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Flexible Sigmoidoscopy

What is a flexible sigmoidoscopy?

A flexible sigmoidoscopy is a test which allows Dr Maiden to look directly at the lining of the left side of the colon (large bowel). A long flexible tube about the width of your finger is inserted into the back passage (anus). The tube is passed around the lower part of the colon and pictures are displayed on a television screen allowing Dr Maiden to detect any abnormal areas. Tissue samples (a biopsy) can be taken and sent to the laboratory for analysis. Polyps (abnormal growths) can also be removed during the procedure and sent for analysis.


The test takes approximately 10 to 15 minutes to complete but it can take a little less and in some cases longer than this. You could be in the department for around 1 hour to allow for check in and the recovery period following your procedure.


The test can be uncomfortable at times as air is blown into the bowel; most people tolerate the procedure well without the need for sedative medication. However, there is the option to have a sedative for those people who think they may need it. This is not a general anaesthetic therefore you will not be asleep. The sedative will help to relax you but you will still be able to feel sensations, hear what we say to you and follow simple instructions during the test. You may not remember anything about the test afterwards due to the sedation, but this cannot be guaranteed. The sedation can stay in your system for up to 24 hours. You will not be able to drive, drink alcohol, sign legal documents, operate machinery or look after small children during this time. A responsible adult must collect you from the endoscopy unit, take you home and stay with you for 24 hours after the procedure.


What are the risks?

Flexible sigmoidoscopy is an established and safe procedure but very rarely it can result in complications. Some of these can be serious though rare.

Breathing difficulties or heart irregularities, as a result of reacting to the sedation or the bowel being stretched. To help prevent this from happening, your oxygen levels and heart rate will be monitored.  

Making a hole in the colon (risk: less than 1 in 1,000). The risk is higher if a polyp is removed (risk: less than 1 in 500). This is a serious complication. You may need surgery which can involve forming a stoma (bowel opening onto the skin).

Bleeding from a biopsy site or from minor damage caused by the endoscope (risk: less than 1 in 1,000). This usually stops on its own.

Bleeding, if a polyp is removed (risk: 1 in 100). Bleeding usually stops soon after a polyp is removed. Sometimes bleeding can happen up to two weeks after the procedure. Let Dr Maiden or the nurse know if you are on Warfarin, Clopidogrel or other blood-thinning medication. You may need to stop your medication before having a polyp removed.

Incomplete procedure. This can happen due to a technical difficulty, blockage in the large bowel, complications during the procedure or discomfort. Your doctor or Dr Maiden may recommend another procedure or a different test.


Alternatives to this test

There are alternatives to this test e.g. x-ray examinations, however the disadvantage of these tests is that specimens cannot be taken and if an abnormality is seen, you may still need to have this test performed.