Decompression alone versus interspinous/interlaminar device placement for degenerative lumbar pathologies: Systematic Review and Meta-Analysis

Introduction Interspinous (ISD) and interlaminar devices (ILD) are marketed as alternatives to conventional surgery for degenerative lumbar pathologies; comparisons to decompression-alone are limited. The present study reviews the extant literature comparing cost and effectiveness of ISDs/ILDs to decompression-alone. Methods Articles comparing decompression-alone to ISD/ILD were identified; outcomes of interest included general and disease-specific patient-reported outcomes (PROs), perioperative complications, and total treatment costs. Outcomes were analyzed at <6 weeks, 3-months, 6-months, 1-year, 2-year, and last follow-up (LFU). Analyses were performed using random effects modeling. Results 29 studies were included in the final analysis. ILD/ISD showed greater leg pain improvement at 3mo (-1.43; [-1.78, -1.07]; p<0.001), 6mo (-0.89; [-1.55, -0.24]; p=0.008), and 12mo (-0.97; [-1.25, -0.68]; p<0.001), but not 2yr (p=0.22) or LFU (p=0.09). Back pain improvement was better following ISD/ILD only at 1yr (-0.87; [-1.62, -0.13]; p=0.02). SF-36 physical component scores nor ZCQ symptom severity scores differed between groups. ZCQ physical function scores improved more following decompression-alone at 6mo (0.35; [0.07, 0.63]; p=0.01) and 12mo (0.23; [0.00, 0.46]; p=0.05). ODI and EQ-5D scores favored ILD/ISD at all time points except 6mo (p=0.07). Reoperations (OR=1.75; [1.23, 2.48]; p=0.002) and total care costs (standardized mean difference 1.19; [0.62, 1.77]; p<0.001) were higher in the ILD/ISD group; complications did not differ significantly between groups (p=0.41) Conclusion PROs are similar following decompression-alone and ILD/ISD; the observed differences do not reach accepted minimum clinically important difference thresholds. ISD/ILDs have higher associated costs and reoperation rates, suggesting current evidence does not support ILD/ISDs as a cost-effective alternative to decompression-alone.