The Efficacy of Lumbar Hybrid Fusion for the Prevention of Adjacent Segment Disease Fact or Artifact? A Meta-analysis

Study Design: A systematic literature review and meta-analysis Objective: The aim of this study is to compare hybrid constructs with traditional fusion-only constructs for the incidence of adjacent segment degeneration (ASDeg) and clinical outcomes in patients with degenerative lumbar diseases. Summary of Background Data: Spinal fusion is a standard surgery for various pathologies of the lumbar spine, which results in changes to the biomechanics of the spine, potentially leading to ASDeg. Although ASDeg can occur slowly as a natural course, early-onset ASDeg is regarded to be related to fusion surgery. Materials and Methods: A systematic search was conducted to identify studies that match the purpose. Included studies were compared using the incidence of ASDeg, Oswestry Disability Index, Visual Analog Score, and perioperative outcomes. We calculated the Peto odds ratio and mean difference (MD) for the continuous variables, respectively. In the hybrid group, subgroup analysis was also performed among devices. Results: Among 10 papers involving 767 patients, 372 patients underwent hybrid fusion and 395 patients underwent fusion-only. ASDeg occurred in 10.2% in the hybrid and 21.5% in the fusion-only group [Peto odds ratio, 0.39; 95% confidence interval (CI), 0.23-0.64]. The MD for Visual Analog Score were 0.45 (95% CI, 0.05-0.85) between 2 groups, which was statistically significant but was too small to have clinical significance. The MD for Oswestry Disability Index was 0.93 (95% CI, -1.016 to 2.872), which was not statistically different between 2 groups. The hybrid is superior for 18 minutes (95% CI, 5.78-30.72) shorter than typical surgery. Conclusions: Hybrid lumbar surgery decreased the incidence of early-onset ASDeg for about 2 years of follow-up. Among the hybrid constructs, the interspinous devices group accomplished favorable results with a lower risk. Adjacent segment disease was not as statistically significant as ASDeg, but adjacent segment disease may show a substantial difference for >2-year follow-up.