Anterior Cervical Discectomy and Fusion for Adjacent Segment Disease

Study Design: Retrospective review. Objective: Determine clinical outcomes and cost utility of anterior cervical discectomy and fusion (ACDF) for the treatment of adjacent segment disease (ASD). Summary of Background Data: The incidence of symptomatic ASD after ACDF has been estimated to occur in up to 26% of patients. Commonly, these patients will undergo an additional ACDF procedure. However, there are currently no studies available that adequately describe the clinical outcomes or cost utility of performing ACDF for ASD. Methods: A retrospective review of 40 patients undergoing ACDF for ASD was performed. Baseline and 2-year neck and arm pain (NRS-NP, NRS-AP), neck disability index (NDI), physical and mental quality of life (SF-12 PCS & MCS), and Zung depression score (ZDS) were assessed. Two-year total neck-related medical resource utilization, amount of missed work, and health-state values were determined. Quality-adjusted life years (QALYs) were calculated from EQ-5D assessments with US valuation. Comprehensive costs (indirect, direct, and total cost) and the value (cost-per-QALY gained) of performing ACDF for ASD were assessed. Results: Performing ACDF to treat ASD resulted in significant improvements (P<0.05) in NRS-NP, NRS-AP, NDI, SF-12 PCS, and ZDS outcome measures. Patient-reported health states also significantly improved, with a mean cumulative 2-year gain of 0.54 QALYs. The mean 2-year cost of surgery was $32,616 (direct cost: $25,391; indirect cost: $7225). ACDF for the treatment of ASD was associated with a mean 2-year cost per QALY gained of $60,526. Conclusions: Performing ACDF for ASD resulted in significant improvements in patient pain, disability, and quality of life. Further, the mean 2-year cost-per-QALY was determined to be $60,526, which suggests surgical intervention to be cost effective. This study is the first to provide evidence that performing an ACDF for ASD is both clinically and cost effective.