Intestinal valve formation with a simple invagination technique.

In 17 fully conditioned mongrel dogs, the small intestine approximately 50 cm proximal to the ileocecal valve was divided. Three centimeters of the proximal bowel was then inserted into the distal bowel and anastomosis was performed using interrupted 3-0 Dexon sutures in the seromuscular layer of the proximal end and through the entire thickness of the distal end. Two to four dogs were then sacrificed 2, 4, 6, 8, and 10 weeks postoperatively. Two dogs died 3 and 4 weeks postoperatively due to mechanical obstruction just proximal to the anastomosis by hair bezoar, and 15 survived without complications. Retrograde contrast radiologic examination of all segments showed no reflux. Microscopically, the serosal surface of the invaginated segment was found to be gradually covered with mucosa, and the whole segment formed a valvelike structure within 10 weeks time.