In Vitro Study of Biomechanical Analysis of Modified Lateral Lumbar Interbody Fusion—crenel Lumbar Interbody Fusion

Background: To analyze the biomechanical stability of the modified LLIF, crenel lateral interbody fusion (CLIF), and compare various methods of instrumentation of CLIF in vitro. Methods: Three fresh-frozen cadaveric lumbar spines (L1-S1) were used in our study. The modified CLIF interbody cage was inserted into the L3/4 level in each specimen. Every specimen was tested under 5 conditions: intact group; stand-alone CLIF group; CLIF with lateral plate group (CLIF + LP); CLIF with lateral plate and unilateral pedicle screw group (CLIF + LP + UPS); CLIF with bilateral pedicle screw group (CLIF + BPS). Results: The ROM of each CLIF group was significantly reduced when compared with intact group in all directions of loading (p< 0.05). The CLIF + LP + BPS group was the most stable in all directions of loading. CLIF + LP group has less ROM when compared with stand-alone group except for the extension condition. CLIF + BPS group has less ROM than CLIF + LP group in every condition. Conclusions: CLIF combine with lateral plate and bilateral pedicel screw is the most stable supplemental fixation, and lateral plate could reduce the ROM under rotation and lateral bending conditions. For patients with good bone quality, stand-alone with or without is a alternative method to achieve a good clinical result.