Postdoctoral Fellow Vanderbilt University Medical Center
Introduction: Understanding the impact of spondylolisthesis reduction on outcomes remains an active research area, with newer techniques potentially enabling safer reductions. We aimed to evaluate the effect of spondylolisthesis reduction on 1) reoperation rates, 2) patient-reported outcomes (PROMs), and 3) need for spinal injections in patients undergoing primary, single-level lumbar decompression and fusion for grade I-II spondylolisthesis.
Methods: This single-institution, retrospective cohort study included patients undergoing primary single-level lumbar decompression and fusion for spondylolisthesis from 2010-2021. Primary exposure was spondylolisthesis reduction (≥2 mm) and segmental lordosis improvement (≥5°), with the primary outcome was long-term reoperation and secondary outcomes including 2-year PROMs. Descriptive and multivariable analyses were performed.
Results:
Results: In a cohort of 339 patients undergoing single-level lumbar decompression and fusion for spondylolisthesis, with a mean follow up was 6 years, 90% had grade I spondylolisthesis, and 65.5% received interbody fusion. Spondylolisthesis reduction: A 2 mm reduction was seen in 161 (47.5%) patients. Complete reduction occurred in only 16 (4.7%) patients. Reoperation rates were similar between those with and without reduction (12.4% vs. 11.8%, p=0.860) and complete reduction or not (12.5% vs. 12.0%, p=0.599). Spondylolisthesis reduction was not significantly associated with the need for spinal injections (31.4% vs 25.8%, p = 0.615) or PROMs including MCID of ODI or NRS-back/leg pain (all p>0.05) at two years or at long-term follow-up. Segmental lordosis: Mean postoperative segmental lordosis was 19.6±8.1º and 118 (34.8%) had improvement by at least 5°. No difference in the rate of reoperation (10.2% vs 13.1%, p=0.427), need for spinal injections (35% vs 26.1%, p=0.462) or PROMs (all p>0.05) was seen in patients with improved segmental lordosis or not. Multivariable regression confirmed the lack of significant differences across these outcomes.
Conclusion : In patients undergoing elective, primary, single-level lumbar decompression and fusion for spondylolisthesis, reduction in spondylolisthesis was seen in half of the patients, though only 5% had a complete reduction. No significant difference was found in spondylolisthesis reduction or slip angle and long-term reoperation, PROMs, and spinal injections. These findings speak to the complexity of treating spondylolisthesis to maximize long-term outcomes and the need for future research regarding this common condition.