Flexible Sigmoidoscopy

A sigmoidoscopy is a minimally invasive diagnostic procedure that gathers information on intestinal symptoms and looks for the presence of abnormal tissue in the lower part of the colon (rectum and sigmoid colon). 


A thin, flexible tube (sigmoidoscope) is inserted into the rectum. A tiny video camera at the tip of the tube allows the doctor to view the inside of the rectum, the sigmoid colon and most of the descending colon — just under the last 2 feet (about 50 centimeters) of the large intestine. If necessary, tissue samples (biopsies) can be taken through the scope during a flexible sigmoidoscopy exam.

Who would benefit from a sigmoidoscopy? 

  • Colon Cancer Screening: – It is important to note, that while this is used as a colon cancer screening tool, sigmoidoscopy does not allow the doctor to visualize your entire colon. This would typically be done every 5 years, after the age of 45yrs. Screening may start at a younger age if there is a family history of colon cancer. 
  • To investigate certain symptoms such as rectal bleeding, chronic diarrhea and abdominal pain. 
  • To review an area in the lower colon that had abnormal findings on imaging, or prior endoscopic evaluation (eg. To review an area where a polyp was removed)

What preparation is required?

Ideally, consume a low residue (low fibre) diet 2 days before the procedure. Do not eat beans, vegetables, corn, potato skin, nuts or seeds. These foods may stick to the folds of the colon, both interfering with adequate colon preparation and potentially getting sucked into the sigmoidoscope during the procedure, clogging the instrument. Nothing solid to eat after midnight prior to the date of the procedure. You will be asked to take 2 fleet enemas 2 hours prior to the procedure, in order to empty the lower colon. 

Certain medications may also need to be adjusted; so let the doctor know what you are taking. Blood thinners ideally should be held, once safe to do so. The timing of this will be advised by the physician. Do not take oral diabetic medication on the morning of the procedure. You can take your antihypertensives with a sip of water, up to 4 hrs prior to the time of the procedure. 


The adequacy of the preparation has a direct impact on the quality of your procedure. Kindly follow all instructions given and contact our office if you have any queries or concerns. The procedure may need to be cancelled or repeated earlier than needed if the bowels are inadequately prepared.


A Sigmoidoscopy is typically done in an endoscopy suite. FOSA has a recently furnished suite with state of the art equipment to facilitate this procedure under optimal conditions.  Your heart rate, blood pressure, respiratory rate, and oxygen level will be monitored throughout your procedure. You will have a pulse oximeter placed on your finger that measures oxygen saturation and pulse, and a blood pressure cuff will be placed on your arm.

You will then be positioned so that you lie on your left side. The procedure typically does not require sedation. However, it can also be done under conscious sedation, where intravenous medication is given to make you comfortable. The procedure may take about 15-20 minutes, depending on how well the bowel is prepped and what is found during the investigation. Once you are comfortable the scope is gently placed into the rectum and advanced to the sigmoid colon. A detailed evaluation of the mucosal lining is done and an appropriate assessment made.

During the procedure: 

  • Biopsies may be taken from the mucosa, if indicated. 
  • In the event of bleeding lesions, such as ulcers, therapeutic measures can be undertaken at the same time to treat the area. 
  • If a polyp (pre-cancerous) lesion is found these can be removed at the same time

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Normal Colon                                 Inflamed Colon                                                                                    


Polyp being removed (Polypectomy)

What to expect after the procedure?

You will be able to leave shortly after the procedure if no sedation is given. If you did receive sedation, you will have to remain for approximately 30 mins after the procedure to monitor vital signs and ensure you are alert prior to leaving. 

Air is used to distend the colon to allow for visualization of the bowel walls. This may lead to some bloating and abdominal discomfort. This is usually easily passed out as flatulence. It is recommended therefore that you have comfortable clothing to put on after the procedure that won’t restrict your abdominal area. 

Often times, a biopsy may be taken of the mucosal lining. This will be sent to a pathologist for further evaluation. The results of this will typically be available a few weeks after submission. Your doctor will advise you of the results thereafter. 

You will be able to resume your regular diet after the procedure.

A sigmoidoscopy is a relatively quick procedure and is generally well tolerated. Please feel free to contact our office at FOSA if you are experiencing lower GI symptoms and need evaluation.