Spine Journal - 2026-07-01 - Journal Article; Multicenter Study; Observational Study
Assessing the variation and drivers of cost in one-level lumbar and lumbosacral discectomy: a time-driven activity-based costing analysis.
Hammoor BT, Bernstein DN, Enchill ZA, Tobert DG, Lightsey HM, Hershman SH, Bono CM, Fogel HA
Topics
Key Takeaway
In single-level lumbar discectomy, the most expensive case costs 3.6× the least expensive, with surgical time (ρ=0.78) and outpatient vs. inpatient setting (33% vs. 93% outpatient in high-cost patients) as the dominant cost drivers.
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Summary
This multicenter retrospective study used TDABC methodology to quantify cost variation and identify cost drivers in 184 primary single-level lumbar or lumbosacral discectomies performed November 2021–December 2022. Intraoperative costs comprised 79% of total expenses, and surgical time correlated strongly with total cost (ρ=0.78). High-cost patients (top decile) were more likely to be operated at academic centers (89% vs. 42%), had longer operative times (153 vs. 59 min), higher comorbidity burden (Elixhauser 3.1 vs. 1.7), and were less likely to have outpatient surgery (33% vs. 93%).
Key Limitation
Costs were normalized rather than reported in absolute dollars, and the 14-month single-system dataset limits generalizability to community or freestanding ambulatory surgery center environments where cost structures differ substantially.
Original Abstract
BACKGROUND CONTEXT
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.
PURPOSE
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.
STUDY DESIGN/SETTING
Retrospective, multicenter, observational study conducted at an integrated healthcare system between November 2021 and December 2022.
PATIENT SAMPLE
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.
OUTCOME MEASURES
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.
METHODS
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.
RESULTS
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.
CONCLUSIONS
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.