Same-day spine surgery at an ambulatory surgical center versus hospital outpatient department: a propensity-matched analysis of complications and patient-reported outcomes using the Michigan Spine Surgery Improvement Collaborative Registry.

OBJECTIVE: Although many authors have shown the safety of outpatient spine surgery, few have compared same-day spine surgery in the ambulatory surgical center (ASC) versus the hospital outpatient department (HOPD). The purpose of this study was to compare the safety of anterior cervical arthrodesis/arthroplasty or lumbar decompression with same-day discharge performed at the ASC versus HOPD.

METHODS: After IRB approval, a retrospective, propensity-matched, comparative cohort analysis of a statewide, prospective, multicenter, spine-specific database (Michigan Spine Surgery Improvement Collaborative [MSSIC]) was undertaken. Patients who underwent lumbar decompression or anterior cervical arthrodesis/arthroplasty (1 or 2 levels) with same-day discharge from January 1, 2021, to June 30, 2023, were reviewed. The HOPD/ASC matched cohorts were created at a ratio of 4:1 based on BMI, American Society of Anesthesiologists physical status class (ASA), and operative levels. The primary outcome variables investigated included any complication, return to operating room (OR) within 90 days, and emergency department (ED) visit or readmission within 30 and 90 days. Secondary outcome measures investigated included patient-reported outcome (PRO) measures at 90 days and 1 year and return to work at 90 days and 1 year. Differences between HOPD and ASC patients were tested using univariate comparisons for both the anterior cervical and lumbar decompression cohorts. Multivariate analysis was performed for the lumbar decompression group.

RESULTS: After matching, 3351 patients who underwent outpatient lumbar decompression (2679 HOPD and 672 ASC) and 806 patients who underwent anterior cervical arthrodesis/arthroplasty (644 HOPD and 162 ASC) were included in the analysis. In the univariate analysis for anterior cervical arthrodesis/arthroplasty, there were no differences between HOPD and ASC groups in terms of any complication, PROs at 90 days or 1 year, and return to work at 90 days and 1 year (p > 0.05). In the univariate analysis of the lumbar decompression group, there were higher rates of complications and return to the OR for the ASC group compared to the HOPD group (8% vs 5.5% [p = 0.01] and 4.9% vs 2.1% [p < 0.001], respectively), which remained in the multivariate analysis (incidence rate ratio [IRR] 1.5 [p = 0.001] and IRR 2.3 [p < 0.001], respectively). There were no differences between the groups in terms of PROs at 90 days and 1 year.

CONCLUSIONS: Although both outpatient anterior cervical surgery and lumbar decompression can be performed safely and effectively in ASC and HOPD, there is a slightly higher risk of return to the OR for patients who undergo lumbar decompression in the ASC. Given similar outcomes, future studies should focus on patient and payer cost differences between ASC and HOPD.