A sigmoidoscopy – also called a flexible sigmoidoscopy because of the flexible tube used in the procedure – is an examination of the lower 20 inches of the colon known as the sigmoid colon.

How Is a Sigmoidoscopy Performed?

To perform a sigmoidoscopy, the doctor inserts a lighted, flexible tube about the thickness of a finger through the rectum then into the lower portion of the colon to examine the lining of the lower colon for any abnormalities.

Before beginning the procedure, which takes place at one of our four procedures units locations, you will be asked to lie on your left side. The doctor will gently insert the lubricated tube. As the scope passes through the curves of your colon, you may feel some pressure or discomfort. The nurse will encourage you to breathe slowly and deeply to ease any discomfort. The doctor will put air into your colon in order to see the lining. You may have some mild bloating or abdominal discomfort from the air. You may feel like you need to have a bowel movement. The doctor will remove as much air as possible after the procedure. Because the exam is usually quick and simple, most patients do not require sedation.

The procedure takes about 20 minutes, but expect your visit to last at least 1 hour, which includes time for preparation and follow-up with the doctor. 

A sigmoidoscopy requires an enema before the test to clean out the lower part of the colon about an hour before the procedure.

Why Do I Need a Sigmoidoscopy?

A sigmoidoscopies help your doctor rule out possible conditions or make a diagnosis for issues such as:

If necessary, during the procedure an instrument can be passed through the tube to take a small piece of tissue (a biopsy) for examination in the lab. Biopsies are done for many reasons and do not necessarily imply cancer. Other procedures can be performed if necessary during the sigmoidoscopy, such as removing a polyp.

What’s the Difference Between a Sigmoidoscopy and a Colonoscopy?

While a sigmoidoscopy only examines the lower 20 inches of the colon, a colonoscopy examines the entire colon. A colonoscopy is performed under mild sedation, but a sigmoidoscopy generally requires no sedation.

What Are the Potential Complications from a Sigmoidoscopy?

Complications are extremely rare but can include a colon infection, bleeding due to damaging the wall of the colon, and piercing the colon. All complications will be explained to you at the time you sign your consent for the procedure.

What Happens After the Sigmoidoscopy?

After the procedure, you will be taken to a recovery area so you can change into your clothing and receive discharge instructions. You will be able to drive yourself home if you do not receive sedation. If you want to bring a family member or friend with you, a comfortable waiting area is available.

The preliminary results will be explained to you and the complete results are given to the doctor who ordered your procedure.

Make an Appointment

To make an appointment for a sigmoidoscopy or other GI procedure, call the University of Michigan Medical Procedures Unit at 877-758-2626.