Department of Mechanical Engineering, Tsinghua University, Beijing, China; Biomechanics and Biotechnology Lab, Research Institute of Tsinghua University in Shenzhen, Shenzhen, China.
Naton Science and Technology Group, Beijing, China.
Comput Biol Med. 2018 Apr 1;95:167-174. doi: 10.1016/j.compbiomed.2018.02.016. Epub 2018 Feb 23.
In lumbar interbody fusion, a porous additive manufactured (AM) cage can provide more desirable stiffness, and may be beneficial to bone ingrowth. The biomechanical influence of porous cages on stability, subsidence, and facet contact force has not been fully described. The aim of this study was to verify biomechanical effects of porous cages. A surgical finite element (FE) model of transforaminal lumbar interbody fusion (TLIF) was constructed. Partially porous (PP) cages and fully porous (FP) cages were applied. Mechanical tests were performed to obtain the mechanical parameters of porous materials. The porous cages were compared to solid titanium (TI) cage and solid PEEK cage. Four motion modes were simulated. Range of motion (ROM), cage stress, endplate stress, and facet joint force (FJF) were compared. After interbody fusion, ROM decreased by more than 90% in flexion, bending and rotation. Compared with TI and PP cages, PEEK and FP cages substantially reduced the maximum stresses in cage and endplate in all motion modes. Compared with PEEK cages, the stresses in cage and endplate for FP cages decreased, whereas the ROM increased. Compared among three FP cages, the stresses in cage and endplate decreased with increasing porosity, whereas ROM increased with increasing porosity. FJF for various cages was substantially reduced compared to the intact model in all motion modes except for flexion. In summary, fully porous cages with a porosity of between 65% and 80% may offer an alternative to solid PEEK cages in TLIF.
在腰椎体间融合术中，多孔添加剂制造（AM） cage 可以提供更理想的刚度，并可能有利于骨长入。多孔 cage 对稳定性、下沉和小关节接触力的生物力学影响尚未得到充分描述。本研究旨在验证多孔 cage 的生物力学效应。构建了经椎间孔腰椎体间融合术（TLIF）的手术有限元（FE）模型。应用部分多孔（PP） cage 和全多孔（FP） cage。进行力学测试以获得多孔材料的力学参数。将多孔 cage 与实心钛（TI） cage 和实心聚醚醚酮（PEEK） cage 进行比较。模拟了四种运动模式。比较了运动范围（ROM）、 cage 应力、终板应力和小关节力（FJF）。体间融合后，屈伸和旋转的 ROM 减少了 90%以上。与 TI 和 PP cage 相比，PEEK 和 FP cage 在所有运动模式下均显著降低了 cage 和终板的最大应力。与 PEEK cage 相比，FP cage 的 cage 和终板的应力降低，而 ROM 增加。与三种 FP cage 相比，随着孔隙率的增加， cage 和终板的应力降低，而 ROM 增加。与完整模型相比，除了屈伸运动模式外，各种 cage 的 FJF 在所有运动模式下均显著降低。总之，孔隙率在 65%至 80%之间的全多孔 cage 可能是 TLIF 中实心 PEEK cage 的替代选择。
