Anal sphincter function after colectomy, mucosal proctectomy, and ileoanal anastomosis.

Anal sphincter investigations were performed in 41 patients with straight ileoanal anastomosis and in 10 controls. In 20 patients (group I) the mucosal stripping had been performed from the abdominal side, leaving 1-2 cm of distal anal mucosa. In 21 patients (group II) the anal mucosa had been stripped from the perineal side as far as the dentate line. Continence was perfect in all patients in group I and poor in 6 of 17 patients in group II, when examined 12 months after the operation. Anal canal resting pressure was normal in group I. In group II the resting pressure was significantly decreased and correlated to continence function. The maximum anal canal squeeze pressure was the same in the two groups. The slope of the regression line between pressure rise and integrated electromyography proved to be a useful criterion of the external anal sphincter function and was significantly correlated to degree of incontinence. This variable was significantly smaller in group II patients than in group I and controls. Thus, function of the anal sphincters was normal after mucosal proctectomy performed from above with preservation of a mucosal brim. Dysfunction of the internal and external anal sphincter was found after perineal mucosal dissection and was correlated to continence function.