Comparison of Complication Risks Following Lower Extremity Free Flap Reconstruction Based on Seven Pre-Operative Indications: Analysis of the ACS-NSQIP Database.

Background: Free tissue transfer is a valuable surgical option for the reconstruction of a myriad of complex lower extremity defects. Currently, there is a paucity of data that examines the risks of complications for each of these unique indications. Methods: Patients undergoing lower extremity free flap reconstruction from the ACS-NSQIP 2011-2019 database were stratified into groups based on the etiology and indication for reconstruction. Rates of major, surgical wound, and medical complications were compared over the first post-operative month. Multivariable logistic regression was used to identify complication predictors. Results: 425 lower extremity free flaps were analyzed. The most common indications for lower extremity free flap reconstruction were wound-related (29%), malignancy (21%), and trauma (17%). Seventeen percent of free flaps had a major post-operative complication, 9% had a surgical wound complication, and 16% had a medical complication. There were no significant differences in major complications between the indications. However, the independent risk factors for major complications varied widely. Those with an indication of malignancy and those who received a musculocutaneous free flap were significantly more likely to have a surgical wound complication compared to the remaining cohort (p < 0.05). Those requiring free flap reconstruction for orthopedic hardware related concerns as well as those with wound related indications were significantly more likely to have a post-operative medical complication (p < 0.05). Conclusion: Understanding the unique risk profiles between the various indications and populations of patients undergoing lower extremity free flap reconstruction is critical for providing accurate risk estimations and optimizing post-operative outcomes and monitoring. Keywords microsurgery, lower extremity free flap, free flap reconstruction.