A series of diagnostic tests are used to measure the strength of the anal sphincter muscles, the nerves serving the muscles, the integrity of the muscles, the mechanics of defecation, and the rate of transit through the colon.
Anorectal manometry tests the sensation in the anal/rectal area, the tone of the anus at rest, the voluntary squeeze, anorectal reflex, and the elasticity of the rectum. This test is performed using a small tube inserted into the anus and rectum.
Using an ultrasound probe inserted into the anus, sound waves mark an array of points that are converted to an image seen on a video monitor. Viewing the pictures allows the doctors to see the integrity of the sphincter muscles. The ultrasound is also used in the rectum to measure the depth of growth of the tumors.
Pudendal Nerve Test
The pudendal nerves run on each side of the pelvis, and control bladder function, sexual function, and bowel sphincter muscles. This test checks the electrical conduction of the pudendal nerves. It is performed using special electrodes on the gloved, index finger pressed against the nerve site. This test is done in the office.
This is a test to view the mechanics of emptying the rectum. This test is performed in the radiology department. Prolapse and rectocele (bulging) are easily seen.
Colonic Transit Time Study (Sitz Marker Study)
20 markers are taken in a capsule on day 1. The markers can be seen on standard abdominal X-rays taken on days 4 and 7 so that the markers can be timed by their travel through the bowel.