Comparing Outcomes of Single Versus Double Venous Anastomosis in Free Flap Operation for Lower Extremity Defect Reconstruction: A Meta-Analysis

Background: Free flap operation is a common procedure for reconstructing defects of the lower extremity. However, venous congestion often results in flap failure in lower extremity reconstruction. Dual-vein anastomosis, one proposed solution to overcome this problem, has been controversial in terms of its efficacy. The objective of this study was to perform a systematic review and meta-analysis to assess the ef-fectiveness of dual venous anastomosis on venous congestion and flap failure of the lower extremities. Methods: PubMed/MEDLINE, Google Scholar base, and Embase were searched to identify relevant studies presenting complication rates for groups of patients who had undergone single venous or dual venous anastomosis in lower extremity reconstructions. The relative risks of the following complications between these two groups (single venous and dual venous anastomosis) were calculated: flap failure, flap necrosis, flap congestion, and take-back to operating room. Results: A total of eight articles and 1,434 flaps were included. Double venous anastomosis was performed for 607 flaps, and single anas-tomosis for 827 flaps. Etiologies of defects and types of flaps were diverse. There was no significant difference in venous congestion, flap necrosis, or flap failure between the groups with one versus two vein anastomoses. However, the dual venous anastomosis group displayed a trend toward decreasing flap-related complications. Conclusion: Although there was a trend toward decreasing flap-related complications in the double venous anastomosis group, dual venous anastomosis had no statistically significant protective effects in decreasing free flap failure in the leg.