Anorectal Manometry

Overview

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 (the recto-anal inhibitory reflex) that helps coordinate bowel control.

The whole test takes around 15 minutes and is done in the consulting rooms. There is no sedation, no hospital admission, and no radiation. You can drive yourself there and drive yourself home.

Who needs this procedure?

• You have faecal incontinence (difficulty controlling your bowels) and Mr Nguyen needs to measure exactly how strong or weak your sphincter is 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
• Hirschsprung's disease is suspected — a condition where a specific reflex in the bowel is absent from birth
• You are being assessed before sacral neuromodulation (bowel pacemaker) or sphincter repair surgery, to create a baseline measurement
• You have an anal fistula and Mr Nguyen is planning a fistulotomy — the test checks how much sphincter muscle can safely be cut without affecting continence
• You have a condition called pelvic floor dyssynergia, where the muscles that should relax during a bowel motion are instead tightening — this is treatable but first needs to be confirmed
• You have had rectal or anal surgery and need a check of how things are functioning afterwards

Benefits

• No sedation, no anaesthetic, no needles — just a short and generally comfortable test
• Gives your surgeon objective, precise measurements rather than estimates — this leads to better treatment decisions
• Helps match the right treatment to your specific problem
• Can detect anismus — a condition where the pelvic floor muscles push in the wrong direction during a bowel motion, which is very treatable with the right physiotherapy
• No radiation whatsoever
• You are in and out in under an hour and can get on with your day

Risks & considerations

• You may feel some pressure or mild discomfort when the catheter is inserted or the balloon is inflated — most people find it perfectly 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

Before the procedure

• 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
• The test happens in the consulting rooms during your appointment — there is no separate hospital visit
• You can drive yourself there and drive home straight after

On the day

• You will lie on your left side on the examination couch — this is the most comfortable position
• The nurse or technician gently inserts the small catheter into your back passage
• 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 whole test takes about 15 minutes; you can go straight back to normal activities afterwards

Recovery & aftercare

• There is no recovery time — you can leave and get on with your day immediately
• A small number of people notice very mild discomfort for an hour or two afterwards, but this is uncommon and passes on its own
• Mr Nguyen will review your results and discuss what they mean for your treatment at your next appointment

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