Finite element assessment of the biomechanical implications of various internal fixation techniques used in lumbar interbody fusion surgeries

Abstract The use of lumbar interbody fusion along with an internal fixation device is a common procedure for addressing conditions such as herniated lumbar discs and lumbar spondylolisthesis. As there are fewer comparative studies on the posterior lateral approach, this study can provide a reference for a new surgical approach and a more optimized fixation protocol for the patient; hence, the following study is done. Accurate reconstruction of vertebral geometry and simulation of soft tissues enables the simulation of the implant’s positioning and configuration, as well as its impact on the surrounding tissues, throughout the surgical procedure. The fixation stage and intervertebral stresses, the disc stresses in neighboring segments, and the differences in mobility between stages were compared separately in each model. The total lumbar spine activity during forward flexion, backward extension, lateral bending, and twisting was reduced in Groups A, B, C, and D compared to the intact model. In addition, Group A generally had the least range of motion. As a result, patients in Group A had a more stable spine with a lower likelihood of degeneration.