What anorectal manometry is
Anorectal manometry is a test that measures how well the muscles and nerves in your rectum and anal sphincter are working. A thin, soft tube with pressure sensors sits in the rectum and records how those muscles squeeze, relax, and coordinate. The result is a set of pressure readings and a graph that your gastroenterologist reads to find out why your bowels are not behaving the way they should. We perform anorectal manometry here at our Fort Smith Main Clinic, 3416 Old Greenwood Rd, so it is not a test you have to travel for. It is often called a rectal motility test. "Motility" simply means movement. Your lower digestive tract depends on a series of muscles working in the right order at the right time. When that order breaks down, you can end up with constipation you cannot push through, or leakage you cannot hold back. Manometry shows which part of the system is out of step. It is a distinct test from esophageal manometry, which measures muscle function much higher up, in the swallowing tube, and is ordered for a different set of symptoms.
Why your doctor may order this test
Your doctor orders anorectal manometry when your symptoms suggest a muscle or nerve problem rather than a structural one. It is also one of the ways we sort out the conditions mistaken for hemorrhoids when bleeding or discomfort does not add up. Blood work, a colonoscopy, or imaging can rule out growths, inflammation, and blockages. None of those tests can tell you whether your pelvic floor muscles are squeezing when they should be relaxing. Manometry can, which is why the two tests are often used together rather than as substitutes for each other: a colonoscopy Fort Smith looks at the lining of the colon and rectum for disease, while manometry looks at how the muscles around the rectum function.
Constipation that has not improved
If you strain, feel like you never finish, or need to help stool along, the problem may be coordination rather than fiber. This is one of the tests we reach for when chronic constipation treatment has not responded to the usual measures. In a healthy push, the abdominal muscles tighten while the pelvic floor and anal sphincter relax. In many people with stubborn constipation, those muscles tighten instead. Manometry catches that pattern, and it responds well to retraining rather than more laxatives.
Trouble controlling bowel movements
Leakage, urgency, and accidents, what we call bowel incontinence treatment, can come from a weak sphincter, reduced rectal sensation, or nerve injury after childbirth or surgery. The test measures resting pressure, squeeze strength, and how much volume your rectum can hold before you feel the urge. Those numbers point toward the right treatment.
Before or after certain surgeries
Your surgeon may want baseline muscle readings before an operation near the rectum, or answers about why symptoms changed afterward. In children, the test also checks for a reflex missing in certain congenital conditions.
How to get ready
Preparation is usually simple, but follow the instructions our office gives you rather than a general list. Most patients are asked to clear the lower rectum with one or two enemas an hour or two before the appointment, eat normally, and take usual medicines, though your doctor may ask you to pause laxatives or anything that changes muscle tone for a day or so. Bring a list of your medications and a short history of your symptoms. You will not need a driver, since sedation is not used.
What happens during the test
The test is short and you stay awake the whole time. You lie on your left side with your knees drawn up. A nurse or technician places a thin, flexible catheter, about the width of a thermometer, into the rectum through the anal sphincter. Most people describe it as pressure or fullness rather than pain. Once the catheter is in place, you will be asked to do a few simple things while the sensors record:
- Rest quietly so the equipment can measure your baseline sphincter pressure
- Squeeze as if you are holding back a bowel movement
- Push or bear down as if you are trying to pass stool
- Cough, which tests a reflex that protects against leakage A small balloon on the end of the catheter is then inflated in stages. You tell the staff when you first feel something, when you feel the urge to go, and when it becomes uncomfortable. That tells your doctor how sensitive your rectum is. Most of the appointment takes about 30 minutes.
The balloon expulsion test
Many visits finish with a balloon expulsion test, done separately from the manometry catheter. A small water-filled balloon is placed just inside the rectum, and you sit on a commode and try to push it out in private, much as you would pass a normal stool. Most people expel it within a minute. Taking noticeably longer, or being unable to expel it at all, points toward dyssynergic constipation, the muscle-coordination problem where the pelvic floor tightens instead of relaxing when you push.
What the results can tell you
The readings sort your problem into a small number of patterns, and each pattern has a different fix. Weak squeeze pressures suggest a muscle strength problem. A pelvic floor that tightens on pushing points to dyssynergic defecation. A rectum that needs a large volume before you feel anything suggests reduced sensation, which often improves with training. Results within the expected range for your age and sex are normal and point your doctor toward looking elsewhere for an explanation; results outside that range identify which specific muscle or nerve function is not working as it should. The graph is generated at the time of the test, and your gastroenterologist typically reviews it with you that same visit rather than making you wait on a mailed report. Many of these patterns respond to pelvic floor biofeedback, a form of physical therapy that retrains the muscles using visual feedback. Others improve with changes to stool consistency, medication adjustments, or treatment of a related condition. Learn more about how we approach lower GI conditions.
Frequently asked questions
Does anorectal manometry hurt?
Most patients say it is uncomfortable but not painful. Tell the staff what you feel as you go, since your feedback is part of the test.
How long does it take?
About 30 minutes for the test itself, plus check-in time. You can drive yourself home and return to normal activity right away.
Will I be sedated?
No. Sedation would relax the very muscles the test is measuring, so you stay fully awake. That also means no fasting, no driver, and no recovery period.
What is a balloon expulsion test?
It is a short add-on where you try to push out a small water-filled balloon while sitting on a commode, in private. It shows how well you coordinate the actual pushing motion, which the pressure catheter alone does not fully capture.
Are there risks or side effects to anorectal manometry?
Risks are minimal: some patients notice brief soreness or light spotting afterward. Tell staff in advance if you have a latex allergy, since some equipment contains latex components.
Is anorectal manometry the same as anal sphincter myography?
No. Anorectal manometry measures pressure and coordination using a catheter. Anal sphincter electromyography measures the electrical activity of the muscle itself, usually with a needle or surface electrode, and is ordered less often, typically when a nerve injury is suspected specifically. Your doctor will tell you which one fits your situation, and the two are sometimes done together.
Anorectal manometry vs. colonoscopy: what is the difference?
A colonoscopy uses a camera to examine the lining of the colon and rectum for polyps, inflammation, and other structural disease. Anorectal manometry does not look at the lining at all; it measures how the muscles and nerves around the rectum function. The two answer different questions, and many patients with constipation or incontinence eventually have both.
What if the test finds a problem?
That is the point of doing it. A clear diagnosis usually means a more targeted treatment, and many muscle and coordination problems improve without surgery. Your doctor will build a plan around what the readings show.
Talk with us about your symptoms
Ongoing constipation, leakage, or a change in bowel control deserves a real answer instead of another guess. Dr. Ihab Herraka and the team at the Digestive & Liver Center of Arkansas evaluate these symptoms every week, perform anorectal manometry here in Fort Smith, and will help you decide which testing makes sense for you. Call our Fort Smith main clinic at (479) 242-2888 or request an appointment at 3416 Old Greenwood Rd. More on testing and preparation in our procedures & screening articles.