Flexible Sigmoidoscopy

A flexible sigmoidoscopy allows your doctor to examine the lining of your rectum and the lower part of your colon by inserting a thin, flexible tube with a camera into your anus and advancing it into the rectum and large intestine.  It is a short procedure that can be done in the office without sedation.  It allows the doctor to examine only about 1/3 of the colon, therefore it cannot detect cancer or precancerous polyps that may exist further into the colon.  For that reason, it is most often performed to help diagnose the cause of symptoms such as diarrhea or rectal bleeding.  Although the procedure is not as thorough as a colonoscopy for screening purposes, some elect to have a flexible sigmoidoscopy every five years paired with yearly FOBT testing to screen for colorectal cancer.

What can I expect during a flexible sigmoidoscopy?

As a flexible sigmoidoscopy is less invasive then a colonoscopy, sedation is usually not necessary.  You will lie on your side while your doctor slowly advances then withdraws the scope.  You will lie on your side while your doctor advances the scope through the rectum and part of the colon.  As the instrument is withdrawn, your doctor will carefully examine the lining of your intestine.  You might experience a slight feeling of pressure, bloating or cramping, but the procedure is usually well-tolerated.

What preparation is required?

Your doctor will give you instructions often including a short period of a clear, liquid diet as well as the consumption of an over the counter bowel cleansing solution and completing an enema. In certain circumstances, however, your doctor may omit any special preparation.

What if the flexible sigmoidoscopy shows something abnormal?

There are several painless techniques that use certain special instruments to deal with abnormalities such as polyps or bleeding.  If your doctor sees an area that needs further evaluation, they might take a biopsy (a sample of the colon lining) to be analyzed.  In some cases, a colonoscopy may be necessary to obtain a more thorough examination.

What happens after a flexible sigmoidoscopy?

Although determined on a case-by-case basis, if no sedation was given you should be able to resume a normal diet and your usual activities immediately following the examination.  You may feel bloated or have some cramping at this time because of the air introduced into the colon during the procedure, but it should disappear quickly when you pass gas.  Your physician will explain the results of the examination before you leave, but the results of any biopsies can take up to two weeks.

What are the possible complications of flexible sigmoidoscopy?

Flexible sigmoidoscopies are generally considered very safe. Although uncommon, it’s important to recognize signs of complication. Some rectal bleeding can normally occur for several days after the procedure, but it is important to contact your doctor if it is accompanied by severe abdominal pain or fever and chills. Perforation (or tear) can also occur through the bowel wall, requiring surgery. Minor bleeding might occur at the site of biopsy, but this rarely requires a follow-up.