Biomechanical advances in oblique lateral lumbar interbody fusion using different interbody cages

Oblique lateral lumbar interbody fusion (OLIF) is a minimally invasive spinal fusion technique that has gained increasing popularity in the treatment of lumbar degenerative diseases. The interbody cage is a critical implant in OLIF procedures, and its material properties, structural design, dimensions, placement location, and combination with supplemental fixation strategies play a decisive role in determining immediate postoperative stability, fusion rate, restoration of disc height and lumbar lordosis, stress distribution, and the risk of adjacent segment degeneration (ASD). This review aims to summarize recent biomechanical research advances on OLIF combined with different interbody cages, to critically evaluate the advantages and limitations of various cage designs, and to analyze the effects of different fixation strategies on postoperative biomechanical performance. By comparing the biomechanical characteristics of polyetheretherketone, titanium alloy, novel biodegradable, and composite cages, and integrating evidence from finite element analyses, in vitro biomechanical experiments, and clinical studies, this review elucidates their differences in providing spinal stability, promoting osseous fusion, and reducing postoperative complications. In addition, this article highlights the biomechanical impact of cage placement, size, and geometry, and explores how topological optimization and patient-specific design may further enhance cage performance. Drawing on successful experiences with interbody cage designs in cervical fusion surgery, future directions for lumbar interbody cages are discussed, including integrated structural design, material innovation, and personalized customization, with the goal of providing optimized surgical strategies and implant selection for clinical practice.