Patency of Different Arterial and Venous Endto-Side Microanastomosis Techniques in a Rat Model

Abstract

Microvascular anastomotic patency is the most important factor in determining a successful outcome in free-flap transfers. End-to-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 used extensively in microsurgical reconstruction. Nevertheless, the effect of venotomy shape on the patency of venous end-to-side anastomoses has not been previously reported. The purpose of this study was to compare the patency rates of end-to-side anastomoses using different techniques in both arteries and veins. In total, 104 Sprague-Dawley rats were subdivided into four groups. The rats were anesthetized, and anastomosis was performed on either the femoral artery or vein on the right with the left used as control. Vesselotomy was varied between an end-to-side hole and an end-to-side slit with patency measured immediately following surgery and at 2 weeks. No significant difference in patency or histology between these techniques was demonstrated in any group. We conclude there is no difference in patency rate between the two techniques in arterial or venous vesselotomies; however, in small vessels < 1.5 mm, the slit technique is technically easier, and clinical recommendations are given.

Thrombotic Effect of Purposeful Back-Wall Stitch for End-to-Side Microarterial Anastomosis in Rats

“…The arteriotomy shape is closely related to the back-wall stitch risk. In slit arteriotomy, the back-wall stitch risk is high compared with hole arteriotomy due to the collapse of arteriotomy walls, 3,4 as we have also observed in our clinical practice. The hole arteriotomy involving an elliptical excision of the side wall provides improved visualization and therefore a lower tendency of back-wall interference.…”

“…The hole arteriotomy involving an elliptical excision of the side wall provides improved visualization and therefore a lower tendency of back-wall interference. 4,5 However, in the ETS model, proper suture placement is more difficult because recipient and donor arteries lie in different axes, restricting visualization of the back wall. In a previous study of the effects of a purposeful back-wall stitch model (PBWS) in the ETE anastomosis, we found that a PBWS may not cause thrombosis at 1 hour and that patent anastomoses could be observed even at the end of 24 hours.…”

Anticoagulation Therapy in Microsurgery: A Review

“…4 Despite the variety of reconstructive techniques and anticoagulation protocols used by microsurgeons, the reported failure rate among free flaps ranges from 4% to 10% and the reported failure rate among replants ranges from 15% to 30%. 4,5,[13][14][15] Many flaps are salvaged successfully with thrombolytic treatment, indicating that the true rate of vascular thrombosis in microsurgery is higher. 16 Optimal prophylactic anticoagulation therapy promises significant reductions in morbidity.…”

Is the Use of Intraoperative Heparin Safe?

“…The single most important determinant of success is believed to be surgical technique. [5][6][7] Despite the current reliability of microvascular free tissue transfer, total flap loss remains a significant concern. Failures are nearly always the result of microvascular thrombosis.…”