Anorectal Physiology

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What is anorectal physiology?

Anorectal Physiology is a test of the anal canal muscle strength and is used to investigate symptoms of faecal incontinence or constipation. It checks the strength of the muscles at rest and during squeezing and also tests the sensitivity of the rectum to distension. In some cases it is also necessary to proceed to testing the nerve supply of the anal canal muscles. This is caused anorectal neurophysiology and involves stimulating the muscles of the anal canal and assessing the muscles response.

What is involved in anorectal physiology?

During the test you will need to remove your undergarments and lie on your left side under a sheet. A gentle rectal examination will be carried out and sometimes an enema is required to empty the rectum.
Following this a small catheter (tube) is placed in the rectum and this catheter is withdrawn at a steady rate, measuring the pressure in the anal canal as it is withdrawn. This is then repeated with the anal muscles relaxed and with the muscles squeezing the anus closed as tightly as you can.
Following this a small balloon is placed in the rectum and air inflated into the balloon. As the balloon fills you will be asked to record the sensations you feel as the balloon fills.
After this it may be nesecary to underatke anorectal neurophysiology as mentioned above.

Do I need to have any special preparation prior to the test?

No special preparation is usually necessary. It is preferable if you can refrain from eating or drinking for 2 hours prior to the test and to have opened your bowels on the day of the test. If you have not been able to open your bowels prior to the test, and you are found to have a full rectum prior to the test then you may require an enema which can be administered prior to the test.
You may continue to take your normal medications prior to the test being carried out. If you have any questions about this then you can discuss this with your doctor prior to the test.

What will happen following the test?

Following completion of the test, the investigator will explain some of the findings with you. However, they will not be able to discuss the results in detail nor will they be able to offer a diagnosis at this time. 
A report will be prepared and sent to your requesting Consultant and you will receive a clinic appointment to discuss your results in full at that time.

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