Hybrid pedicle screw and modified cortical bone trajectory technique in transforaminal lumbar interbody fusion at L4-L5 segment: finite element analysis

Abstract

Background Investigate the biomechanical properties of the hybrid fixation technique with bilateral pedicle screw (BPS) and bilateral modified cortical bone trajectory screw (BMCS) in L4-L5 transforaminal lumbar interbody fusion (TLIF). Methods Three finite element (FE) models of the L1-S1 lumbar spine were established according to the three human cadaveric lumbar specimens. BPS-BMCS (BPS at L4 and BMCS at L5), BMCS-BPS (BMCS at L4 and BPS at L5), BPS-BPS (BPS at L4 and L5), and BMCS-BMCS (BMCS at L4 and L5) were implanted into the L4-L5 segment of each FE model. The range of motion (ROM) of the L4-L5 segment, von Mises stress of the fixation, intervertebral cage, and rod were compared under a 400-N compressive load with 7.5 Nm moments in flexion, extension, bending, and rotation. Results BPS-BMCS technique has the lowest ROM in extension and rotation, and BMCS-BMCS technique has the lowest ROM in flexion and lateral bending. The BMCS-BMCS technique showed maximal cage stress in flexion and lateral bending, and the BPS-BPS technique in extension and rotation. Compared to the BPS-BPS and BMCS-BMCS technique, BPS-BMCS technique presented a lower risk of screw breakage and BMCS-BPS technique presented a lower risk of rod breakage. Conclusion The results of this study support that the use of the BPS-BMCS and BMCS-BPS techniques in TLIF surgery for offering the superior stability and a lower risk of cage subsidence and instrument-related complication.

Finite element analysis of endoscopic cross-overtop decompression for single-segment lumbar spinal stenosis based on real clinical cases

“…Once all properties were configured, the standard structure model M0 was generated. Table 1 shows the material parameters of the model components according to the material properties of the spinal structures based on the literature ( Cao et al, 2020 ; Kahaer et al, 2023 ).…”

Comparative Biomechanical Stability of the Fixation of Different Miniplates in Restorative Laminoplasty after Laminectomy: A Finite Element Study

“…The contact types were set according to previous studies [34][35][36][37][38]. A 3D surface-tosurface sliding contact with friction was specified to simulate the joints' contact behavior with a finite sliding interaction defined to allow random motions, including sliding, rotation, and separation.…”

“…In the interaction settings, cortical bone was bound to cancellous bone, and ligaments were bound to the outer surface of cortical bone. The contact between facet joints was defined as nonlinear, surface-to-surface, frictionless sliding contact [34,38]. The contact between vertebra and IVDs was designated as mutual contact with a friction coefficient of 0.08 [37].…”