Procedural stacking as an independent marker of thirty-day morbidity in plastic surgery: A national cohort study

BACKGROUND Combined procedures are common in plastic surgery, but risk is framed by operative time rather than by the number and burden of additional procedures. METHODS We analyzed American College of Surgeons National Surgical Quality Improvement Program plastic surgery cases from 2014 to 2023. Stacking burden was 0, 1, 2, or ≥3 additional Current Procedural Terminology-coded procedures. Multivariable logistic regression was used to evaluate 30-day wound complications, reoperation, readmission, and medical complications, adjusting for patient factors, operative time, primary-procedure work relative value units (wRVUs), and procedure family. Moreover, absolute risk differences, wRVU-weighted burden, and operative-time interaction were evaluated. RESULTS Among 286,295 cases, 160,098 (55.9%) included ≥1 additional procedure. Compared with none, ≥3 additional procedures were associated with wound complications (odds ratio 1.12, 95% confidence interval 1.07-1.18), reoperation (1.54, 1.46-1.63), readmission (1.41, 1.33-1.50), and medical complications (1.31, 1.21-1.42). Adjusted absolute increases were 0.51, 1.48, 1.01, and 0.40% points (numbers needed to harm, 195, 67, 99, and 251; ΔAUC 0.000-0.005). Weighted burden remained associated with all outcomes (odds ratios 1.04-1.09 per 10 wRVUs). Absolute increases were greatest in operations that lasted ≥240 min (wound complications 1.76, reoperation 2.54, and readmission 1.90% points). Cross-family stacking was associated with wound complications and readmission. CONCLUSIONS Procedural stacking is associated with higher 30-day morbidity independent of operative time and primary-procedure wRVUs, and it was most strongly associated for reoperation and readmission and during prolonged operations. The number and breadth of additional procedures, although they did not improve discrimination, provide preoperative information that should be weighed alongside expected duration in combined operations.