Anorectal Physiology and Proctogram

This test is usually undertaken to investigate abnormal defaecation (disordered defaecation), either in the form of loose stools and incontinence or in patients who have difficulty opening the bowels. It often forms part of an array of investigations which are used to assess the function of the pelvic floor and anal canal in patients experiencing such difficulties.

 

There can be a number of parts to the test depending on the equipment used in the particular facility you are attending. The test usually starts with the patient lying on their left side.  An examination of the back passage during  which the physiologist (Scientist) or specialist nurse  inserts a gloved finger into the back passage is then undertaken to ensure the rectum is empty. If it is not an enema or suppository is sometimes given to enable you to empty the bowels. A small catheter with an inflatable balloon on the tip is inserted gently into the bottom. You may be ask to contract and relax the pelvic and anal muscles. The balloon may then be gradually inflated and the pressure and volume in the balloon recorded.

 

A further probe may then be used to assess the pressures within the anal canal. This procedure may be combined with other investigations, which may be undertaken at the same or a different time. These include an endo-anal ultrasound (to examine the anal sphincters in fine detail using an ultrasound probe) and or a defecating proctogram, when contrast is inserted into the rectum and images (often in an MRI scanner) are taking as you defaecate (go for a pooh). Some units also ask the patient to have oral contrast prior to this test (a drink which helps delineate the bowel on the pictures taken). In female patients contrast may also be inserted into the vagina to make differentiation between vagina and rectum easier.