Anorectal Manometry is the measurement of pressures generated in the anorectum and its response to stimulus, namely to rectal distention. This is one of the most frequent procedures preformed in a pediatric gastrointestinal motility practice. A motility catheter with a balloon attached to its distal end is inserted in the rectum. Baseline pressures are measured, the balloon is then inflated in a serial manner. This is to illicit the recto-anal inhibitory reflex (RAIR). Absence of the RAIR is pathologic and results in the intractable constipation that is seen in Hirshsprung’s disease and anal achalasia. In older children, a number of other tests of anorectal function are also preformed including measurement of sensation, squeeze, and push. In adolescents a balloon expulsion test is often preformed concurrently.
Why is anorectal manometry done?
It is one of the tests that is done to try understand why a child has problems with constipation or fecal soiling. During the procedure we learn if the nerves of the anal canal are working properly. We also determine if the child has the strength needed to hold in stool properly.
How is the procedure done?
The test is conducted at Al Jalila Children’s. You will check in at the day surgery unit on the second floor. After registration, you and your child will be brought to the procedure room. You will be with your child during the entire test. Your child will be asked to lay on the bed on their left side. You can either lay with him or her, or sit on a chair next to the bed. A catheter about half a centimeter wide (about the size of a drinking
straw) will be placed in your child’s anus. We will measure the pressures of the anal canal and occasionally “blow up” a small balloon in the rectum to check the reflexes. At the end of the procedure your child may be asked to squeeze his or her anus or bear down as if passing stool. The procedure generally takes between fifteen to twenty minutes.
Does anorectal manometry hurt?
No, the procedure is generally painless. Children sometimes have anxiety about anal manipulation. We make an effort to help children feel as comfortable as possible during the procedure. We have child life specialists on staff to explain anorectal manometry to children and decrease anxiety during the test. You can help your child by talking to him or her about anorectal manometry before coming to the hospital, and by bringing a movie or activity for your child to do during the test. In rare cases, medicine may be given for anxiety, but it changes the pressures of the anal canal and keeps us from getting as much information as possible.