Abstracts
1997 Digestive Disease Week

A novel colonic reservoir and comparison of its short term function with a straight coloanal and colonic J-pouch anastomosis in the pig.

K Z'graggen, CA Maurer, D Mettler*, C Stoupis**, S Wildi, MW Buechler. Departments of Visceral and Transplantation Surgery, Experimental Surgery* and Radiology**, Inselspital, University of Bern, Switzerland.

Early functional results after low anterior resection of the rectum and straight coloanal anastomosis (CAA) are often characterized by frequent bowel movements, urgency and varying degrees of incontinence. The formation of a colonic J-pouch (CJP) improves early function but is associated with evacuation problems in 10% of patients one year after the procedure. We evaluated the feasibility of a new colonic reservoir in pigs and compared the early functional results with those of CAA and CJP. Methods: We developed the operative technique of complete rectal resection followed by one of three reconstructive procedures, a straight CAA, a three to four cm CJP, or a novel design of a colonic reservoir (figures), in a preliminary study of six pigs. [Figure not available.]

The anastomosis to the dentate line was performed by a circular stapler (ILS-21 Ethicon). The two types of colonic reservoirs were sutured. In this study, the three reconstructive procedures were performed in equal numbers in 15 pigs weighing 18 to 25 kg. Functional results were assessed daily. The volumes of the distal colon and the reservoirs were measured radiologically on day 42 before the sacrifice of the pigs. Results: All 15 procedures were successful. The new colonic reservoir was technically simpler to prepare and required less surgical time than the CJP. One pig in each of the three groups had to be killed after 6/6/7 days because of a small bowel obstruction(CAA), a wound sepsis (CJP) and an infection unrelated to the surgical procedure (novel colonic reservoir). Of the four remaining in the CAA group, two had an increased frequency of defecation, one showed urgency and perianal dermatitis, and three had substantially reduced stool consistency or diarrhea. Of the four pigs with CJP, two had impaired pouch evacuation. All the pigs with novel colonic reservoirs defecated normally. The mean volumes of the CJP (61.3 cm³), the new colonic reservoir (43.0 cm³), and the corresponding volume in pigs with CAA (31.7cm³) differed significantly (p < 0.001). Conclusions: The novel colonic reservoir is feasible in pigs and technically simpler than the CJP. The smaller capacity of this reservoir seems sufficient for normal defecation, and the functional results were better than those with the other two approaches.