Patency of different arterial and venous end-to-side microanastomosis techniques in a rat model

Microvascular anastomotic patency is the most important factor in determini ng a successful outcome in free-flap transfers. End-re-end and end-to-side techniques have been shown to provide equivalent arterial patency rates in clinical and basic science studies, and end-to-side anastomoses have been u sed extensively in microsurgical reconstruction. Nevertheless, the affect o f venotomy shape on the patency of venous end-to-side anastomoses has not b een previously reported. The purpose of this study was to compare the paten cy rates of end-to-side anastomoses using different techniques in both arte ries and veins. In total, 104 Sprague-Dawley rats were subdivided into four groups. The rats were anesthetized, and anastomosis was performed on eithe r the femoral artery or vein on the right with the left used as control. Ve sselotomy was varied between an end-to-side hole and an end-to-side slit wi th patency measured immediately following surgery and at 2 weeks. No signif icant difference in patency or histology between these techniques was demon strated in any group. We conclude there is no difference in patency rate be tween the two techniques in arterial or venous vesselotomies; however, in s mall vessels <1.5 mm, the slit technique is technically easier, and clinica l recommendations are given.