Flexible Sigmoidoscopy

A flexible sigmoidoscopy is an internal exam of the lower part of the large intestine (colon) using a short, thin, flexible lighted tube. The tube, called a flexible sigmoidoscope, has a tiny camera at the tip allowing the doctor to view the inside of the rectum and the sigmoid colon—about the last two feet of the large intestine. A flexible sigmoidoscopy can help your doctor determine the cause of abdominal pain, rectal bleeding, changes in bowel habits, chronic diarrhea and other intestinal problems.

The lower colon and rectum must be completely empty for a flexible sigmoidoscopy to be thorough and safe. Some doctors recommend a combination of a laxative and an enema before the test. Some doctors may advise the patient to drink only clear liquids for 12 to 24 hours before the procedure is scheduled. The night before, or even immediately before the flexible sigmoidoscopy, the patient may be given an enema, which is a liquid solution that washes out the lower intestine.

During the test, the patient is positioned on the left side with knees drawn up toward the chest. First, the doctor will do a digital rectal exam by gently inserting a gloved and lubricated finger into the rectum to check for any abnormalities.

Next, the sigmoidoscope is inserted into the rectum, and the patient will feel some pressure. Air is introduced through the scope to expand the colon and help the doctor see adequately. As the scope is slowly removed, the lining of the bowel is carefully examined. A hollow channel in the center of the scope allows for the passage of an instrument called a forceps for obtaining a biopsy if needed.

You and your doctor will discuss the results of your flexible sigmoidoscopy. The exam is considered negative if the doctor does not find any abnormalities. A positive exam might identify polyps or abnormal issue in the colon. Depending on the findings, you may need additional testing, such as a colonoscopy, so that the entire colon can be examined.