RELATIONSHIP OF SMALL-BOWEL MOTILITY TO ILEONAL RESERVOIR FUNCTION

Some patients with an ileoanal reservoir have a high defecation freque ncy, despite a good anatomical result and the absence of pouchitis. Th is study aimed to determine whether variation in function is related t o a difference in small bowel motility proximal to the reservoir and i f small bowel motility is propagated into the reservoir. Ambulatory sm all bowel and reservoir motility was studied for 24 hours in five pati ents with good function (median bowel frequency 4 per day, range 3-6) and seven subjects with poor function (median bowel frequency 12 per d ay, range 10-20). Five solid state pressure sensors were positioned in the small bowel and one in the reservoir. During the fasting nocturna l period (2300-0800 h), patients with poor function had a median of 10 (range 5-13) migrating motor complexes (MMC), significantly greater ( p=0.03) than the corresponding median number of 3 (range 2-7) in patie nts with good function. A total of 120 MMCs were observed in the whole series of 12 patients. Of these only two were propagated from the sma ll bowel into the reservoir. Discrete clustered contractions were not propagated into the reservoir, although prolonged propagated contracti ons did pass into the reservoir in one patient. Patients with poor fun ction had similar 24 hour stool output and radiological reservoir size to those with good function, but the median maximum tolerated volume on reservoir distension was 290 ml (range 160-450) for patients with p oor function compared with 475 ml (range 460-550) for patients with go od function (p=0.005). Small bowel motility proximal to the reservoir bears an important relationship to pouch function and defecation frequ ency. Propagation of coordinated proximal small intestinal motility in to the reservoir is rare.