Evolution of Length of Stay in Microsurgical Breast Reconstruction: A National Big Data Study of 21,777 Flap Cases from a 16-Year ACS-NSQIP Analysis

Background: Reducing postoperative length of stay (LoS) benefits both patients and hospi- tal systems. This study leverages the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to identify predictors of extended LoS following microsurgical free flap breast reconstruction. Methods: We retrospectively analyzed NSQIP data (2007–2022) to identify factors influencing LoS after free flap reconstruction, using CPT code 19364 to identify cases. Candidate predictors were chosen based on clinical relevance and entered into a Poisson regression model. A backward stepwise selection approach, guided by Akaike’s Information Criterion (AIC), was applied to derive the most parsimonious model. Incidence rate ratios (IRRs) with 95% confidence intervals (CIs) were reported. Results: A total of 21,771 free flap reconstructions were analyzed. Procedure volume increased annually between 2007 and 2022, during which mean LoS decreased by 31.25%, from 4.64 to 3.19 days. Each year was associated with a 2.6% reduction in LoS (IRR = 0.974; 95% CI: 0.972–0.976). Longer operative time increased LoS by 6.2% per hour (IRR = 1.062; 95% CI: 1.060–1.065). Dia- betes and bleeding disorders increased LoS by 5.8% and 15.1%, respectively. ASA II and III were associated with 4.4% and 8.5% longer LoS vs ASA I. Conclusions: From 2007 to 2022, LoS for free flap breast reconstruction significantly declined, reflecting advancements in surgical techniques and perioperative care. Key predictors of extended LoS included operative time, comorbidities, and ASA classification. Findings provide valuable insights for risk stratification and surgical planning.