New blood vessels develop as a gastrointestinal anastomosis heals. The
morphologic aspects of this neovascularization were studied in 22 dog
s, each of which underwent one sutured and one stapled small bowel ana
stomosis. At intervals ranging from three to 24 days after surgery, th
e dogs were killed, and the bowel was injected with Batson's compound
or india ink. The pattern of vascular growth across the anastomotic si
te was studied. Both stapled and sutured anastomoses caused an increas
e in submucosal capillary density at day three compared with control s
pecimens taken from bowel remote from the anastomotic site. This incre
ase was maintained consistently through day 24 in sutured anastomoses
but had decreased by day five in stapled anastomoses. Growth of submuc
osal vessel across the anastomotic site could be demonstrated by day t
hree in sutured and day four in stapled anastomoses. The more vigorous
inflammatory response associated with sutured anastomoses may be resp
onsible for more rapid and prominent neovascularization.