A flexible sigmoidoscopy is a diagnostic procedure performed to examine the sigmoid colon, the last one-quarter of the colon. A flexible sigmoidoscopy procedure can aid in determining the cause of changes in bowel activity, abdominal pain, and rectal bleeding, as well as detecting colon cancer. A flexible sigmoidoscopy may be recommended as an option for people age 50 and older who are at risk of developing colon or rectal cancer, although colonoscopy provides a more thorough evaluation.
During a flexible sigmoidoscopy, a long, thin, flexible tube with a camera in the end of the tube, called a sigmoidoscope, is inserted into the sigmoid part of the colon through the anus. Images of the rectum and sigmoid colon are displayed on a screen for the doctor to examine and detect any abnormalities. The removal of polyps, or growths, for biopsy may also be conducted during the procedure. Laxatives, dietary restrictions, and sometimes enemas are used to clean out the colon. A sigmoidoscopy usually takes 20 minutes to perform. Sedation may or may not be used during the sigmoidoscopy. Some people may experience pressure, bloating and cramping in the abdomen during or after the procedure, but these effects are temporary. Rare complications may occur (see section on Colonoscopy). If certain abnormalities, such as colon polyps, are found, colonoscopy, a more thorough examination of the colon may be required.