1132 Are Evidence-Based Guidelines Valuable? An Application of the Operative Value Index for Lumbar Fusions

INTRODUCTION: Elective lumbar fusions have received criticism for potentially inappropriate utilization. METHODS: This study is a retrospective analysis of a prospective observational cohort of 294 patients undergoing elective lumbar fusions from March 2018 until August 2019 at a single large academic institution. All patients were preoperatively evaluated by a panel of neurosurgeons for appropriateness, as determined through guidelines from the North American Spine Society. Oswestry Disability Index (ODI) scores were collected for all patients both preoperatively and at 6-months postoperatively. Time-driven activity-based costing (TDABC) was employed to estimate both direct and indirect intraoperative costs. Individual costs were obtained by direct observation, electronic medical records, and through querying multiple departments. The OVI was defined as the percent improvement in ODI per $1,000 spent intraoperatively. Generalized linear mixed model (GLMM) regression was performed to assess whether appropriate surgeries were associated with higher OVI, when adjusting for confounders (including number of levels fused). RESULTS: Of 294 elective lumbar fusions, 92.9% (n=273) were appropriate. The average total cost of an appropriate lumbar fusion was $17,932. This cost was largely driven by the cost of supplies ($13,020) and personnel ($4,314). The average total cost of an inappropriate fusion was $20,616 (supplies: $15,467; personnel: $4,758). Average OVI was 2.27 for an appropriate fusion, compared to 0.11 for an inappropriate fusion. GLMM revealed that appropriate cases were associated with significantly higher OVI (β-coefficient 2.0, p<0.001). CONCLUSIONS: Here, we demonstrate that appropriate lumbar fusions are associated with higher value, as measured by our novel OVI metric. Specifically, appropriate fusions were associated with nearly 2% greater improvement in ODI per $1,000 spent intraoperatively. Systematic methods for increasing the appropriateness of lumbar fusions could thereby improve value at scale.