What is Sigmoidoscopy?

Sigmoidoscopy, or flexible sigmoidoscopy, is an endoscopy procedure that uses a long flexible tubular instrument with light source, inserted via the anus, to assess the lining of the left colon or the left side of the large intestine so we can examine for any abnormalities in that region. 

It is done as a Day Surgery procedure and it takes about 15-20 minutes approximately. It is done under moderate sedation, which means that the patient will be given medications into the vein to make them feel relaxed, painless and drowsy. It is also possible to do the procedure under local anaesthesia.

During the scope, air is blown into the colon and helps us to see more clearly, which may cause mild abdominal discomfort but will resolve. We will examine the colon as the scope is slowly withdrawn and will do procedures (which may include biopsy or polypectomy) as required depending on what we find.

What are the most common reasons for this procedure?

  • Blood in stools or bleeding per rectum in young patients which is persistent and who are low-risk for cancer
  • Abnormal imaging study of the left colon (to do a polypectomy or biopsy or to assess that part of the colon)
  • Short-term surveillance of high-risk polyp removed from the left colon
  • Screening of cancers, most commonly occurring in the sigmoid colon
  • It can be combined with rubber band ligation of piles, or hemostasis of radiation proctitis

What should the patient do before the procedure?

The patient should fast overnight, prior to the procedure. They should also avoid high-fiber diet for three days before the scope.

On arrival, an enema will be given at the endoscopy center (to clear the stools).

Meanwhile, please inform us about any specific medical conditions the patient has (e.g. diabetes, hypertension, heart valves, blood thinner medications, etc.), since that will require more special instructions.

What should the patient do after the procedure?

Immediately after the scope, we will observe the patient in the recovery room and monitor them closely. If certain procedures were done during the scope, then certain medications have to be held off temporarily – which we will clearly instruct before discharging the patient.

If biopsy or polypectomy were done, then the histology/results of the same will have to be traced at the next clinic visit.

Patients may feel some cramping or bloatedness, which will resolve quickly once they start passing gas.

We will recommend that the patients arrange for a family member or a driver to bring them back home after the scope, since it is unsafe to drive or operate any machinery for about 8-12 hours after the procedure due to the sedation medication given during the procedure. However, if the procedure is done under local anesthesia, the patient can go home alone on their own. Patients can also resume a normal diet after recovery.

Are there complications that might arise from this procedure?

Some patients might experience abdominal cramps or bleeding, especially when biopsy or polypectomy is done. A very small number of patients might also experience perforation of the bowel.

However, the incidence of the above complications is very low – about one in 1,500 to 2,000 – and if it happens, then the patient may require emergency surgery. While it may be catastrophic, the procedure is overall considered to be safe in experienced hands.

Do note that in about 2-3% of the patients, it may be technically difficult to complete the scope due to anatomical reasons and/or poor bowel preparation. For such patients, we may have to arrange for alternative imaging techniques, such as CT Colonography. They can also opt to repeat the scope another day.

What should the patient expect a few days after the procedure?

During the patient’s next clinic visit, we will provide them with scope pictures taken during the procedure, as well as some histology report, and proceed with further management. Depending on the findings, we might also recommend follow-up scopes in specified intervals.