Assisting Suspension Triangulated Continuous Suture Technique For Microvascular Anastomosis In Rat Portocaval Shunt

Portocaval shunt in rats is widely used for experimental studies of hepatic diseases, as well as for microsurgical training. Suture-based anastomosis is technically challenging due to the small diameter, thinness, and deep location of the portal and renal veins in porto-renal anastomosis for portocaval shunt. “Back wall biting” caused by blood vessel collapse is a common cause of failure in the microvascular anastomosis. Here, we report an assisting suspension triangulated continuous suture (ASTCS) technique to prevent back wall biting in end-to-end porto-renal anastomosis for portocaval shunt in rats. Briefly, the major trunk of the portal vein was isolated using an operating microscope under isoflurane anesthesia. The right renal artery was isolated and clamped. The right renal vein was ligated with 0-gauge silk suture adjacent to the infrahepatic caval vein. The right kidney was removed. The blood flow through the portal vein was blocked by ligation at both ends, and the major trunk of the portal vein was dissected. The proximal end of the portal vein was connected with the right renal artery using a stent method, and the distal end of the portal vein was anastomosed with the right renal vein in an end-to-end pattern with 10-0 nylon suture using the ASTCS technique (Fig. 1). The anastomosis was started with 3 whole-layer eversion stitches at 4, 8, and 12 o’clock positions. The suture at the 8 o’clock position was used to perform subsequent continuous eversion stitching. The guide sutures at 8 and 12 o’clock positions were pulled upward; the guide suture at the 4 o’clock position was pulled downward with the gravity of vascular clip. When stitching reached the 12 o’clock position, continuous stitching was carried out before the guide suture at the 8 o’clock position was managed with a vascular clip. Likewise, continuous stitching at the 4 o’clock position was carried out after clipping the guide suture at the 12 o’clock position. We believe that the ASTCS technique is a convenient method to prevent back wall biting in end-to-end portorenal anastomosis for portocaval shunt in rats.