Oblique lateral interbody fusion combined with different internal fixations for the treatment of degenerative lumbar spine disease: a finite element analysis

Abstract

Background Little is known about the biomechanical performance of different internal fixations in oblique lumbar interbody fusion (OLIF). Here, finite element (FE) analysis was used to describe the biomechanics of various internal fixations and compare and explore the stability of each fixation. Methods CT scans of a patient with lumbar degenerative disease were performed, and the l3-S1 model was constructed using relevant software. The other five FE models were constructed by simulating the model operation and adding different related implants, including (1) an intact model, (2) a stand-alone (SA) model with no instrument, (3) a unilateral pedicle screw model (UPS), (4) a unilateral pedicle screw contralateral translaminar facet screw model (UPS-CTFS), (5) a bilateral pedicle screw (BPS) model, and (6) a cortical bone trajectory screw model (CBT). Various motion loads were set by FE software to simulate lumbar vertebral activity. The software was also used to extract the range of motion (ROM) of the surgical segment, CAGE and fixation stress in the different models. Results The SA group had the greatest ROM and CAGE stress. The ROM of the BPS and UPS-CTFS was not significantly different among motion loadings. Compared with the other three models, the BPS model had lower internal fixation stress among loading conditions, and the CBT screw internal fixation had the highest stress among loads. Conclusions The BPS model provided the best biomechanical stability for OLIF. The SA model was relatively less stable. The UPS-CTFS group had reduced ROM in the fusion segments, but the stresses on the internal fixation and CAGE were relatively higher in the than in the BPS group; the CBT group had a lower flexion and extension ROM and higher rotation and lateral flexion ROM than the BPS group. The stability of the CBT group was poorer than that of the BPS and LPS-CTFS groups. The CAGE and internal fixation stress was greater in the CBT group.

Biomechanical comparative analysis of conventional pedicle screws and cortical bone trajectory fixation in the lumbar spine: An in vitro and finite element study

“…According to this study, L34CBT/L45PS is more effective than L3CBT-L45PS and L345PS when ASD develops as a result of single-segment fixation. Zhang et al (2022) came to the conclusion that while the fused segment’s flexion and extension mobility were relatively low in the CBT screw group, its rotational ROM was higher than that of the PS screw, and comparable findings were found in the current investigation. Spinal flexibility is greatly decreased by posterior fixation.…”

Application of the cortical bone trajectory technique in posterior lumbar fixation

“…Oshino et al [ 28 ] concluded that the intervertebral stability after CBT fixation was similar to that after PS fixation. Delgado-Fernandez et al [ 29 ] found that CBT screws exhibit greater stiffness in cephalocaudal and medio-lateral loading, better flexion and extension resistance and better screw-holding stability in the pullout strength than traditional PSs; however, CBT screws were inferior in terms of lateral bending and axial rotation; these findings were confirmed in recent studies[ 24 , 30 - 34 ].…”

Biomechanical characteristics of 2 different posterior fixation methods of bilateral pedicle screws: A finite element analysis

“…[49] Although this difference in stress does not have a decisive impact on the operation, the long-term stress concentration will lead to fracture of pedicle screws due to fatigue, which will bring a series of potential risks after the operation, which is not conducive to the stability of the entire internal fixation system. [50,51]…”