BACKGROUND: Throughout time, perineal colostomy in abdominoperineal resection, as a way to avoid abdominal colostomy, was studied. Perineal colostomy associated with a slowing down mechanism for stool transit has been studied for many years with satisfactory results. AIM: The investigation of a colic valvoplasty in dogs which have undergone an abdominoperineal resection plus perineal colostomy, and the discussion of the results achieved in clinic and histopathologic analysis are the objective of this study. MATERIAL AND METHODS: The experimental model of this research studied the colon of dogs. Sixty five animals were operated and divided in five groups: 10 animals in the pilot group, 15 animals in control group and 40 animals in 3 other groups of observation with 10, 20 and 30 days of postoperative care. The dogs underwent a rectal partial abdominoperineal resection with perineal colostomy associated to a circumferential extramucosal seromiotomy of the left colon (except in the control group). RESULTS: Through postoperative and post-mortem observation it was possible to verify solid stool before the valves showing the efficiency of the mechanism in slowing it down. The histological analysis of the valves showed connective growth with fibrosis in the whole incised serous and muscular layers, separating them. A fibrous ring diminished the colon lumen in response to the artificial valve created by the scar that appeared in the inverted suture of the serous and muscular layers. The inflammatory fibrous repair process occurred in all valves, associated to foreign body type reactions and to partial stricture of the colon lumen. CONCLUSION: The circumferential seromiotomy produces a fibrous ring that provides stool retention on the descending colon.
Colostomy; Rectum; Dogs
