Flexible sigmoidoscopy is a routine outpatient procedure that is used to look inside the lower part of the gastrointestinal (GI) tract—the sigmoid colon and rectum. This process can help doctors diagnose cancer, unexplained changes in bowel habits, abdominal pain, anal bleeding and weight loss.
Flexible sigmoidoscopy lets the doctor see inside only the sigmoid colon, which is the last part of the colon before the rectum. The procedure takes about 20 minutes. By contrast, a colonoscopy allows the doctor see the entire colon, but takes much longer.
During the Flexible Sigmoidoscopy
During a flexible sigmoidoscopy, the doctor inserts a sigmoidoscope into the anus. The doctor slowly guides the instrument through the rectum and into the sigmoid colon. The sigmoidoscope uses air to expand the colon, helping the doctor to get a better view. A tiny camera mounted on the sigmoidoscope 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 can use the sigmoidoscope to take polyps or samples of the colon tissue (biopsies) while the sigmoidoscope is in the body. After the procedure is over, any biopsies that the doctor takes will be examined under a microscope to check for signs of abnormal tissue. The doctor can also remove any polyps found during the sigmoidoscopy, using miniature tools that are passed into the sigmoidoscope and out the other end. Removal of tissue causes no pain.
If the doctor finds polyps or other abnormal tissue during the sigmoidoscopy, it may be necessary to do a colonoscopy to examine the rest of the colon.
Complications and Risks
You may have some cramps or bloating in the first hour following the procedure. Bleeding and puncture of the large intestine are possible, but these are uncommon complications. Your doctor will give you discharge instructions that you should carefully read and follow.
Possible Side Effects from a Sigmoidoscopy
If you develop any of these rare side effects, you should immediately contact your doctor:
- Severe abdominal pain
- Bloody stools