Effect of Supplemental Fixation on Fusion and Subsidence After Lateral Lumbar Interbody Fusion

Background Lateral lumbar interbody fusion (LLIF) is currently popularized as an effective and safe approach to attain a lumbar fusion. The effect that supplemental fixation plays on fusion and subsidence rates after lateral lumbar surgery remains understudied. This study aims to directly compare fusion rates and subsidence rates in patients undergoing single-level lateral lumbar surgery with and without supplemental fixation for the treatment of degenerative disc disease with or without spondylolisthesis. Methods We included all single-level lateral interbody procedures for degenerative disc disease with or without spondylolisthesis. We excluded adult spinal deformity, infections, trauma, neoplastic pathology, and patients undergoing lateral interbody fusion of more than one level. Basic demographic data, lumbar lordosis, subsidence rates, and fusion rates were measured across the two groups. Results Forty-five (54.2%) patients underwent interbody placement alone without posterior supplemental fixation, while thirty-eight (45.8%) patients underwent percutaneous pedicle screw placement in addition to interbody placement. Only two patients underwent interbody placement at L1-2, none of whom received posterior fixation. Also, there was no significant difference in the mean change in lumbar lordosis (LL) angle between both groups (p=0.7). Furthermore, there was no significant difference in terms of the fusion (p=0.5) and subsidence (p=0.4) grades between both groups. The operative time was significantly longer in the supplemented fixation group (P<0.001). However, there was no significant difference in the hospital stay between both groups (p=0.7). Conclusion Supplemental fixation did not significantly affect fusion or subsidence rates in this study. Further studies are warranted to verify the results of this study.