Therapeutic Colonoscopy and Polypectomy

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What is a therapeutic colonoscopy? ​

A therapeutic colonoscopy procedure is an examination of the lining of the colon (large bowel) using a thin flexible, tube-like telescope called a colonoscope. This is carefully passed through the back passage and into the colon which is then used to treat lesions of the colon such as polyps using instruments which are passed through the colonoscope to the site of the target lesion.
A therapeutic colonoscopy is useful for treating certain bowel conditions or as a means of excluding more serious conditions which may be mimicking benign conditions.
Like diagnostic colonoscopy, therapeutic colonoscopy is routinely done as an out-patient or day-case procedure, with no overnight stay. It’s usually performed under sedation to help ensure that you are relaxed and comfortable during the procedure. After sedation, most people have very little memory of the test. 
Your doctor will explain the benefits and risks of having a therapeutic colonoscopy, and will also discuss the alternatives to the procedure. Depending on your symptoms and condition, alternatives may include: 

• Laparoscopic (Keyhole) surgery
• Open (Non-Keyhole) Surgery
• Surveillance

Please see the relevant Cardiff Colorectal information sheet or web pages or feel free to contact us for further information.

What happens during a colonoscopy procedure?

For your doctor to see the lining of your colon clearly, it needs to be completely empty. To achieve this, you will need to follow a special diet for a few days before the procedure and you will be asked not to eat any solids on the day before your examination. You will also be given a laxative, which will come with detailed instructions on how and when to take it. 
If you are having sedation, this may be given through a small plastic tube (cannula) placed in a vein in the back of your hand. You may need oxygen through a mask during the procedure and for a short time afterwards. 
With you resting on your side, your doctor will examine your back passage with a finger before carefully inserting the colonoscope. Lubricating jelly will be used to make this as easy as possible. 
Air will be passed through the tube and into the colon to make the lining easier to see. When this happens, you may briefly feel pains similar to trapped wind. You may also feel that you want to go to the toilet, but as the colon is empty, this will not be possible. You may pass wind, but try not to feel embarrassed, as the staff expect this to happen. 
At the end of the colonoscope, a tiny light and lens allow your doctor to see the lining of the colon. The lining is examined by looking at pictures it sends to a video screen. 
During the procedure, you may be asked to change your position – for example turning from your side onto your back. This helps your doctor to examine different areas of the colon with the colonoscope more easily. 

What therapeutic procedures can be undertaken?

During your colonoscopy several procedures could be performed in order to treat lesions of the lining of the bowel.
These procedures include removing areas of the bowel using several techniques including polypectomy, endoscopic mucosal resection(EMR), hot and cold biopsy and argon plasma coagulation (APC).
Polypectomy and EMR techinques involve the removal of polyps from the bowel lining by using electrosurgery to excise (cut out) the polyps from the lining of the bowel, leaving behind the muscular bowel wall layers. On occasion these areas need to be reinforced by the placement of metal clips into the bowel wall lining and these clips can also be used to stop or prevent bleeding from the polypectomy site. The polyps themselves are then removed from the bowel and sent to the laboratory for further analysis. Some polyps if left within the bowel may eventually become cancerous growths hence the need to deal with these lesions early to prevent the need for more extensive treatment at a later date.
Hot and cold biopsies are used for the removal of smaller polyp lesions or for the sampling of polyps where immediate treatment is not going to be carried out because of concerns about the true nature of the polyp.
Argon plasma coagulation can be used to treat areas of bowel wall that are prone to bleeding to prevent them from bleeding in the future. In APC a stream of argon gas is superheated to form a plasma and this plasma stream coagulates the bowel wall surface, destroying the abnormal tissue and removes the abnormal blood vessels which cause the bleeding. It can also be used to destroy residual polyp tissue around the edges of a polypectomy site.

What are the risks of a therapeutic colonoscopy?

Therapeutic colonoscopy is a commonly performed and generally safe procedure. For most people, the benefits of having a minimally invasive treatment are much greater than any disadvantages. However, like all medical procedures, there are some risks.
Your doctor will be experienced at performing therapeutic colonoscopies but even so, occasionally a colonoscopy is not completed successfully and may need to be repeated. 
Other complications are uncommon. It’s possible for the colon to be damaged or, in very rare cases, perforated during the procedure (1 in 1000 cases). This can lead to bleeding and infection, which may require treatment with medicines or surgery. 
There are also risk associated with the administration of sedative medications including a risk of allergic reactions and a risk of problems with breathing and blood pressure during sedation.
The chance of complications depends on the exact type of procedure you are having and other factors such as your general health. Ask your doctor to explain how any risks apply to you.

​Further information can be found in the downloads section of this website.