Objectives: This study examines the impact of a history of coronavirus disease 2019 (COVID-19) infection on patients’ outcomes after microvascular free flap surgery and to examine the recommendations on when to perform microvascular surgery after a COVID-19 infection. Methods: A retrospective chart review using the TriNetX database was completed on March 5, 2023. Two cohorts were created: (1) patients who had a positive COVID-19 diagnosis within 1 year before microvascular free flap surgery, and (2) patients with no history of COVID-19 who underwent free flap surgery. Current Procedural Terminology codes were used to identify procedures and International Classification of Diseases-10 codes were used to identify outcomes. Results: There was a total of 31,505 patients who underwent microvascular free flap surgery, 500 of whom had a diagnosis of COVID-19 within 1 year of free flap surgery and 31,005 without history of COVID-19. There was increased risk of sepsis, surgical site infection (SSI), generalized infection, gangrene, dehiscence, hematoma, seroma, intensive care unit admission, and death in patients who underwent free flap surgery within a year of COVID-19 infection. After propensity score matching, there were 498 patients in both groups. Increased risk remained for SSI and gangrene in patients with a history of COVID-19 after matching. When comparing surgical timing between 0 to 2 months after COVID-19 infection and 2 to 12 months after COVID-19 infection, there were no significant differences between groups. Conclusions: After propensity score matching, patients with a history of COVID-19 infection were at increased risk for SSI and gangrene. However, many flap surgeries cannot be delayed. This study may help counsel patients regarding the possible complications after surgery and provide a heightened awareness in the surgical team of a possible increase in infectious complications in this population. Additional studies should investigate optimal timing of free flap surgery after COVID-19 infection and ways to mitigate the risk of infectious complications.
