基于三维有限元分析不同滑脱程度的腰椎峡部裂原位融合术后相邻节段的生物力学变化OA

Aim To explore the biomechanical effects of in situ fusion on adjacent segments in patients with lumbar spon-dylolytic true spondylolisthesis of varying degrees.Methods Lumbar spondylolisthesis in situ fusion and fixation models(reset fixed model,Ⅰ degree slip in situ fixation model,Ⅱ degree slip in situ fixation model,Ⅲ degree slip in situ fixation model)of lum-bar(L)4/sacral(S)1 with different degrees of slippage were established based on three-dimensional finite element.The activity of each model and the stress distribution of intervertebral discs and facet joints in adjacent L4/5 segments were compared.Results Compared with the reset fixed model,there was no significant change in the activity and stress of the L4/5 segment in Ⅰ degree slip in situ fixation model;The L4/5 segment of the Ⅱ degree slip in situ fixation model showed a relative increase in range of motion and in-creased stress on the annulus fibrosus and articular surface;The Ⅲ degree slip in situ fixation model showed abnormal L4/5 segment mobility and decreased stress on the fibrous ring and joint surface.Conclusion The biomechanical effects of in situ fixation for lumbar spondylolisthesis have a graded dependence:grade Ⅰ spondylolisthesis has a lower risk of adjacent segment degeneration(ASD)after in situ fixation;Attention should be paid to the risk of ASD occurrence in cases of grade Ⅱ slippage;Grade Ⅲ spondylo-listhesis should be prioritized to reduction and fusion to restore spinal stability.