Role of preoperative retrograde enema on inflammatory and healing parameters in colonic anastomosis: experimental study in dogs

Objective:The purpose of this experimental study was to compare the inflammatory and wound healing response of dogs submitted to colonic anastomosis with and without preoperative retrograde enema.Methods:The study included two groups of 31 female dogs (Canis familiaris). G-I (control): no preoperative bowel preparation; G-II (study): preoperative retrograde enema using a 10% glycerin solution. All the animals were submitted to laparotomy and colotomy at 20 cm from the anal verge, followed by closure with a running extramucosal single-layer suture (Prolene® 000). The animals were then anesthetized and euthanized on the 7th (n = 10) or 21st (n= 20) postoperative day (POD) to remove the anastomosed colon segment for histological and immunohistochemical analysis evaluating the parameters: anastomotic edema, vasoproliferation, abdominal adhesions, type I and III collagen, nitric oxide and myeloperoxidase. The observed differences were analyzed with the Mann–Whitney test for nonparametric data and Student's t test for unpaired samples and parametric data.Results:One animal from G-I and one from G-II died on POD 7 and POD 10 due to anastomotic complications and sepsis, respectively The groups did not differ significantly with regard to inflammatory and healing parameters, although the levels of mature collagen were significantly lower in the animals submitted to preoperative bowel preparation.Conclusion:It has been shown that both procedures are safe to be used, however, the group with bowel preparation showed a lower amount of mature collagen in the immediate postoperative period and may be constituted a preventive factor for surgical complications for this type of surgical procedure, although no evidence in this study could be determined