Flexible sigmoidoscopy

What Is flexible sigmoidoscopy?

A flexible sigmoidoscopy is a short colonoscopic examination limited to the rectum and the lower 40-50cm of the large bowel. It is performed by means of a flexible tube (colonoscope), whichin which thousands of tiny glass fibres transmit light to the tip where a tiny camera takes images of the bowel lining and sends them to a video screen. If polyps or other abnormalities are seen, a sample can be taken for examination by the pathologist.

Why would I need a flexible sigmoidoscopy?

Flexible sigmoidoscopy may be recommended for the colon:

  • To look for causes of blood loss from the bowel
  • To assess the extent of inflammation of the colon
  • For screening purposes in people without symptoms to look for polyps or colon cancer
  • To see if the bowel has been affected by endometriosis
  • Following colon surgery to check the bowel and any joins made in it.

Generally, if you are over 50, a full colonoscopy will be more appropriate than the more limited flexible sigmoidoscopy.


Flexible sigmoidoscopy is carried out in the consulting rooms after administration of an enema to clear the lower bowel. It typically takes about 5-10 minutes. It is not a painful procedure although some discomfort may be felt when air is introduced into the bowel or as thecolonoscope is maneuvered around the corners of the bowel. Sedation or pain relief are not usually necessary.

After the procedure, the results will be discussed with you and any samples taken will be sent to the laboratory. A report is usually available shortly afterwards and a copy will be sent to your general practitioner.


Flexible sigmoidoscopy is a very safe procedure, and complications are rare. However, as with any diagnostic procedure there are potential risk factors to be considered:

  • Bleeding — this can occur with any type of biopsy
  • Perforation of the bowel — this may require surgical intervention. This occurs in less than 1 in 10,000 cases.

Follow Up

If during the procedure abnormalities such as polyps or bowel cancer are seen, then it is likely that the rest of the bowel will need examination. This is usually performed by means of a full colonoscopy which is performed at a later time, after a full bowel preparation. Sometimes, if the enema has produced particularly effective clearance of the colon, it may be appropriate to simply continue the flexible sigmoidoscopy examination to a full colonoscopy at the time.

If you do have a polyp you are in a high-risk group and are more likely to develop additional polyps. After a polyp is removed you are advised to have your colon examined again at regular intervals.

How do I get a referral?

Your GP can refer you for a flexible sigmoidoscopy or you may contact us directly to make an appointment.