Flexible sigmoidoscopy is a procedure used to see inside the sigmoid colon and rectum. Flexible sigmoidoscopy can detect inflamed tissue, abnormal growths, and ulcers. The procedure is used to look for early signs of cancer and can help doctors diagnose unexplained changes in bowel habits, abdominal pain, bleeding from the anus, and weight loss.
Flexible sigmoidoscopy enables the doctor to see only the sigmoid colon, whereas colonoscopy allows the doctor to see the entire colon. Colonoscopy is the preferred screening method for cancers of the colon and rectum; however, to prepare for and perform a flexible sigmoidoscopy usually requires less time.
During a flexible sigmoidoscopy, you will lie on your left side on an examination table. The doctor inserts a long, flexible, lighted tube called a sigmoidoscope, or scope, into your anus and slowly guides it through your rectum and into the sigmoid colon. The scope inflates the colon with air to give the doctor a better view. A small camera mounted on the scope transmits a video image from inside the colon to a computer screen, allowing the doctor to carefully examine the tissues lining the sigmoid colon and rectum. The doctor may ask you to move periodically so the scope can be adjusted for better viewing.
When the scope reaches your transverse colon, the scope is slowly withdrawn while the lining of your colon is carefully examined again.
The doctor can remove growths, called polyps, during flexible sigmoidoscopy using special tools passed through the scope. Polyps are common in adults and are usually harmless. However, most colon cancer begins as a polyp, so removing polyps early is an effective way to prevent cancer. If bleeding occurs, the doctor can usually stop it with an electrical probe or special medications passed through the scope.
During a flexible sigmoidoscopy, the doctor can also take samples from abnormal-looking tissues. Called a biopsy, this procedure allows the doctor to later look at the tissue with a microscope for signs of disease.
Tissue removal and the treatments to stop bleeding are usually painless. If polyps or other abnormal tissues are found, the doctor may suggest examining the rest of your colon with a colonoscopy. Flexible sigmoidoscopy usually takes about 20 minutes.
Cramping or bloating may occur during the first hour after the procedure. Bleeding and puncture of the large intestine are possible but uncommon complications. Discharge instructions should be carefully read and followed.
Reprinted and modified from The National Digestive Diseases Information Clearinghouse