End to end versus end to side microvascular anastomosis for traumatic lower limb free flap reconstructions: A systematic review and meta-analysis.

Background: Free flap reconstruction of the lower extremity is technically challenging and may suffer from higher complication rates than other anatomical sites. One important vascular consideration in the reconstructive process is the microsurgical anastomotic technique, namely whether an end-to-end (ETE) or end-to side (ETS) technique is used. The ETS technique is often preferred by lower limb microsurgeons, who describe its benefits of improved distal perfusion. However, this preference remains based on individual experience or poor evidence. Methods: A systematic review of the evidence was performed, with inclusion of specifically traumatic lower limb wounds requiring free tissue transfer. Flap failure was utilised as the primary outcome, with secondary outcomes including thrombosis. Results: Six articles, with 1153 microvascular anastomoses were included. Meta-analysis results revealed no statistical significance in flap failure when comparing ETS to ETE (OR 0.72, CI 0.45-1.15). Included articles were limited by study design (case series) and therefore only provided level IV evidence. Conclusion: Although further research is required to elucidate the outcomes of both microvascular anastomotic techniques, the results of this review and the wider literature at present do not provide support for any microvascular anastomotic technique over the other.