(AS1) Microscopic Lumbar Discectomy in Ambulatory Surgery Center versus Inpatient Setting: A One-year Cost Utility and Cost Benefit Analysis

Introduction: Microscopic Lumbar Discectomy (MLD) was the first spine surgery to transition to ambulatory surgery centers (ASC). However, its cost-effectiveness remains contentious, owing to the paucity of cost-utility analyses performed for ambulatory MLDs. Herein, we performed the first high-quality cost-utility analysis of patients undergoing single-level MLD in the ASC versus the inpatient setting.

Methods: 3,169 consecutive, ASA I-III patients (2,957 inpatients prospectively enrolled in the National Quality Outcomes Database (QOD), 572 from our single ASC database) undergoing single-level MLD were retrospectively reviewed, and propensity-matched to yield 400 pairs. Healthcare utilization, lost wages, and EQ5D quality of life (QOL) were evaluated over a one-year period. Direct cost (one-year unit costs based on Medicare national allowable payment amounts) and indirect cost (missed workdays x average US daily wage) were assessed and incremental cost-effectiveness ratio (ICER) was calculated.

Results: Estimated blood loss, length of surgery, and hospitalization were less for ASC vs. inpatient MLD (p < 0.001). Perioperative safety and patient-reported outcomes were similar between both cohorts. ASC vs. inpatient MLD demonstrated an accelerated return to work (p=0.004), a reduction of $8,536 (Medicare) and $13,886 (private payers) (p < 0.001), in total one-year costs and similar gain in QALYs. The inpatient setting vs ASC had a highly cost-ineffective ICER of $1,032,195/QALY-gained and $1,679,105/QALY for Medicare and commercially-insured patients, respectively.

Conclusion : Inpatient vs. ambulatory MLD is associated with increased healthcare costs without a safety, outcome, or QALY benefit. Hence, ASCs are health-economically dominant to the inpatient setting for MLD.