Physiologic status of the anorectum following sphincter-saving resection for carcinoma of the rectum.

The physiologic status of the anorectum after low anterior resections or pull-through operations of the rectum was evaluated clinically and by manometric studies. It was demonstrated that the presence of a normal anal resting pressure and an anorectal reflex were important to achieve postoperative continence after sphincter-saving operations. In patients with anastomotic leaks and poor function, a marked high-pressure zone in the anal canal and an anorectal reflex were not found, but as local inflammation resulting from the anastomotic leak disappeared, these parameters returned to normal. A normal anorectal reflex was found in one of three patients after Bacon-type pull-through operations, but the remaining two showed an increase of anal canal pressure during colonic distention. These results indicate that an elevation of anal-canal pressure in response to colonic distention plays a significant role in fecal continence at the time of "a sense of urgency" if internal sphincter function is impaired.