The pig as an experimental model for colonic healing study of leakage and ischemia in colonic anastomosis.

Background: The object of this experimental study was to develop a model of anastomotic failure due to primary leakage and ischemia in porcine large bowel anastomosis.

Methods: End-to-end anastomosis was constructed at descending colon in 12 pigs. The pigs were randomly divided into three groups. In Group A, the anastomosis was applied with a leak of 18 mm. In Group B, in addition to primary leakage, an artificial ischemia of the proximal anastomotic bowel segment was created by ligation of supplying vessels over 5 cm. In Group C, an artificial ischemia was created in the same manner at the proximal and distal anastomotic segment and the anastomosis was applied with an intentional leakage as in Groups A and B. The animals were sacrificed immediately in case of clinical signs of anastomotic dehiscence, sepsis, peritonitis, or ileus. The animals were sacrificed on day 28. The peritoneal cavity was examined for peritonitis, anastomotic wound dehiscence, and pericolic abscess formation.

Results: Distinct fibrinous coverings and adhesions at the anastomotic area were found in all animals. In cases of primary leakage without ischemia, only one of the four animals developed abscess at anastomotic side with clinical sepsis. In cases of primary leakage with ischemia of the proximal anastomotic bowel segment, one of the four animals presented generalized peritonitis with sepsis. In Group C, there were no signs of leakage or peritonitis, although three of the four animals developed colonic ileus due to obturation of the colonic lumen by a clot of necrotic bowel wall.

Conclusion: Large anastomotic dehiscence and local ischemia of the bowel wall are not reliable factors for the development of intra-abdominal abscess, peritonitis, or sepsis in the pig model.