Preoperative and postoperative evaluation by manometric study of the anal sphincter after coloanal anastomosis for carcinoma

The purpose of the present study was to pre- and postoperatively evaluate the anal sphincter after coloanal anastomosis in 20 patients with carcinoma of the rectum at 5.5 to 8 cm from the anal verge. The 20 patients matched age and sex with the controlled subjects. Of the 20 patients, 17 with normal preoperative manometric studies when compared with control subjects underwent a coloanal anastomosis as described by Castrini, and three patients with preoperative incontinence underwent abdominoperineal resection. Manometric studies preoperatively, and postoperatively at three and 12 months, indicated a statistically significant decrease in squeezing pressure, and rectal compliance at three months that almost normalized by 12 months. The rectal compliance correlated with the number of bowel movements per day at three months (four to five per day) and at 12 months (two to three per day). The rectoanal reflex and length of pressure zone have remained unchanged. Results seem to indicate that anal continence can be preserved after coloanal anastomosis.