Anorectal physiology after anterior resection and pull-through operation.

Sensory and motor investigations have been performed in normal subjects, in patients who had undergone low anterior resection of the rectum and in patients following Bacon-type pull-through operation. The electromechanical relationship has been clearly defined in the anal sphincter activity. The motor findings, the threshold for sensation and its quality in the patients following low anterior resection were similar to those of the controls. Following pull-through operation the anorectal inhibitory reflex is frequently replaced by a contraction of the sphincteric zone. But, sometimes, this reflex is preserved as well as a fine discriminatory sensation. These data suggest that at least some of the mechanisms of anal sphincter continence have been preserved even after complete excision of the rectum.