Flexible Sigmoidoscopy

Introduction

What is it?

A flexible sigmoidoscopy is a procedure that examines the lower part of the Colon. The Colon is the lower part of the gastrointestinal tract. 

It uses a flexible endoscope, a small tube with a camera and a light on its end, to look inside the colon for any issues. It is commonly done to help diagnose a problem you may have had with your bowels, such as bleeding from the back passage or change in bowel habit, or to screen for colon cancer in people over 50. This procedure will be carried out by a specialised doctor (an endoscopist) and his team. 

Why is it done?

This procedure allows your doctor to gather information about the colon that would not be available otherwise by simple examination or through imaging. It also allows to take small tissue samples from your colon that can be further investigated. 

Colon Cancer screening

A further benefit of flexible sigmoidoscopy is that can be used to screen for colorectal cancer; it is shown to reduce mortality from colorectal cancer since its introduction as a method of screening.

However, 41 to 45 percent of Colon cancer occurs on the right side of the colon which is not looked at using Sigmoidoscopy (1). The risk of having right sided cancer increases with age and also for females compared to males.

Many cancers develop from polyps (growths into the middle of the bowel on stalks). In caucasians the percentage of polyps in the right colon is around 30%, this number is higher in blacks (2).

Sigmoidoscopy is more effective in men than women, perhaps because women have a greater occurrence of right sided colon cancer. A study reports that 66 of men would have had advanced polyps or colon cancer detected by Sigmoidoscopy whereas only 35% of women would (3)

Will I need to do any preparation?

Prior to the Flexible Sigmoidoscopy, you will need bowel preparation. This bowel preparation is less involves and less invasive than that required for full colonoscopy. Good preparation will also allow the endoscopist to see the whole colon, so that the procedure is performed adequately. It is important to read the list of detailed instructions you will be given by your doctor ahead of time and follow them carefully.

The lowest part of the bowel must be cleaned out to allow the endoscopist to see the inside lining. This is generally referred to as “bowel cleaning” or bowel preparation. Most commonly two phosphate ememas are sufficiency to clear the bowel sufficiently (4).  Phosphate enemas may cause disturbances in the electrolyte (salt) levels in the blood particularly in the elderly. For older people (5,6)

Some medications you are already on may need to be stopped before the operation. If you are taking blood thinning medications (such as Warfarin), check with your doctor whether you should stop taking it temporarily (7). Medications for diabetes may also need to be adjusted before the procedure. Iron tablets must be stopped as iron coats the colon lining, making it difficult to see. Most other medications should be fine; just check with your doctor beforehand.  

Technique

Anaesthesia

As this is a short procedure, and discomfort is mild, sedation and pain medications are generally not required.

What does it involve?

The procedure usually takes 10-15 minutes. You will be told to lie on your left side with your knees tucked up to your chest. The sigmoidoscope, which is about the size of a finger (1 cm wide), is inserted into the anus and advanced into the rectum and sigmoid colon. The sigmoidoscope has a camera and a light source on it, so the endoscopist will be able to see the inside of the colon on a monitor (8). 

The endoscope can be used to take small samples of tissue if the doctor sees anything unusual. This should not hurt, as the lining of the colon does not sense pain. Additionally, the endoscope can blow air into the colon. This will allow the endoscopist to get a better view.  You may feel some cramping as air enters the colon, and it may help to release air through your rectum to decrease the discomfort.

The endoscopy team should get back to you as soon as the results are available. 

Post procedure course (follow-up)

Most patients tolerate the procedure well and are able to return to their normal activities afterwards. In most cases, you can go to work and drive the same day (given that you do not take any medications, such as sedatives, that would interfere). 

How long will I stay in hospital?

The procedure is either 'office based' or day case. No inpatient stay is required.

What care will I need at home?

No particular care is required

Will I need someone to stay with me?

As sedation is not usually give, you will not need someone to stay with you.

Will I need any special equipment when I go home?

No special equipment required.

What follow up care is needed? 

Follow up with your healthcare specialist is required to ensure that you have had appropriate investigation of your bowel. Flexible sigmoidoscopy is often combined with other tests to visualise the Right side of the Colon.

If visualisation of the colon was not possible then the test should be repeated within 3 months particular if the test was done for screening purposes (9,10,11).

If the flexible sigmoidoscopy is positive for a suspicious area then a full colonoscopy is required to investigate the rest of the Colon.

When can I start my normal activities again (e.g. driving, sports or work?)

Can restart as soon as comfort allows.