What is Anorectal Manometry (ARM)?
Anorectal Manometry (ARM) is a diagnostic test that measures the pressures generated by the anal sphincter muscles, the sensation of the rectum, and the coordination of the muscles involved in defaecation.
It uses a thin, flexible catheter with pressure sensors and a balloon at its tip, which is gently inserted into the rectum. The test provides valuable information about anorectal function that cannot be obtained from endoscopy or imaging alone, making it essential for the evaluation of functional bowel disorders.
When is ARM Recommended?
- Faecal incontinence (accidental bowel leakage)
- Severe or refractory constipation
- Obstructed defaecation syndrome (ODS)
- Pelvic floor dysfunction
- Suspected Hirschsprung’s disease
- Pre- and post-operative assessment for anorectal surgery
- Evaluation prior to biofeedback therapy
- Assessment of anal sphincter function following obstetric injury
What Happens During the Test?
Bowel Preparation
A small enema is administered 1–2 hours before the test to clear the rectum. Full bowel preparation is not required.
Catheter Insertion
You lie on your side. A thin manometry catheter is gently inserted into the rectum. Most patients find this mildly uncomfortable but well-tolerated.
Pressure Measurements
You will be asked to squeeze, relax, and push as if defaecating. Pressures are recorded throughout these manoeuvres.
Sensation Testing
The rectal balloon is inflated gradually to assess sensory thresholds and the rectoanal inhibitory reflex.
Results
Results are analysed and discussed with you at a follow-up consultation, guiding treatment planning.