Anal sphincter function after intersphincteric resection and stapled ileal pouch-anal anastomosis. This study was done to determine the effect of the direct ileal pouch-anal anastomosis upon pressure and sensory components of the anal canal and ileal pouch. These findings were related to postoperative continence. Thirty-three patients with ileal pouch-anal anastomosis (25 continent, eight with episodic minor incontinence) were studied 3 +/- 0.3 and 25 +/- 5 months after ileostomy takedown. The maximum resting pressure in the anal canal was significantly lower in patients with an imperfect result (35 +/- 5 mm Hg) than in continent patients (44 +/- 5 mm Hg) (P less than 0.05). Postoperatively the maximum squeeze anal pressure was slightly greater in continent than in incontinent patients (99 +/- 8 mm Hg vs. 87 +/- 7 mm Hg) (P greater than 0.05). The postoperative recto-(ileo-)anal inhibitory reflex was present in 27 percent. The linear correlation between strength of rectal (ileal) distension and depth resp. duration of internal sphincter relaxation as preoperatively observed disappeared postoperatively in every group of patients. Simultaneous measurements of pouch and anal pressure in patients with imperfect results revealed a reduced positive pouch anal pressure gradient compared to the continent group. This low pouch-anal pressure gradient is thought to be responsible for the increased incidence of soiling in some of our patients. 