Flexible sigmoidoscopy is a procedure that enables your physician to examine the lining of the rectum and a portion of the colon (large bowel) by inserting a flexible tube that is about the thickness of your finger into the anus and advancing it slowly into the rectum along the length of the lower part of the colon.

The rectum and lower colon must be completely empty of waste material for the procedure to be accurate and complete. Your physician will give you detailed instructions regarding the cleansing routine to be used. In general, preparation consists of one or two enemas prior to the procedure but may include laxatives or dietary modifications. In some circumstances, for example, if you have acute diarrhea or colitis, your physician may advise you to forego any special preparation before the examination.

Most medications can be continued as usual. You should inform you physician of all current medications as well as any allergies to medications or latex several days prior to the examination. However, drugs such as aspirin or anticoagulants (blood thinners) are examples of medications whose use should be discussed with your physician.

Flexible sigmoidoscopy is usually well tolerated. However, there is a feeling of pressure, bloating, or cramping during the procedure. In some cases your physician may give you medication through a vein to help you relax and better tolerate any discomfort from the procedure. You will be lying on your left side or on your back while the colonoscope is advanced slowly along the length of the rectum and sigmoid colon. As the instrument is withdrawn, the lining of the intestine is carefully examined. The procedure usually takes anywhere from 5 to 15 minutes.

If the physician sees an area that needs evaluation in greater detail, a biopsy (sample of the colon lining) may be obtained and submitted to a laboratory for further analysis. If polyps (growths from the lining of the colon) are found, they may be biopsied but are generally not removed at the time of the sigmoidoscopy. Your physician will likely request that you have a colonoscopy (a complete examination of the colon) to remove any large polyps that are found, or any small polyps that are found to be adenomatous after biopsy analysis.

After sigmoidoscopy, the physician will explain the results to you. You may have some mild cramping or bloating sensation because of the air that has been passed into the colon during the examination. This will disappear quickly with the passage of gas. You should be able to eat and resume your normal activities after leaving your physician’s office or the hospital.

Flexible sigmoidoscopy and biopsy are generally safe when performed by physicians who have been specially trained and are experienced in these endoscopic procedures. Complications after flexible sigmoidoscopy are rare. It is important for you to recognize early signs of any possible complication. Immediately contact your physician if you notice any of the following symptoms: severe abdominal pain, fevers and/or chills, or rectal bleeding of more than 1/2 cup. It is important to note that rectal bleeding can occur even several days after the biopsy. Small amounts of bleeding are not unusual after sigmoidoscopy, especially if one or more biopsies are taken.