Anterior Cervical Discectomy and Fusion for Adjacent Segment Disease: Clinical Outcomes and Cost Utility of Surgical Intervention.

Abstract

Retrospective review. Determine clinical outcomes and cost utility of anterior cervical discectomy and fusion (ACDF) for the treatment of adjacent segment disease (ASD). 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. 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. 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. 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.