Evaluation of the cicatrization of left colon anastomoses in the presence of peritonitis: an experimental study on rats

To monitor the evolution of anastomoses performed on the distal colon in a situation of experimental peritonitis, 37 Wistar-Tecpar male rats aged 114 to 130 days and weighing on avarage 298 g were divided into two lots: group S (control, N = 18) and group P (experimental, N = 19). P rats were submitted to laparotomy and peritonitis was induced by perforating the cecum with a needle, and S rats were only submitted to manipulation of the cecum. Twenty-four hours later animals were resubmitted to laparotomy and distal colectomy was performed 1.5 cm to the peritoneal reflection. End-to-end anastomosis was performed on a single extramucosal plane using 8 separate stitches with 5-0 polypropylene sutures. The anastomoses were checked on the 3rd and 7th postoperative day. Upon opening the peritoneal cavity, the presence of alterations such as peritonitis or abscesses, adhesions, organs involved, fistulas or dehiscences was reorded. A 4.0 cm segment of the colon containing the anastomosis was resected and rupture pressure was measured. Epithelialization of the mucosal wound was evaluted and the material was studied histopathologically for inflammatory reaction and scar condition. Upon relaparotomy, peritonitis was detected in all P animals and fibrin was observed in the cavity of all animals. Adhesions were present in 2 groups, without significant differences between them. Mean rupture pressure was 108.7 mm Hg in group S and 112.0 mm Hg in group P on the 3rd day and 205.0 mm Hg in group S and 206.6 mm Hg in group P on the 7th day, with no significant difference between groups. Microscopic evolution was similar in the two groups. These results permit us to conclude that peritonitis induced by this method does not modify the healing process of distal colon anastomoses in rats