Decompression alone versus decompression with fusion in the treatment of lumbar degenerative spondylolisthesis: evaluating the overlapping meta-analyses

BACKGROUND: Although many meta-analyses have compared decompression alone with decompression combined with fusion for treating lumbar degenerative spondylolisthesis (LDS), their conclusions remain inconsistent. This study aims to analyze these overlapping meta-analyses to provide clinicians with access to the most reliable evidence, thereby enabling informed treatment recommendations for LDS based on the best available data. METHODS: We performed a comprehensive search for relevant meta-analyses published up to December 20, 2025 across PubMed, Embase, Cochrane Library, and Web of Science databases. The methodological quality of these studies was evaluated using A Measurement Tool to Assess Systematic Reviews (AMSTAR) and the Oxford Levels of Evidence. The Jadad decision algorithm was utilized to determine the most credible evidence review. RESULTS: Thirteen meta-analyses were included in this study, with AMSTAR scores ranging from 5 to 11 (mean = 8.46, median = 9, SD = 1.56). Quantitative analysis revealed a very low degree of primary study overlap (Corrected Covered Area, CCA = 0.066), indicating that these reviews were based on largely distinct sets of primary evidence. Upon rigorous evaluation, the study by Kaiser et al. was identified as providing the most robust evidence (AMSTAR score: 11/11). Their pooled results indicated no statistically significant differences between decompression alone and decompression with fusion for key clinical outcomes: ODI (MD: 0.86; 95% CI: -4.53 to 6.26), VAS for back pain (MD: -5.92; 95% CI: -11.00 to -0.84), VAS for leg pain (MD: -1.25; 95% CI: -6.71 to 4.21), and reoperation rates (OR: 1.23; 95% CI: 0.7 to 2.17). However, decompression alone was associated with significantly shorter operative time (MD: -93.97 minutes; 95% CI: -125.44 to -62.50), less intraoperative blood loss (MD: -320.55 mL; 95% CI: -389.61 to -251.49), and a reduced hospital stay (MD: -1.7 days; 95% CI: -1.75 to -1.65). CONCLUSION: This study, which examines overlapping meta-analyses comparing decompression with and without fusion for LDS, indicates that currently available evidence does not support any benefits of adding fusion to decompression in treating LDS. Nevertheless, further subgroup analysis is necessary to ascertain which LDS patients might benefit from the addition of fusion to decompression.