Anorectal manometry is a procedure that allows physician to examine and document the function of the rectum and anal sphincter, and the movement of the large intestine in order to investigate the cause of chronic constipation, abnormal bowel movement, in ability to restrain bowel movement, or difficulty having bowel movement.

     The physician begins by inserting a small flexible tube (about 0.4 cm in diameter) called manometry catheter into the rectum about 10 cm. deep. The catheter has a small balloon at the tip that is filled with air. During the exam, the physician asks the patient to squeeze and relax the anal sphincter while holding in the stool and while pushing the stool out in order to check for abnormality in the function of the rectum and the anal sphincter. The next step is to examine the nerves and reflex of the rectum by filling the balloon with varying volume of air, starting from 10 ml until 120 ml. The patient must inform the physician of any rectal sensation or feelings each time. During the exercises, the anal sphincter muscles pressure are measured and recorded.

 

     For patient who is constipated, the physician will fill the balloon with 50 ml of water and let the patient try to push the catheter out. This test will reveal the patient's ability to push stool out so the physician can assess the level of abnormality.

     Patient must stop taking medication that may have an effect on the feeling of the rectum or on the ability to relax or squeeze the anal sphincter at least 3 days prior to the exam. Therefore, you must inform your physician of all the medication you are currently taking.

The physician will assess the movement of the large intestine and the function of the rectum through a computer and summarize the result in order to plan and provide appropriate treatment for the patient.