What is a Flexible Sigmoidoscopy?

Flexible sigmoidoscopy, sometimes shortened to flex sig, allows the physician to examine the inside of the large intestine from the rectum through the last part of the colon, called the sigmoid or descending colon. The colon is five to six feet long. Flexible sigmoidoscopy examines the last one to two feet of the colon.

Why Do I Need a Flex Sig?

Physicians may use this procedure to find the cause of diarrhea, abdominal pain, or constipation. They also use it to look for early signs of cancer in the descending colon and rectum. With flexible sigmoidoscopy, the physician can see 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).

What Are the Benefits of a Flex Sig?

It may allow the physician to make a diagnosis or correct problems during the gastroenterology procedure. Polyps or tumors in the lower portion of the colon can be discovered at an early stage. Conditions such as colitis or diverticulosis may be monitored, and treatment adjusted accordingly.

Is There an Alternative to a Flex Sig?

Yes. Alternative testing includes barium enema X-rays. 

A barium enema does not allow the physician to directly look at the lower colon. In addition, polyps cannot be removed nor biopsies taken during a barium enema.

Are There Side Effects and/or Risks to a Flex Sig?

No test is 100% accurate. Flexible sigmoidoscopy may miss abnormalities that are present because the test only examines the final portion of the colon.  

  • Abnormalities higher in the colon cannot be detected by this test.
  • Temporary bloating is common. 
  • If biopsies are done or if a polyp is removed, there may be bleeding. Bleeding is generally minimal and rarely serious. 
  • Other less frequent complications may include a tear in the wall of the colon which may require surgery.

What Will Happen When I Arrive for My Flex Sig?

  • A brief medical history will be reviewed with you by a nurse.
  • You will provide a list of any current medications you are taking along with any allergies you have to medications.
  • You will be asked to remove your clothing and change into a patient gown.
  • The flexible sigmoidoscopy procedure is most often performed without sedation. However, if your physician has determined that you should receive sedation medication during your procedure, you must have someone to drive you home, or the procedure will not be performed.

What Will Happen During My Flex Sig?

  • The flexible sigmoidoscopy examines only the final portion of the colon. It is generally not painful and usually requires no sedation. If your doctor has chosen sedation for your procedure, an intravenous (IV) catheter will be placed into your arm so that medications can be given for sedation. Most of the effects of the sedation persist for 15-60 minutes, and you may not be able to recall the procedure afterwards.
  • Flexible sigmoidoscopy takes 10 to 20 minutes. For the procedure, you will lie on your left side on the examining table. 
  • The physician will insert a short, flexible, lighted tube into your rectum and slowly guide it into your colon. The tube is called a colonoscope. 
  • 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.
  • During the procedure, you might feel pressure and slight cramping in your lower abdomen. You will feel better afterward when the air leaves your colon.
  • If anything unusual like a polyp or inflamed tissue is identified in your rectum or colon, 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.

What Will Happen After My Flex Sig?

  • In most cases, sedation during flex sig is not required, and you will be able to leave as soon as the procedure is over and the physician discusses the results with you. If you receive sedation, you will remain in the recovery area for one-half to one hour after the procedure, depending on your vital signs and level of consciousness.
  • You may feel bloated from the air used during the procedure. 
  • Following the exam, your physician will discuss the results with you and your loved ones.

How Do I Prepare for My Flex Sig?

Please follow the link below to view the preparations for your Flexible Sigmoidoscopy: