Anorectal manometry

During anorectal manometry, a thin, soft, flexible tube (about the width of a finger) is gently inserted into your back passage. It has tiny pressure sensors along its length that measure how strongly your sphincter muscles are squeezing — both at rest and when you actively contract them. A small balloon at the tip can be gently inflated to check how your rectum responds to the feeling of fullness, and to test a normal reflex that helps coordinate bowel control.

The whole test takes around 15 minutes. It uses no radiation and is always performed with you fully awake — because the test relies on you being able to squeeze, push, and relax to order, you need to be cooperative throughout.

The test is performed in two settings:

• In the Heidelberg rooms — as a stand-alone outpatient test. No sedation, no hospital admission, you can drive yourself there and home.
• At the hospital, just before an endoscopy (most commonly a colonoscopy or flexible sigmoidoscopy). In this case the manometry is done before the sedation is given, because you need to be awake and cooperative for it. The endoscopy then follows under sedation in the same sitting, and your recovery follows the standard endoscopy aftercare — including arranging someone to drive you home.

One of the most useful things this test can identify is pelvic floor dyssynergia (also called anismus) — a pattern where the muscles that should relax during a bowel motion are instead tightening. Because it often responds well to pelvic floor physiotherapy, identifying it explicitly often changes the entire management plan. See also the Pelvic Floor Dysfunction condition page.

• You have faecal incontinence (difficulty controlling your bowels) and an objective measurement of sphincter strength is needed before deciding on treatment
• You have chronic constipation or difficulty emptying your bowels fully — the test can reveal whether the muscles are working in a coordinated way
• You are being assessed before sacral neuromodulation (bowel pacemaker) or sphincter repair surgery, to create a baseline measurement
• You have an anal fistula and a fistulotomy is being planned — the test checks how much sphincter muscle can safely be cut without affecting continence
• Pelvic floor dyssynergia is suspected — see the overview above for why this matters
• You have had rectal or anal surgery and need a check of how things are functioning afterwards

• No sedation, no anaesthetic, no needles — just a short and generally comfortable test
• Gives objective, precise measurements rather than estimates, which helps match the right treatment to your specific problem
• Can detect anismus (also called pelvic floor dyssynergia) — a pattern where the pelvic floor muscles push in the wrong direction during a bowel motion, which often responds well to pelvic floor physiotherapy
• No radiation
• You are in and out in under an hour and can get on with your day

• You may feel some pressure or mild discomfort when the catheter is inserted or the balloon is inflated — most people find it manageable, similar to the sensation of needing to open your bowels
• There is a very small chance of minor irritation to the lining of the back passage, but this is rare and settles on its own
• There are no anaesthetic risks and no operative risks
• The results need to be interpreted alongside your symptoms and other tests — the numbers alone do not tell the whole story, which is why specialist review matters

If your test is booked in the rooms (stand-alone outpatient test):

• No special preparation needed — just try to empty your bowels naturally before you come in, as you normally would
• Eat and drink normally, and take your regular medications as usual
• No fasting required
• You can drive yourself there and drive home straight after

If your test is booked at the hospital before an endoscopy:

• Follow the preparation instructions for the underlying endoscopy — see the Colonoscopy or Flexible Sigmoidoscopy page for the relevant bowel prep and fasting
• There are no extra steps for the manometry itself
• You will need a responsible adult to drive you home, as you will be sedated for the endoscopy that follows

• You will lie on your left side on the examination couch — this is the most comfortable position
• Mr Nguyen gently inserts the small catheter into your back passage, and interprets the readings as the test runs
• You will be asked to squeeze, push, and relax at different moments while the machine records the pressure readings
• The small balloon is inflated a little at a time — you will be asked to say when you first feel something and when it feels like you need to go
• The manometry itself takes about 15 minutes. If it is being done before an endoscopy, the sedation is given immediately afterwards and the endoscopy follows in the same sitting.

• If the manometry was a stand-alone test, there is no recovery time — you can leave and get on with your day immediately
• If it was done before an endoscopy, your recovery follows the standard endoscopy aftercare — a short rest in recovery, no driving for the rest of the day, and the usual sedation precautions
• A small number of people notice very mild discomfort for an hour or two afterwards, but this is uncommon and passes on its own
• Your results will be reviewed and discussed with you at your next appointment, alongside what they mean for treatment

Questions or concerns after your test: Please call our rooms on (03) 9816 3951 and leave a message — this will be sent directly as a text to Mr Nguyen. Alternatively, you may text the office mobile on 0499 090 126. We aim to respond promptly during business hours.

Emergencies: For any life-threatening emergency, call 000 immediately or go to your nearest emergency department. Do not wait for a call back from our rooms. For the Austin Hospital Emergency Department: (03) 9496 5000.