Optimizing venous outflow in reconstruction of Gustilo IIIB lower extremity traumas with soft tissue free flap coverage: Are two veins better than one?

Purpose The dependent nature of the lower extremity predisposes to venous congestion, especially following significant trauma. The benefit of a second venous anastomosis, however, remains unclear in lower extremity trauma free flap reconstruction. This study investigated the effect of an additional venous anastomosis on flap outcomes in lower extremity trauma reconstruction. Methods Retrospective review between 1979 and 2016 identified 361 soft tissue flaps performed for Gustilo IIIB/C coverage meeting inclusion criteria. Muscle flaps were performed in 287 cases (79.9%) and fasciocutaneous flaps in 72 cases (20.1%). Single‐vein anastomosis was performed in 76% of cases and dual‐vein anastmoses in 24% of cases. Patient demographics, flap characteristics, and outcomes were examined. Results Fasciocutaneous flaps were more likely to have two veins performed ( P  < .001). Complications occurred in 143 flaps (39.8%): 45 take‐backs (12.4%), 37 partial losses (10.3%), 31 complete losses (8.6%). Compared to single‐vein flaps, two veins reduced major complications ( P  = .005), partial flap failures ( P  = .008), and any flap failure ( P  = .018). Multivariable regression analysis demonstrated two veins to be protective against complications (RR = 2.58, P  = .009). Subset regression analysis by flap type demonstrated an even more significant reduction in complications among muscle flaps (RR = 3.92, P  = .005). Additionally, a >1 mm vein size mismatch was predictive of total flap failure (RR = 3.02, P  = .038). Conclusion Lower extremity trauma free flaps with two venous anastomoses demonstrated a fourfold reduction in complication rates compared to single‐vein flaps. Additionally, venous size mismatch >1 mm was an independent predictor of total flap failure, suggesting beneficial effects of both two‐vein outflow and matched vessel diameter.