斜外侧椎间融合结合不同内固定方式治疗退变性腰椎侧凸的有限元分析

目的 运用三维有限元分析法验证斜外侧椎间融合(oblique lateral interbody fusion, OLIF)辅助不同内固定方式治疗退变性腰椎侧凸(degenerative lumbar scoliosis, DLS)的生物力学稳定性。方法 建立L1～S1三维有限元DLS模型(模型1),模拟L2～5连续三节段OLIF手术及其结合不同内固定方式，分别建立单纯OLIF(stand-alone OLIF)模型(模型2)、椎体钉棒固定模型(模型3)、单边椎弓根螺钉固定模型(模型4)和双边椎弓根螺钉固定模型(模型5)。在直立、前屈、后伸、左右侧弯、左右旋转工况下，记录并分析各模型融合节段活动度(range of motion, ROM)、融合器及内固定的应力及其分布情况。结果 6种运动工况下，模型2～5融合节段整体ROM均小于模型1;与模型1相比，模型3、4的ROM降幅大于模型2、小于模型5;前屈和后伸工况下，模型4与模型5的ROM降幅相仿；左右侧弯工况下，模型3与模型5的ROM降幅相仿。在所有运动工况下，模型3、4融合器应力峰值大于模型5、小于模型2;其中，模型3的L2～3、L3...

Biomechanical Evaluation of Oblique Lateral Interbody Fusion Combined with Different Internal Fixation Methods for Treating Degenerative Lumbar Scoliosis:A Finite Element Analysis

Objective To verify the biomechanical stability of oblique lateral interbody fusion ( OLIF) combinedwith different fixation methods for treating degenerative lumbar scoliosis (DLS) by three-dimensional (3D) finite element analysis. Methods The L1-S1 3D finite element DLS model ( Model 1) was established, and then the OLIF (L2-5) at 3 contiguous levels of fusion and its combination with different internal fixation methods were simulated, namely, stand-alone OLIF model ( Model 2), vertebral screw fixation model ( Model 3), unilateral pedicle screw fixation model (Model 4) and bilateral pedicle screw fixation model (Model 5) were established,respectively. Under upright, flexion, extension, lateral bending and axial rotation states, range of motion (ROM) of fusion segments, as well as cage stress, internal fixation stress, and stress distribution were recorded and analyzed. Results Under six motion states, the overall ROM of fusion segments in Models 2-5 was smaller than that of Model 1. Compared with Model 1, the overall ROM reduction of Model 3 and Model 4 was larger than that of Model 2 and smaller than that of Model 5. Under flexion and extension, the overall ROM reduction of Model 4 and Model 5 was basically equal. Under left and right lateral bending, the overall ROM reduction of Model 3 and Model 5 was basically equal. Under all motion states, the peak stress of Model 3 and Model 4 fusion cage was larger than that of Model 5 and smaller than that of Model 2. The peak stresses of L2-3, L3-4 and L4-5 fusion cages in Model 3 increased by 5. 52% , 10. 96% and 7. 99% respectively compared with Model 5 under left lateral bending, and the peak stresses of L2-3, L3-4 and L4-5 fusion cages in Model 4 increased by 8. 70% , 7. 00% and 6. 99% respectively under flexion. Under all motion states, the peak stress of screw rod in Model 5 was smaller than that of Model 3 and Model 4, and the peak stresses of screw rod in Models 3-5 were the smallest in upright state. Conclusions The OLIF with unilateral pedicle screw fixation or vertebral screw fixation can provide favorable biomechanical stability of the fusion segment. The results provide some references for clinical application of OLIF technology in the treatment of DLS.