Flexible Sigmoidoscopy

Flexible Sigmoidoscopy enables the doctor to look at the inside of the large intestine from the rectum through the last part of the colon, called the sigmoid. Doctors may use the procedure to find the cause of diarrhea, abdominal pain, or constipation. They also use it to look for benign and malignant polyps, as well as early signs of cancer in the descending colon and rectum. With flexible sigmoidoscopy, the physician can see intestinal bleeding, inflammation, abnormal growths, and ulcers in the descending colon and rectum. Flexible sigmoidoscopy is not sufficient to detect polyps or cancer in the ascending or transverse colon (two-thirds of the colon). However, although in absolute terms only a relatively small section of the large intestine can be examined using sigmoidoscopy, the sites which can be observed represent areas which are most frequently affected by diseases such as colorectal cancer, for example the rectum.

For the procedure, the patient must lie on his or her left side on the examining table. The physician inserts a short, flexible, lit tube into the rectum and slowly guides it into the colon. The tube is called a sigmoidoscope. The scope transmits an image of the inside of the rectum and colon, so the physician can carefully examine the lining of these organs. The scope also blows air into these organs, which inflates them and helps the physician see better.

If anything unusual is in the rectum or colon, like a polyp or inflamed tissue, the physician can remove a piece of it using instruments inserted into the scope. The physician will send that piece of tissue (biopsy) to the lab for testing.

Bleeding and puncture of the colon are possible complications of sigmoidoscopy. However, such complications are uncommon.

Flexible sigmoidoscopy takes 10 to 20 minutes. During the procedure, the patient might feel pressure and slight cramping in the lower abdomen, but he or she will feel better afterward when the air leaves the colon.