Are outpatient three- and four-level anterior cervical discectomies and fusion safe?

The safety of outpatient one- and two-level anterior cervical discectomy and fusion (ACDF) has been validated in a number of recent studies. However, recent advancements in anesthetic and surgical technique have rendered procedures previously only performed in an inpatient setting, such as three- and four-level ACDF, potentially amenable to outpatient management. The present study aimed to investigate the safety of outpatient three- and four-level ACDF. Retrospective cohort study The National Surgical Quality Improvement Program – a large, prospectively-collected registry – was queried to identify patients undergoing three- and four-level ACDF in an inpatient and outpatient setting. The rates of total complications, perioperative blood transfusion, and unplanned hospital readmission in three- and four-level ACDF by inpatient or outpatient surgery status. Baseline patient characteristics and 30-day outcomes were tabulated and compared by inpatient or outpatient status using bivariate analysis. A multivariate analysis was also employed to adjust for differences in baseline patient characteristics when comparing outcomes, and was also used to identify independent predictors of complications and readmissions in patients undergoing three- and four-level ACDF. In total 3,441 patients underwent three- or four-level ACDF, with 2,718 (79.0%) procedures occurring inpatient and 723 (21.0%) outpatient. Of patients undergoing outpatient ACDF, 596 patients (82.4%) underwent a three-level and 127 patients (17.6%) underwent four-level procedures. There was an increase in the utilization of outpatient procedures, increasing from 7.0% to 32.9% between 2011 and 2018. Patients undergoing outpatient surgery were younger, white, more likely to have three-level fusions (vs four-level), had a lower American Society of Anesthesiologists (ASA) classification, and were less likely to have a history of diabetes mellitus or dependent functional status. Among the inpatient and outpatient cohorts, there was no significant difference in the rates of total complications (4.49% vs 2.49%) or unplanned readmissions (4.96% vs 3.72%). Increasing age, operative duration, and ASA classification were independent predictors of complications and readmissions, however, inpatient or outpatient surgery status and number of levels fused was not. This present study represents one of the largest cohorts of patients undergoing outpatient three- and four-level ACDF. Outpatient multilevel ACDF is performed