Zhao Xin, Du Lin, Xie Youzhuan, Zhao Jie
Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China.
World Neurosurg. 2018 Jun;114:e114-e120. doi: 10.1016/j.wneu.2018.02.073. Epub 2018 Feb 21.
We used a finite element (FE) analysis to investigate the biomechanical changes caused by transforaminal lumbar interbody fusion (TLIF) at the L4-L5 level by lumbar lordosis (LL) degree.
A lumbar FE model (L1-S5) was constructed based on computed tomography scans of a 30-year-old healthy male volunteer (pelvic incidence,= 50°; LL, 52°). We investigated the influence of LL on the biomechanical behavior of the lumbar spine after TLIF in L4-L5 fusion models with 57°, 52°, 47°, and 40° LL. The LL was defined as the angle between the superior end plate of L1 and the superior end plate of S1. A 150-N vertical axial preload was imposed on the superior surface of L3. A 10-N/m moment was simultaneously applied on the L3 superior surface along the radial direction to simulate the 4 basic physiologic motions of flexion, extension, lateral bending, and torsion in the numeric simulations. The range of motion (ROM) and intradiscal pressure (IDP) of L3-L4 were evaluated and compared in the simulated cases.
In all motion patterns, the ROM and IDP were both increased after TLIF. In addition, the decrease in lordosis generally increased the ROM and IDP in all motion patterns.
This FE analysis indicated that decreased spinal lordosis may evoke overstress of the adjacent segment and increase the risk of the pathologic development of adjacent segment degeneration; thus, adjacent segment degeneration should be considered when planning a spinal fusion procedure.
我们采用有限元（FE）分析，以研究L4 - L5节段经椎间孔腰椎椎间融合术（TLIF）因腰椎前凸（LL）程度不同而引起的生物力学变化。
基于一名30岁健康男性志愿者的计算机断层扫描构建腰椎有限元模型（L1 - S5）（骨盆入射角 = 50°；LL，52°）。我们研究了LL对LL分别为57°、52°、47°和40°的L4 - L5融合模型中TLIF术后腰椎生物力学行为的影响。LL定义为L1上终板与S1上终板之间的角度。在L3上表面施加150 N的垂直轴向预载荷。同时沿径向在L3上表面施加10 N/m的力矩，以在数值模拟中模拟屈曲、伸展、侧弯和扭转这4种基本生理运动。评估并比较模拟病例中L3 - L4的活动度（ROM）和椎间盘内压力（IDP）。
在所有运动模式下，TLIF术后ROM和IDP均增加。此外，前凸的减小通常会使所有运动模式下的ROM和IDP增加。
该有限元分析表明，脊柱前凸减小可能会引发相邻节段的应力过载，并增加相邻节段退变病理发展风险；因此，在规划脊柱融合手术时应考虑相邻节段退变。
