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Measuring Variability and Value of Single- and Two-Level Anterior Cervical Discectomy and Fusion Using Impact Scores
Aiyush Bansal1, Kenneth T Nguyen2, Kento Yamanouchi3
1Center for Neurosciences and Spine, Virginia Mason Medical Center, Seattle, WA.
Study Design:
Retrospective single-institution cohort study.
Objective:
To characterize intraoperative supply cost variability across surgeons and procedural levels in 1- and 2-level ACDF using impact scores, and to describe within-procedure value using time-driven activity-based costing (TDABC), the Operative Value Index (OVI), and Unit Price per Outcome (UPO).
Summary Of Background Data:
Intraoperative supply costs in ACDF vary widely and are dominated by implant selection, yet absolute cost figures are institution-specific and cannot be compared across sites. Impact scores express each supply category's proportional share of total intraoperative supply cost, enabling normalized benchmarking independent of pricing.
Methods:
A retrospective review of 369 ACDF cases (Current Procedural Terminology [CPT] code 22551, 1- and 2-level) performed by five surgeons was conducted. Supply items were categorized and impact scores calculated as each category's share of total intraoperative supply cost (0 to 100 per case). Staff costs were estimated using TDABC. Neck Disability Index (NDI) and quality-adjusted life year (QALY) were collected at baseline and up to 12 months. OVI and UPO were derived from NDI and total intraoperative cost.
Results:
Demographics were similar between groups. The five highest-impact categories for 1-level ACDF were interbody (30.9%), plate (27.8%), retractor/dilator (17.4%), screw (13.8%), and drill (12.5%); for 2-level: interbody (40.9%), plate (22.1%), screw (13.8%), retractor/dilator (12.7%), and drill (9.6%). Interbody scores increased significantly with level (P<0.001). Biologic and interbody categories showed the greatest inter-surgeon variability. OVI and UPO varied more than 2.5-fold across surgeons performing the same procedure.
Conclusion:
Impact scores reveal that interbody devices dominate ACDF supply cost and grow with added levels, while biologics exhibit the greatest inter-surgeon variability. OVI and UPO provide within-procedure value benchmarks independent of institutional pricing.