Blood supply to anastomosis

The vascular supply to the bowel is via the mesentery. The superior mesenteric artery gives rise to the arcuate system that supplies the vasa recta of the small intestine. This configuration leaves the antimesenteric border of the bowel at the highest risk for ischemia.
If an anastomosis is constructed off to one side of the bowel, there will be a shorter distance for the blood supply to reach the mesenteric aspect of the anastomosis. However, the blood supply to the antimesenteric aspect of the anastomosis must travel a considerably longer distance over the antimesenteric border of the bowel. That puts the antimesenteric aspect of the anastomosis at a much higher risk of ischemia. For this reason, we suggest centering side-to-side and side-to-end anastomoses on the antimesenteric border of the bowel, rather than off to one side, whenever possible, to minimize ischemia.