A flexible sigmoidoscopy is a visual examination of the inside of the rectum and lower part of the colon.
While you lie on your side, a flexible tube about the thickness of a finger called a sigmoidoscope is inserted into the anus and slowly advanced into the rectum and lower part of the colon. As your doctor withdraws the instrument, your doctor will carefully examine the lining of the intestine.
Your physician will explain the results to you when the procedure is done. Flexible sigmoidoscopy is usually well-tolerated, but you might feel bloating or some mild cramping because of the air that was passed into the colon during the examination. This will disappear quickly when you pass gas. You should be able to eat and resume your normal activities after leaving your doctor’s office or the hospital, assuming you did not receive any sedative medication.
In general, preparation consists of one or two enemas prior to the procedure but could include laxatives or dietary modifications as well. Your doctor will tell you what cleansing routine to use. However, in some circumstances your doctor might advise you to forgo any special preparation. Because the rectum and lower colon must be completely empty for the procedure to be accurate, it’s important to follow your doctor’s instructions carefully.
Most medications can be continued as usual. Inform your doctor about medications that you’re taking, particularly aspirin products or anticoagulants (blood thinners), as well as any allergies you have to medications. Also, tell your doctor if you require antibiotics prior to dental procedures, because you might need antibiotics prior to sigmoidoscopy as well.
If your physician sees an area that needs further evaluation, your doctor might take a biopsy to be analyzed. Biopsies are used to identify many conditions, and your doctor might order one even if he or she doesn’t suspect cancer.
Your doctor might also find polyps during sigmoidoscopy, and he or she will most likely remove them during the examination. Polyps are abnormal growths in the colon lining that are usually benign (non-cancerous). They vary in size from a tiny dot to several inches. Because cancer begins in polyps, removing them is an important means of preventing colorectal cancer. Polyps are removed with either biopsy instruments or by passing an electrical current through small wire loops called “snares,” a procedure that should be pain free.
Polyps known as “hyperplastic” might not require removal, but benign polyps known as “adenomas” are potentially pre-cancerous. Your doctor can't always tell a benign polyp from a malignant (cancerous) polyp by its outer appearance, so he or she might send removed polyps for further analysis. Your doctor might also ask you to have a colonoscopy (a complete examination of the colon) to remove any large polyps or any small adenomas.
Flexible sigmoidoscopy and polypectomies are generally safe procedures when performed by specially trained and experienced doctors. Although complications after this procedure are uncommon, it’s important to recognize early signs of possible complications.