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Updated: Apr 7, 2026
Multilevel Oblique Lumbar Interbody Fusion in Degenerative Lumbar Disc Disease with Instability
Published on: July 25, 2025
Biomechanical evaluation of a novel L-shaped side-locking plate combined with OLIF: a finite element analysis
Zemin Wang1, Lijun Wang2, Honglai Zhang1
1First Clinical Medical College, Ningxia Medical University, Yinchuan, China.
Background:
Oblique lateral interbody fusion (OLIF) is a minimally invasive technique widely used for lumbar degenerative diseases. However, high rates of cage subsidence, particularly in osteoporotic bone, necessitate supplemental fixation. Traditional bilateral pedicle screw (BPS) fixation compromises OLIF's minimally invasive advantages, while conventional lateral plates provide limited stability in the sagittal plane. To address these limitations, we developed and evaluated a novel L-shaped side-locking plate (NLSLP) using finite element analysis.
Methods:
A validated L3-S1 finite element model was adapted to simulate L4/5 OLIF. Four surgical models were constructed: stand-alone (SA) OLIF, OLIF with a two-screw lateral plate (LP-2), OLIF with bilateral pedicle screws (BPS), and OLIF with the NLSLP. Three bone density conditions-normal bone density (NBD), osteopenia, and osteoporosis-were modeled to evaluate the biomechanical performance of each configuration. The range of motion (ROM), stress distribution in the endplates, adjacent intervertebral discs, and internal fixation were analyzed under vertical load (400 N) and torque (7.5 N·m).
Results:
All NLSLP configurations significantly reduced ROM at the L4-L5 segment, with lateral bending and axial rotation reductions exceeding 85%, and flexion-extension reductions of 85.84% and 75.01% for the NLSLP-d model. Compared to LP-2, the NLSLP system provided 17.85%-18.22% greater restriction in sagittal plane motion. In osteoporotic models, the NLSLP still maintained biomechanical stability, with ROM reduction exceeding 65%. Increased stress in adjacent intervertebral discs was observed in all surgical models, with the NLSLP showing a 39.86%-45.12% increase in lateral bending stress. Stress on the L5 superior endplate was reduced across all loading conditions in the NLSLP model compared to the SA model, thus reducing the risk of endplate damage and cage subsidence. Internal fixation stress remained well below the material fatigue and yield strength, indicating favorable stress distribution in NLSLP.
Conclusions:
The NLSLP represents a viable adjunctive fixation option for OLIF, offering superior sagittal plane stability compared to LP-2 while retaining the minimally invasive and single-position advantages of the OLIF procedure.
