Overview
A thin pressure-sensing catheter (about the diameter of a pencil) is gently inserted into the rectum. It measures resting and squeezing pressures of the anal sphincters, sensation thresholds in the rectum, and what your muscles do when you bear down. Combined with the balloon expulsion test (you try to push out a small water-filled balloon), it diagnoses pelvic floor dyssynergia.
Who needs it
Chronic constipation not responding to laxatives
Fecal incontinence
Pre-/post-surgical sphincter assessment
Suspected Hirschsprung's disease
Risks
Discomfort during catheter insertion
Mild rectal bleeding from existing hemorrhoids: rare
Vasovagal reaction: rare
Before the procedure
Empty bowel — most clinics ask you to use a small enema 1 hour before.
No special diet.
No sedation needed; no driving restriction.
When to See a Doctor
Call your doctor or go to emergency if after the procedure you have severe or worsening abdominal pain, fever, repeated vomiting, heavy bleeding, black stools or fainting.
Why it is done
To diagnose pelvic floor dyssynergia (the cause of constipation when laxatives don't work), evaluate fecal incontinence, assess anal sphincter function before or after surgery, and check for Hirschsprung's disease in young patients.
During the procedure
You lie on your side. The thin catheter is gently inserted into the rectum. The technician asks you to: squeeze, relax, bear down (push as if defecating), and tell them when you feel a balloon being inflated in the rectum (sensation testing). Then a small water-filled balloon is placed in the rectum and you sit on a commode and try to expel it. Total: 20-30 minutes. Mildly uncomfortable but not painful.
After the procedure
You can leave immediately. No restrictions on activity, eating, or driving. Mild rectal discomfort for a few hours. Results usually within 1 week.
When you get the results
Within 1 week.
Alternatives
Defecography (X-ray or MRI during defecation) provides anatomical information but is more involved and not always needed.
In Saudi Arabia
Anorectal manometry is available at several Saudi tertiary centers (KFSH, KFMC, KAMC) and a growing number of private hospitals in Riyadh and Jeddah. Reluctance to discuss bowel function delays many patients — this is a routine test for GI clinicians.
Questions to ask your doctor
• Could pelvic floor dyssynergia be the cause of my constipation?
• Will biofeedback help me?
• Is biofeedback covered by my insurance?
Source and review
This guide comes from the Saudi Gastroenterology Association (SGA) patient library, prepared by the SGA Patient Education Panel. Last reviewed: 2026-04-24. It is for education and does not replace your doctor's advice.
Frequently Asked Questions
What is Anorectal Manometry & Balloon Expulsion?
Why is Anorectal Manometry & Balloon Expulsion done?
What are the risks of Anorectal Manometry & Balloon Expulsion?
How do I prepare for Anorectal Manometry & Balloon Expulsion?
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