Prospective randomized controlled study of clinical function and anorectal physiology after low anterior resection: comparison of straight and colonic J pouch anastomoses

Clinical function and anorectal physiology were studied prospectively in patients with rectal cancer after low anterior resection, randomized to either a straight anastomosis or an 8-cm colonic J pouch anastomosis. Sixteen patients (mean(s.e.m.) age 61.2(3.2) years; ten men, six women) had a straight anastomosis and 17 (mean(s.e.m.) age 61.2(3.8) years; six men, 11 women) a colonic pouch anastomosis. At 1 year after low anterior resection, a bowel function questionnaire was administered and anorectal physiology tests were performed. Patients with a straight anastomosis had significantly more frequent stools (median 6 (range 3-7) daily) compared with those who had a pouch (median 3 (range 2-7) daily; P = 0.02). A frequent sensation of incomplete defaecation was found in three patients with a straight anastomosis compared with ten who had a pouch anastomosis (P = 0.02). The mean resting anal pressures were lower after colonic pouch anastomosis (P = 0.049) but there were no differences in anal squeeze pressure, rectal sensation, volume of first sensation and compliance between the two groups. The decreased stool frequency with an 8-cm colonic pouch was not associated with measured improvements in rectal reservoir function. It is possible that reversed propulsive activity may be important in smaller colonic J pouches.