The Statistical Fragility of Lumbar Disc Arthroplasty vs Lumbar Fusion: A Systematic Review of Randomized Controlled...

Study DesignSystematic Review of Randomized Controlled Trials.ObjectivesTo assess the statistical fragility of randomized controlled trials (RCTs) comparing lumbar fusion and lumbar disc arthroplasty (LDA).MethodsFollowing PRISMA guidelines, PubMed, Embase, and Medline databases were searched for RCTs on lumbar fusion and LDA published between January 1, 2000 and August 1, 2023. Eligible studies reported dichotomous, categorical outcomes. A two-tailed Fisher's exact test was used to confirm reported P-values (α = 0.05) for each outcome.Results18 RCTs met the inclusion criteria for analysis. Across the 18 studies, 146 dichotomous outcomes were identified. The median fragility index (FI) for all outcomes was 5 (IQR: 2.0-9.0), while the median fragility quotient (FQ) was 0.022 (IQR: 0.008-0.046). Subgroup analysis revealed that adjacent segment disease outcomes had a median FI of 3 (IQR: 2.75-3) and an FQ of 0.013 (IQR: 0.013-0.014). Industry-funded studies had a significantly higher FI (6 vs 4, P = 0.036) and lower FQ (0.019 vs 0.040, P = 0.023) compared to non-industry-funded studies.ConclusionsThis systematic review demonstrates that the statistically significant findings from RCTs comparing LF to LDA are susceptible to small changes in event outcomes. Of note, industry-funded studies were found to be significantly more statistically fragile compared to non-industry-funded studies.