Do Anterior-Posterior Lumbar Fusions Provide More Short-Term Value Than Posterior-Only? An Application of the Operative Value Index.

Abstract

Introduction: Lumbar fusion is a common treatment for degenerative spine changes. Although both anterior-posterior (AP) and posterior-only approaches are used, their cost-effectiveness remains uncertain. This study aims to compare the costs and short-term "value" (outcomes per dollar spent) of AP and posterior-only lumbar fusions using time-driven activity-based costing (TDABC) and patient-reported outcomes.

Methods: A retrospective review of AP and posterior lumbar fusions from 2017 to 2022 was conducted. TDABC was used to assign intraoperative costs based on resource utilization, and the Oswestry Disability Index (ODI) was collected preoperatively and 3-months postoperatively. The Operative Value Index (OVI) was defined as the percent improvement in ODI per $1000 spent. Kruskal-Wallis analysis and multivariable regression compared costs, operative times, and OVI between AP and posterior-only lumbar fusions.

Results: Among 108 analyzed patients, 33 underwent AP fusion and 75 underwent posterior-only fusion. The average cost of AP fusion ($22,590) was significantly higher than posterior-only fusion ($10,768) (p<0.001), driven by greater supply (p<0.001) and personnel costs (p<0.001). AP procedures also had longer operative times but showed no significant difference in ODI improvement (p=0.473). Although posterior-only was associated with significantly higher OVI (p<0.05) on univariate analysis, multivariable regression revealed no significant difference in OVI between posterior-only fusions and AP fusions (p=0.098).

Conclusions: We provide a novel "value" metric that integrates granular costing methodology with prospectively collected patient-reported outcomes. Although AP fusions incur significantly greater cost than posterior-only fusions, there was no significant "value" difference between the two modalities when accounting for confounders.