外，根据疲劳寿命-峰值载荷图估算出L-MFS组的极限载荷仅为H-MFS组的46.59%，差异有统计学意义（P<0.05）。与椎板切除组相比，6种加载工况下，正常赋值组、H-MFS组和L-MFS组L3-L4和L4-L5的ROM范围均明显降低；与正常赋值组相比，H-MFS组仅在后伸时的ROM增加明显，而L-MFS组在前屈、后伸、左旋和右旋时的ROM增加明显；病变节段ROM的整体趋势为椎板切除组>L-MFS组>H-MFS组>正常赋值组。结论 椎板切除会破坏脊柱后柱结构，从而影响其生物力学稳定性，而应用RL-SCR内固定的方式可有效维持脊柱生物力学的稳定性，且与微L钢板相比，微H钢板在维持椎管完整性和生物力学性能上的优势更明显。

关键词: 椎板回植椎管重建；椎板钢板；3D打印；静态压缩；动态压缩；生物力学；有限元分析

Abstract: Objective To investigate the biomechanical properties of H-shaped and L-shaped miniplate fixation systems (H-MFS and L-MFS, respectively) in restorative laminoplasty for spinal canal reconstruction (RL-SCR). Methods Laminectomy was performed in a 3D printed L4 vertebral model followed by RL-SCR using H-MFS or L-MFS, and the biomechanical properties of the reconstructed models were evaluated using static and dynamic compression tests. Biomechanical analyses of RL-SCR were also conducted in finite element models of the L3-L5 vertebrae with normal assignment (NA), laminectomy, or fixation with H-MFS or L-MFS, and the range of motion (ROM) of L3-L4 and L4-L5 was evaluated. Results In static compression test, the sustained yield load, compression stiffness, yield displacement and axial displacement- axial load were all significantly greater in H-MFS group (P<0.05). Door closing, lamina collapse and plate breakage occurred in all the models in L-MFS group, and only some models in H-MFS group showed plate cracks and screw loosening. In dynamic compression tests, the peak load in H-MFS group reached 873 N (which was 95% of the average yield load in static compression), significantly greater than that in L-MFS group (P<0.05). The ultimate load in L-MFS group was only 46.59% of that in H-MFS group (P>0.05). In finite element analysis, the ROM of the L3-L4 and L4- L5 segments were significantly smaller in NA, H-MFS and L-MFS groups than in laminectomy group. Compared with NA group, H-MFS group showed a greater ROM during extension, and L-MFS group showed greater ROM in flexion, extension, bending, and rotation; The overall ROM of the vertebral segments decreased in the order of laminectomy group, L-MFS group, H-MFS group, and NA group. Conclusion Laminectomy causes structural destruction of the posterior column of the spine to affect its biomechanical stability. RL-SCR can effectively maintain the biomechanical stability of the spine, and H-MFS is superior to L-MFS in maintaining the integrity and biomechanical properties of the reconstructed spinal canal.

Key words: restorative laminoplasty for spinal canal reconstruction; lamina replantation; three-dimensional printing; static compression; dynamic compression; biomechanics; finite element analysis