Defecation mechanisms in conscious dogs after total colectomy with ileorectal anastomosis.

To clarify defection mechanisms in those with total colectomy, we performed comparative studies of intestinal motility in two groups of straight and J-pouch ileorectal anastomosis. In the straight group, 98 percent of the interdigestive migrating contractions (IMC) reached the anastomosis and 48 percent of the defecations were affected by the contractions. In the J-pouch group, 16 percent of the contractions reached the anastomosis and only 8 percent of the defecations were related to the contractions. We conclude that transmission of IMC to the rectum is related to the frequency of defecation after total colectomy and that the disappearance of IMC in the J-pouch anastomosis reduced the frequency of defecations in those instances.