Assessing the variation and drivers of cost in one-level lumbar and lumbosacral discectomy: a time-driven...

Optimizing the surgical episode cost of care represents a major opportunity for healthcare cost reduction. This requires determining an accurate estimate of these costs, which has historically been difficult to determine. Time-driven activity-based costing (TDABC) has emerged as a methodology for determining more accurate surgical cost drivers compared to traditional methods.

To examine cost variation and cost drivers in single-level lumbar discectomies using TDABC methodology, focusing on total hospital cost variation, differences between high- and nonhigh-cost patients and identification of main factors affecting total hospital cost.

Retrospective, multicenter, observational study conducted at an integrated healthcare system between November 2021 and December 2022.

The cohort comprised 184 patients undergoing isolated, primary single-level lumbar or lumbosacral discectomy. Revision procedures, multilevel surgeries, concurrent procedures, and cases performed by surgeons with fewer than 9 procedures were excluded.

Total hospital costs were calculated using TDABC methodology and normalized to an average of 1.00 per institutional requirements. Cost variation, cost drivers, and differences between high-cost (top decile) and nonhigh-cost patients were assessed.

TDABC methodology was utilized to calculate total costs for all procedures. Statistical analyses included descriptive statistics, bivariate comparisons between high-cost and nonhigh-cost patients, and multivariable linear regression to identify individual cost drivers.

The most expensive surgery was 3.6 times more expensive than the least expensive, with intraoperative costs comprising 79% of total expenses. A strong correlation existed between surgical time and total cost (ρ=0.78, p<.001). High-cost patients were more likely to undergo surgery at academic medical centers (89% vs 42%, p<.001), less likely to have outpatient surgery (33% vs 93%, p<.001), had a higher comorbidity burden (Elixhauser comorbidity index 3.1 vs 1.7, p=.005), and longer operative times (153 vs 59 minutes, p<.001). Multivariable analysis identified surgical time, outpatient surgery, surgery location, and individual surgeon idiosyncrasies as significant cost determinants.

Single-level lumbar discectomies demonstrate modest cost variation primarily driven by surgical time, patient complexity, and surgeon-specific factors. While efforts to reduce unwarranted cost variation without negatively impacting patient outcomes are warranted, orthopedic or neurosurgical departments and hospital systems may wish to focus their initial efforts on higher cost spine procedures with greater cost variation first before tackling single-level lumbar discectomies.