Variables associated with 30-day postoperative complications in lower extremity free flap reconstruction identified in the ACS-NSQIP database

Background: Lower extremity free flaps are a common way to treat both traumatic and oncologic lower extremity wounds. These patients often suffer postoperative complications. We sought to use the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database to identify variables associated with postoperative complications. Methods: Patients who had free flap procedure and a primary diagnosis code for lower extremity pathology were identified in the NSQIP database from 2006 to 2017. NSQIP includes data on preoperative, intraoperative, and postoperative variables, including information up to 30 postoperative days. Current procedural terminology (CPT) codes for free flaps and international classification of diseases (ICD) 9 and 10 codes for lower extremity pathology were used for our cohort. We examined overall and major complication rates. Major complications were defined as reoperation, readmission, organ space infection, or death. Univariate and multivariate analyses were used to identify associations with complications. Results: Four hundred and eighty-three patients underwent lower extremity free flaps. Overall complication rate was 31.6% and major complication rate was 14.9%. Prolonged operative time (OR = 2.81, CI:1.76–4.48, p <.001), preoperative steroid use (OR = 3.04, CI:1.12–8.29, p =.030), and preoperative anemia (OR = 4.10, CI:2.00–8.41, p <.001) were independently associated with any complication. Diabetes (OR = 2.56, CI:1.24–5.29, p =.011) and prolonged operative time (OR = 3.75, CI:2.17–6.47, p <.001) were independently associated with major complications. Conclusions: In lower extremity flap reconstruction, associations with overall complications include prolonged operative time, steroid use, and anemia. Associations with major complications included diabetes and prolonged operative time. These associations can be used to guide interventions on patients identified to have greater risk of complications.