IMPORTANCE: Few studies have examined the association between enhanced recovery after surgery (ERAS) compliance and postoperative outcomes within head and neck (HN) free flap reconstructive surgery. Doing so may inform future interventions to improve ERAS adoption and improve postoperative outcomes. OBJECTIVE: To assess overall compliance with ERAS guidelines and its association with postoperative outcomes among individuals undergoing HN free flap reconstructive surgery. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study included patients who underwent ERAS-guided HN major reconstructive surgery in Alberta, Canada between January 2017 and September 2021. Data analysis occurred from May 2024 until August 2024. MAIN OUTCOMES AND MEASURES: ERAS compliance was assessed for 17 ERAS care elements, and the total compliance score for each patient was a sum of the compliance for each ERAS care element. Compliance was categorized as low compliance (<
53%), moderate compliance (53%-72%), and high compliance (>
72%). Postoperative outcomes included hospital length of stay and hospital readmission and emergency department admissions within 30 days, intensive care unit readmission, complications, and severe complications. Unadjusted and adjusted models (using backward stepwise regression) assessed associations between ERAS compliance (exposure) and postoperative outcomes. RESULTS: Of 257 patients, 90 (35.0%) were female, and the mean (SD) age was 62.4 (13.3) years. Overall, 196 (76.3%) had moderate compliance, 50 (19.5%) had low ERAS compliance, and 11 (4.3%) had high compliance. Preoperative (86%) and intraoperative (73%) ERAS compliance exceeded postoperative compliance (38%). Compliance for ERAS care elements varied widely, with the highest compliance observed for preincision antibiotic prophylaxis (99.6%) and the lowest compliance observed for postoperative early mobilization (10.2%). Postoperative hospital length of stay decreased by 0.71 days (95% CI, -1.34 to -0.08), and the odds of experiencing complications decreased by 28% (odds ratio, 0.72
95% CI, 0.56-0.90) for each 1-unit increase in the total ERAS compliance score. CONCLUSIONS AND RELEVANCE: This results of this cohort study suggest that higher overall compliance with ERAS guidelines was associated with improved postoperative outcomes for individuals undergoing major HN free flap reconstructive surgery. There also appeared to be discrepancies in compliance between preoperative and postoperative phases, suggesting areas for interventions designed to improve adherence to ERAS protocols and underscoring the need for proactive compliance monitoring for optimizing patient outcomes in major HN surgery.