End-to-End versus End-to-Side Microvascular Anastomosis: A Meta-analysis of Free Flap Outcomes

Background Optimal outcomes in microsurgery have been attributed to a range of factors, with performing of end-to-end (ETE) versus end-to-side (ETS) influencing anastomotic complications and flap outcomes. Methods A systematic review of the literature and meta-analysis was undertaken to evaluate the relative risks of anastomotic complications with ETE versus ETS approaches, for arterial and venous anastomoses looking at risk ratios (RRs) for thrombosis and overall flap failure. Results RRs of thrombosis and flap failure in ETS versus ETE venous anastomosis groups were 1.30 (95% confidence interval [CI]: 0.53-3.21) and 1.50 (95% CI: 0.85-2.67), respectively. The RRs of thrombosis and flap failure in ETS versus ETE arterial anastomosis groups were 1.04 (95% CI: 0.32-3.35) and 1.04 (95% CI: 0.72-1.48), respectively. Conclusion Differences in rates of thrombosis and flap failure between ETE and ETS venous and arterial anastomoses are marginal and nonsignificant. As such, the type of anastomotic technique is best decided on a case-by-case basis, dependent on anatomical, surgical, and patient factors.