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

BACKGROUND

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 and patient-reported outcomes.

METHODS

A retrospective review of AP and posterior lumbar fusions from 2017 to 2022 was conducted. Time-driven activity-based costing 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.