End to side microvascular anastomosis on rat femoral vessels using only two-throw knot interrupted sutures and a comparison of Heel first versus Classic techniques.

Abstract Background The use of a three-throw knot for anastomosis by micro-vascular neurosurgeons is the usual standard. There is an inherent belief that third throw adds an extra security to the knot. However, the third throw can make the knot heavy, unbalanced and exert undue extra pressure on the opposing walls of the small calibre intracranial vessels. The study aims to present the feasibility and efficiency of two-throw reef knot interrupted sutures for an end to side microvascular anastomosis. Methods A prospective observational study of end to side anastomosis using femoral artery to vein model was performed in 30 Sprague Dawley rats. All anastomoses were done using two-throw reef knot interrupted sutures. Ten procedures each were done by the Heel-first, Toe-first and Classic two ends techniques. Individual parameters were recorded for analysis. The delayed patency was confirmed by re-exploration after a mean duration of 19.82±8.12 days. Results The overall patency rates were 100% in the immediate and 96.43% (27/28) in the delayed period. The average clamping time, average suturing time and the average time per suture were 65.48±16.93, 40.94±11.22, and 3.18±1.10 minutes. The overall patency rates were 100% in the immediate and 96.43% (27/28) in the delayed period. Two rats died in the post-operative period. Conclusion The end to side micro-vascular anastomosis with two throw reef knots is feasible with excellent immediate and delayed patency rates.