Anorectal function after low anterior resection for carcinoma.

Anorectal function was studied in 13 patients with carcinoma of the rectum 6-12 cm from the anal verge, which was treated by low anterior resection (LAR), and in 13 age- and sex-matched control subjects. Patients were studied before and 3 and 12 months after operation. Anal resting and squeeze pressures were the same in patients and control subjects and were decreased only moderately after surgery, with a slight increase in maximum squeeze pressure 12 months after operation. Three of the patients had an inverse rectoanal reflex before operation, and two had no reflex at all. After operation, only two patients showed a normal rectoanal inhibitory reflex, and none gained a normal reflex within 12 months after surgery. Rectal compliance was significantly reduced before operation, compared to control subjects, and was still significantly lower 3 months after operation. After 12 months, however, rectal compliance had returned to preoperative level in all but two patients with coloanal anastomosis, who still emptied the bowel 4-5 times daily.