MIS-TLIF中Cage置入角度对内固定应力及邻近椎间盘力学影响的有限元分析OA

Objective To investigate the biomechanical effects of different cage insertion angles during minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF)on internal fixation stability and adjacent intervertebral discs using three-dimensional finite element analysis,and to provide recommendations for optimal clinical practice.Methods A three-dimensional finite element model of the L3-S1 lumbar spine was reconstructed from CT imaging data.MIS-TLIF was simulated at the L4/5 segment,with the interbody cage inserted at the sagittal midline and tilted horizontally at 0°,15°,30°,and 45°,defined as groups A,B,C,and D,respectively.A compressive load of 500 N and a torque of 10 N·m were applied to each model to simulate lumbar motions(flexion,extension,lateral bending,and axial rotation).Range of motion(ROM),stress distribution on pedicle screws and cages,and stress changes in adjacent discs(L3/4,L5/S1)were analyzed.Results Compared with the intact model,all fusion models(A-D)showed a significant reduction in ROM across all motion states,with little difference among insertion angles.As the cage insertion angle increased,cage stress gradually rose,whereas the stress on the fixation system decreased.Meanwhile,disc stress at adjacent segments(L3/4,L5/S1)also increased with larger insertion angles.Conclusion Insertion of cages at different inclination angles during MIS-TLIF effectively reduces the range of motion(ROM)of the operated segment and enhances stability.As the insertion angle increases,cage stress rises,screw-rod system stress shows a slight decrease,and adjacent intervertebral disc stress increases accordingly.Considering segmental stability,load distribution,and adjacent segment loading,transverse(0°)insertion is recommended to achieve an optimal biomechanical balance and long-term risk control.