Neovascularization of canine sutured and stapled small intestinal anastomoses.

New blood vessels develop as a gastrointestinal anastomosis heals. The morphologic aspects of this neovascularization were studied in 22 dogs, each of which underwent one sutured and one stapled small bowel anastomosis. At intervals ranging from three to 24 days after surgery, the dogs were killed, and the bowel was injected with Batson's compound or india ink. The pattern of vascular growth across the anastomotic site was studied. Both stapled and sutured anastomoses caused an increase in submucosal capillary density at day three compared with control specimens taken from bowel remote from the anastomotic site. This increase was maintained consistently through day 24 in sutured anastomoses but had decreased by day five in stapled anastomoses. Growth of submucosal vessel across the anastomotic site could be demonstrated by day three in sutured and day four in stapled anastomoses. The more vigorous inflammatory response associated with sutured anastomoses may be responsible for more rapid and prominent neovascularization.