Are Revision Lumbar Fusions Associated with Worse Outcomes Per Dollar Spent? An Application of a Novel Operative Value Index

Introduction: To our knowledge, no study has ever assessed the cost-effectiveness of revision lumbar fusion using granular time-driven activity-based costing (TDABC). In this study, we aim to compare the true "value" (outcomes per dollar spent) of primary versus revision lumbar fusion.

Methods: This is a retrospective analysis of patients 292 patients undergoing elective lumbar fusion. A revision surgery was defined as any case of lumbar fusion after a previous lumbar spine surgery. TDABC was employed to identify intraoperative costs for all cases. Oswestry Disability Index (ODI) scores were collected both preoperatively and at 6-months postoperatively. The Operative Value Index (OVI) was defined as the percent improvement in ODI per $1,000 spent intraoperatively. Multivariable linear regression, accounting for confounders, was performed to assess whether revision surgery was significantly associated with total cost and OVI. Secondary analyses were performed to compare costs and OVI between primary fusions, revisions for prior decompression and fusion, and revisions for prior decompression alone.

Results: The average total cost of a revision fusion was $18,252 +/- $8,496, compared to $18,073 +/- $8,894 for a primary fusion. The average OVI for these groups were 1.79 and 1.65, respectively. On multivariable regression analysis, there were no significant differences in OVI (p=0.423) or total cost (p=0.841) between primary and revision cohorts.

Conclusion : Using a novel value metric, we demonstrate no significant difference between primary and revision fusions in terms of total cost and outcomes achieved per dollar spent.