Dual venous outflow improves lower extremity trauma free flap reconstructions.

BACKGROUND: Venous outflow problems are the most common reasons for perioperative flap complications. The benefit of a second venous anastomosis, however, remains unclear in lower extremity trauma free flap reconstruction and warrants further investigation. MATERIALS AND METHODS: Retrospective review of our institutional flap registry from 1979 to 2014 identified 464 free flaps performed for lower leg trauma reconstruction. Patient demographics, flap characteristics, and outcomes were examined. RESULTS: A total of 219 flaps were randomly selected for preliminary analysis. Single-vein outflow was more common (72.6%) than dual-vein (27.4%); most of the recipients were in deep venous system (83.6%) versus superficial (11.9%) or both (4.6%). Two-vein anastomoses were more likely in fasciocutaneous flaps than muscle flaps (P = 0.001) and in smaller (<300 cm(2)) flaps (P = 0.002). Complications occurred in 98 flaps (44.7%); with 54 partial flap losses (24.7%), and 11 complete flap losses (5.0%). Multivariable regression analysis controlling for age, sex, flap type, presence of bone gap, flap size, vein size mismatch, and time since injury demonstrated dual-vein outflow to be protective against complications (relative risk [RR] = 0.269, P = 0.001), partial flap failure (RR = 0.351, P = 0.031), and any flap failure (RR = 0.31, P = 0.010). No significant difference in operative time was found (P = 0.664). CONCLUSIONS: Dual-vein outflow demonstrated 73% reduction in overall complications and 69% reduction in flap failure rate compared to single-vein flaps. These results suggest a protective effect of a dual-vein outflow system, and when considered together with our findings of unchanged operative time, provide evidence for preferential use of two venous anastomoses when possible for free flap reconstruction of lower extremity trauma.