Anorectal Physiology
What is Anorectal Physiology?
Anorectal physiology is the study of the function of the anus and rectum. It is a computer-assisted method whereby muscle strength and pelvic floor motion are evaluated. This evaluation of patients with disorders of bowel function will help your physician recommend appropriate medical or surgical treatment to you. The tests are explained below. In addition, some patients’ evaluation requires x-ray studies which are also explained below.
What tests are performed?
Several different tests may be performed. You may be scheduled for only one or several of the tests. The doctor should already have explained to you which tests are to be performed. If you are unclear about which tests you are having or have other questions not answered below do not hesitate to call the office and speak with the doctor’s medical assistant.
When will I know the results?
In most cases the doctor will discuss your results immediately following the conclusion of the tests. However, if there are other tests pending for your evaluation, such as completion of a defecography or pelvic MRI, the doctor will need to compile all that data together with your anorectal physiology tests before being able to reach a conclusion and make recommendations as to treatment. In this case the patient will be asked to return for another office visit after all the tests are completed.
Anal Manometry
Anal Manometry is an evaluation of the strength of the muscles which control your bowel movements. The test is performed by placing a small tube (about the size of a drinking straw) into the rectum. Pressure monitors inside the tube measure muscle strength which is recorded on a computer graph similar to an electrocardiogram (EKG). A measure of rectal sensation will also be obtained. It is a painless procedure which takes about 10 minutes to perform.
Electromyography (EMG)
Electromyography (EMG) tests the electrical activity of the pelvic floor muscles when the patient squeezes them or pushes to defecate. It is performed by placing two small sticky electrodes on the skin surface just outside the anal opening. There is no electrical shock given or felt. The patient is asked to squeeze the sphincter muscles and then to push as if they were having a bowel movement. The degree to which the muscles generate an electric impulse is measured by the computer. This is a painless procedure and takes just a few minutes to do.
Pudendal Nerve Testing
The pudendal nerve is the nerve that innervates the anal sphincter muscle and must work correctly for the muscle to squeeze appropriately. This test is most commonly used to evaluate problems with incontinence. It is performed using a small sensor placed on the tip of a gloved finger and is inserted into the rectum. This is much the same as having a rectal exam. A tiny amount of electrical stimulation is given through the electrode at the finger tip. The patient does not feel any electric shock but may feel the sphincter muscle twitch slightly. This test is not painful and takes about 10 minutes to perform.
Anorectal Ultrasound
Rectal ultrasound is a painless procedure designed to evaluate the anal sphincter muscle. A short ultrasound probe (about the width of a finger) is inserted into the anus and sound waves are bounced off the muscle giving the doctor a precise anatomic picture of the muscle. It is most commonly used in patients with incontinence to locate any sphincter interruption. The examination takes about 10 minutes to perform.
How long does it take?
Between 20 and 30 minutes. If you are not scheduled for all the tests, then it will take less time. No medications are given. You may leave immediately after the tests are performed.
How do I Prepare for the exam?
You will need to take two regular fleet enemas (in the green and white bottles available at any pharmacy). Take the first enema two hours before leaving for the exam and the second one hour before leaving. There are no dietary restrictions. Please arrive 10 minutes prior to your scheduled appointment.
What if I need to cancell my appoinment?
Substantial office time and equipment are set aside for these appointments so it is imperative that the office be notified three days in advance if you can not keep the appointment. You will be charged $100.00 if we are not given 3 days notice for canceling and/or rescheduling this appointment for non medical reasons.
Defocography
Defocography is a x-ray test of the function of the rectum and pelvic floor muscles. These muscles control the rectum and anus during evacuation and are responsible for the control of bowel movements. This test is done at INOVA Fairfax Hospital. At the time that this test is ordered, our office will give the patient a VHS tape to take with them to the test. You will be asked to drink a small amount of barium. A small amount of barium paste is place into the rectum and vagina. An X-ray recording is made on the VHS tape during evacuation of the paste. This painless test is administered by a Fairfax Hospital Radiologist and takes about 15 minutes to perform. Please drop the VHS tape off at our Fairfax Office on your way home. Your surgeon will review the tape prior to your next appointment.
Dynamic Pelvic MRI
Dynamic Pelvic Floor Magnetic Resonance Imaging is a test used to evaluate pelvic floor function. The MRI scan can detect changes in the pelvic floor musculature, as well as changes in the position of the small intestine, bladder, uterus, and rectum, which may be responsible for some of the problems with defecation or incontinence. Although no x-rays are used, the test is similar to a CT scan. The test is painless and takes about 15 minutes. No preparation of the bowel is required for the test. A small amount of contrast will be inserted into the rectum at the time of the test. This test is performed at the Fairfax MRI Center located at 8318 Arlington Blvd in Fairfax.