Biomechanical effects of transforaminal endoscopic lumbar discectomy combined with spinal dynamic stabilization system use on adjacent segments: a finite element analysis.

Abstract

<h4>Objective</h4>To assess the biomechanical effect of transforaminal endoscopic lumbar discectomy combined with spinal dynamic stabilization system (TELD-SDSS) on the adjacent segments using three-dimensional finite element (3D-FE) analysis, providing reference data for the optimization of surgical approaches for giant lumbar disc herniation (GLDH).<h4>Methods</h4>A 3D-FE model of L3-S1 was constructed based on imaging data and validated against well-established in-vitro biomechanical data. Surgical FE models representing TELD, TELD-SDSS, and posterior lumbar interbody fusion (PLIF) were reconstructed. The risk of adjacent segment degeneration (ASD) was evaluated by comparing adjacent-segment biomechanical parameters under various loading directions using hybrid testing methods.<h4>Results</h4>Compared with the FE model, the PLIF model showed the largest increases in adjacent-segment range of motion, intradiscal pressure, endplate Von Mises stress, and annulus fibrosus shear stress under flexion, extension, lateral bending, and rotational loading. The TELD-SDSS model showed lesser increases, and results for the TELD models did not differ significantly.<h4>Conclusions</h4>The study findings suggest that TELD with limited foraminoplasty and large annuloplasty has no significant impact on the occurrence of ASD. Although TELD-SDSS application alters the biomechanical environment of the adjacent segments, it has potential biomechanical advantages over PLIF in the mitigation of ASD occurrence.