Primary Single-level Lumbar Microdisectomy/Decompression at a Free-Standing Ambulatory Surgical Center vs. a Hospital-Owned Outpatient Department – An Analysis of 90-day Outcomes and Costs

Abstract Background Context While free-standing ambulatory surgical centers (ASCs) have been extolled as lower cost settings than hospital outpatient facilities/departments (HOPDs) for performing routine elective spine surgeries, differences in 90-day costs and complications have yet to be compared between the two types of treatment facilities. Purpose We carried a comprehensive analysis to report the differences on payments to providers and facilities as a reflection of true costs to patients, employers and health plans for patients undergoing primary, single-level lumbar microdiscectomy/decompression at ASC versus HOPD. Study Design Retrospective review of Medicare Advantage and commercially insured enrollees from the Humana dataset from 2007-2017Q1. Outcome Measures To understand the differences in 90-day complications, readmissions, emergency department visits and costs for patients undergoing primary, single-level lumbar microdiscectomy/decompressions at an ASC versus HOPD. Methods The Humana 2007-2017Q1 was queried using Current Procedural Terminology codes to identify patients undergoing primary, single-level lumbar microdiscectomy/decompressions. Patients undergoing two-level surgery, open laminectomies, fusions, revision discectomies and/or deformities were excluded. Service Location codes for HOPD (Location Code 22) and free-standing ASC (Location Code 24) were used to determine surgery treatment facilities. Using propensity scoring, we matched 2 groups who had surgery performed in ASCs or HOPDs based on age, gender, race, region and Elixhauser co-morbidity index (ECI). Multivariable logistic regression analyses were performed on matched cohorts to assess for differences in 90-day outcomes between facilities, while controlling for age, gender, race, region, plan and ECI. Results A total of 1,077 and 10,475 primary single-level decompressions were performed in ASCs and HOPDs, respectively. Following a matching algorithm with propensity scoring, the two cohorts were comprised of 990 patients each. Observed differences in 90-day complication rates were not statistically or clinically significant (ASC=9.1% vs. HOPD=10.3%; p=0.362) nor were readmissions (ASC=4.5% vs. HOPD=5.3%; p=0.466). On average, performing surgery in an ASC vs. HOPD resulted in significant cost savings of over $2000/case in Medicare Advantage ($5,814 vs. $7,829) and over $3,500/case ($10,116 vs. $13,623) in commercial beneficiaries. Conclusion Performing single-level decompression surgeries in an ASC compared with HOPDs was associated with approximately $2,000-$3,500 cost-savings per case with no statistically significant impact on complication or readmission rates.