Anorectal Physiology Testing

Some patients with symptoms suggestive of pelvic floor dysfunction can benefit from undergoing anorectal physiology testing. These tests are most useful for people with either faecal incontinence/leakage or severe defecation problems or constipation. Generally we will perform these tests if the cause of a patient’s symptoms are not obvious, for information regarding treatment planning, or if we are considering a surgical intervention for a pelvic floor problem.

The specific tests performed are:

  1. 3D anal manometry – this measures the tone/strength of the anal sphincter and pelvic floor muscles, as well as the function of the muscles with certain manoevures. Problems with coordination of pelvic floor muscles and sphincter weakness/deficiency can be diagnosed with these tests.
  2. Rectoanal inhibitory reflex test – this test is simple and quick to perform. It can be a useful test to look for evidence of Hirschsprung’s disease (a rare congenital anorectal disorder).
  3. Rectal sensation testing – using a balloon, the sensitivity and compliance of the rectum can be measured. Rectal hyposensitivity can be found in patients with chronic constipation, and hypersensitivity in people with chronic pain, inflammatory bowel disease or following rectal surgery.
  4. 3D endoanal ultrasound – this test gives precise high-definition images of the anal sphincter complex. It can be particularly useful in evaluating patients for obstetric anal sphincter injury, anal fistulae, or following anal surgery.

The term ‘anorectal’ refers to the anal canal and rectum. These are the parts of your bowel just inside your bottom. The physiology tests assess the strength of your pelvis muscles, sphincter and nerves whilst the ultrasound examines the structure of the pelvic floor muscles and any damage that has occurred to them.