Electric activity and motility in the side-to-side isoperistaltic ileal reservoir

Twelve dogs underwent total colectomy and ileorectal anastomosis with construction of a side-to-side isoperistaltic ileal reservoir 20 cm long. The average stool frequency was 18 per 24 hours within the first two weeks after operation, decreasing to five per 24 hours at eight weeks. Stool consistency was liquid at two weeks, becoming semisolid at eight weeks. Saline absorption from a normal segment of ileum 20 cm long was 29 mL/hr. The average saline absorption from the reservoir was 74 mL/hr at four weeks and 106 mL/hr at eight weeks. The average volume of a 20-cm segment of ileum with an intraluminal pressure of 10 cm H2O was 69 mL. The average reservoir volume with the same intraluminal pressure immediately after construction was 203 mL, increasing to 458 mL at eight weeks. Frequency of slow electric waves in the normal canine ileum was 15.71/min, which decreased to 10.21/min immediately after construction of the reservoir. By eight weeks, the slow waves increased to 13.51/min. It appears that electric activity in the muscle of the isoperistaltic lateral ileal reservoir returns to near normal eight weeks after operation. Enlargement of the reservoir in the absence of severe distention does not appear to interfere with peristaltic activity. Stool frequency is reduced simultaneously when peristaltic activity returns and the reservoir enlarges.