Anorectal Manometry

How does anorectal manometry work?

A manometer is a pressure transducer. It measures the pressure in your muscle contractions to determine whether they’re too strong, too weak or not triggering at the right time. A healthcare provider places the transducer inside your anus and rectum. It sends data to a machine that reads it.

The transducer is a long, flexible tube (catheter) with pressure sensors on it. On the inside end, it’s attached to a deflated balloon. When a healthcare provider inflates the balloon inside your rectum, it activates the nerves that trigger the urge to poop. This should stimulate your natural muscle reflexes.

What is the prep for an anorectal manometry?

It’s best that your anus and rectum are empty for the test. Your healthcare provider will ask you to refrain from eating before the test and to use an enema to clear out your anus and rectum at home. They’ll give you specific instructions on when and how to do this, and advice on which products to use.

What happens during the anorectal manometry procedure?

1. When you arrive for the test, you’ll undress from the waist down or change into a hospital gown. You’ll lie on a table on your side with your knees up.
2. A healthcare provider may perform a brief digital rectal exam before inserting the catheter. That means inserting a gloved finger to check for anything abnormal in your anus or rectum.
3. They’ll lubricate the end of the catheter to help it go in smoothly, then gently advance it through your anus into your rectum.
4. They’ll take pressure readings at different depths inside your rectum to establish your baseline internal pressure. Then, they’ll inflate the balloon.
5. Your healthcare provider will take pressure readings with the balloon inflated to different sizes and in different positions inside your rectum. They’ll ask if you can feel these changes or if you feel the urge to poop.
6. They’ll ask you to squeeze, relax, push and cough at different intervals. They’ll record your voluntary and involuntary muscle responses.

How long does anorectal manometry take?

It takes an average of 30 minutes. It may range from 15 to 45 minutes.

How painful is anorectal manometry?

You might find it mildly uncomfortable, particularly if you’re sore inside your rectum or anus, but it shouldn’t be painful. The catheter and the balloon only produce as much pressure as a normal poop would. If you’re anxious about it, though, you can discuss sedation with your healthcare provider.

What is a balloon expulsion test?

Your healthcare provider may combine anorectal manometry with a balloon expulsion test at the end. This is an extra step to see if you can “poop” out a filled balloon, and how long it takes you. You’ll do this part in privacy, in a sitting position. Sensors on the balloon will record the pressure and time involved.

Are there risks or side effects to anorectal manometry?

There aren’t any significant risks or side effects unless you have an allergy to the latex balloon. Your healthcare provider can provide a latex-free option if you discuss this with them in advance. If your anus or rectum was inflamed or irritated, you might feel a little sore or have mild bleeding afterward.