Is it Necessary to Fuse? A Propensity Score-Matched Analysis of One- Versus Two-Level Fusions With Multilevel Decompression

Study Design Retrospective cohort study. Objective In patients with multilevel degenerative lumbar pathology, the decision to extend fusion across all decompressed levels remains a subject of debate. While fusion provides stability in cases of instability or deformity, its necessity for adjacent levels without specific fusion indications is unclear. This study evaluates whether decompression alone at levels without clear fusion indications can achieve similar outcomes compared to spanning the entire decompression with fusion. Methods The present study is a retrospective cohort study. Patients who underwent one-level decompression and fusion with 2 level decompression (SLF) were propensity score matched with patients who underwent two-level decompression and fusion (DLF) for degenerative conditions of the lumbar spine. Patient-reported outcome measures (PROMs), complication rates, revision surgeries, and recovery kinetics were compared between the cohorts. Results After propensity score matching a total of 43 SLF patients were compared with 43 DLF patients. Early follow-up (<6 months) showed significantly higher SF-12 PCS scores in the SLF group ( P = .042) and greater achievement of VAS-leg MCID (88.9% vs 59.4%, P = .012). Long-term outcomes (≥6 months) demonstrated no significant differences in ODI, VAS-back, VAS-leg, or SF-12 PCS scores between groups. There were no differences in intraoperative or perioperative complications. The postoperative complication rate was significantly higher in the DLF group (25.6% vs 7%, P = .019) including 4 DLF patients that underwent revision surgery while no SLF patients required revision during their follow up time. Conclusion SLF resulted in similar long-term outcomes compared to DLF with fewer revisions and adjacent segment symptoms. These findings suggest that “saving” a fusion level in cases without a specific fusion indication at the adjacent level may be warranted to optimize longevity of the construct. Further research is necessary to refine patient selection for fusion levels in degenerative lumbar disease.