Rectoanal inhibitory reflex following low stapled anterior resection of the rectum.

The rectoanal inhibitory reflex plays an important role in the normal mechanisms of anorectal continence. Anterior resection abolishes the reflex, but whether it recovers, particularly after inverted stapled anastomosis, is not clear. Anal manometry was performed on patients undergoing low anterior resection for carcinoma. Maximum anal resting pressure and the rectoanal inhibitory reflex were assessed preoperatively and up to two years postoperatively. The reflex was present in 43 of 46 patients (93 percent) preoperatively, in 8 of 45 patients (18 percent) on the 10th postoperative day, and in 6 of 29 patients (21 percent) between six months and one year following surgery. Twenty patients were studied more than two years postoperatively, and in 17 (85 percent) the reflex was demonstrated. In the majority of low anterior resection patients, the rectoanal inhibitory reflex is abolished by surgery, remains absent throughout the first year, and has recovered by the end of the second postoperative year. This may be important in the recovery of anorectal function in these patients.