Outpatient Anterior Cervical Discectomy and Fusion is Associated With Fewer Short-term Complications in One- and Two-level Cases A Propensity-adjusted Analysis

Study Design. Retrospective cohort study of prospectively collected data from the National Surgical Quality Improvement Program (NSQIP) database. Summary of Background Data. ACDF is increasingly performed as an outpatient procedure, with evidence demonstrating outpatient one-level ACDF to be associated with fewer postoperative complications than inpatients. The postoperative morbidity and safety of outpatient two-level ACDF as a separate cohort is not well understood. Methods. ACDF cases from NSQIP 2011 to 2014 were identified. Differences in baseline characteristics between inpatient and outpatient cases were determined, and propensity score adjustment was used to account for selection bias. Oneand two-level ACDF cohorts were analyzed separately. Unadjusted and propensity-adjusted multivariable logistic regressions were performed to determine the risk of postoperative complications in outpatient cases relative to inpatient cases, and predictors of postdischarge complications. Results. A total of 22,006 ACDF cases were included, of which 4759 were outpatient procedures. Propensity-adjusted differences in preoperative characteristics were all P > 0.5, indicating successful adjustment of selection bias. Among 6890 two-level cases, of which 1429 (20.7%) were outpatient, the overall unadjusted rate of complications was 1.47% for outpatients and 3.94% for inpatients, P< 0.001. Propensity-adjusted multivariable regression showed a lower rate of postoperative complications in the outpatient cohort (odds ratio 0.48, 95% confidence interval 0.30-0.75). Greater comorbidity burden as measured by Charlson Comorbidity Index, higher American Society of Anesthesiologists class, chronic steroid use, hypertension, and male sex were independent risk factors for postdischarge complications. Conclusion. After adjusting for selection bias and patient risk factors, outpatient two-level ACDF was not associated with increased postoperative morbidity relative to inpatients, and may be considered in appropriately indicated patients.