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 anesthesia.

During the scopy, 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 We will examine the colon as the scope is slowly withdrawn and will do procedures (which may include biopsy or polypectomy) as required depending on what we find.

Most common reasons to recommend sigmoidoscopy:

  • Blood in stools or bleeding per rectum in young patients which is persistent and who are low-risk for cancer
  • Abnormal imaging study of left colon (to do 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

Things to do before scopy:

  • Fasting overnight
  • Avoid high fiber diet for three days before the scope
  • Enema will be given on arrival at the endoscopy center (to clear the stools)
  • Please inform us prior about any special medical conditions that the patient has (like diabetes, hypertension, heart valves, blood thinner medications, etc.), since that will require more special instructions.

Road to recovery after scopy:

  • Immediately after the scopy, we will observe the patient in the recovery room and monitor closely
  • Patients can resume normal diet after recovery
  • Patients may feel some cramping or bloatedness, which will resolve quickly once they start passing gas
  • If certain procedures were done during the scope, then certain medications has to be held off temporarily – which we will clearly instruct at discharge
  • If biopsy or polypectomy was done, then the histology of the same will have to be traced at the next clinic visit
  • 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.
  • Whereas if the procedure is done under local anesthesia, then the patient can go home alone on their own.

Possible complications:

  • Abdominal cramps
  • Bleeding, especially when polypectomy or biopsy is done
  • Perforation of colon
    • The incidence of the above two complications is very low when compared to the colonoscopy – about one in 1500 to one in 2000 and if it happens, then the patient may require emergency surgery and can be catastrophic
    • However the sigmoidoscopy procedure is overall safe in experienced hands

Incomplete scopy:

  • 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
  • In such patients, we may have to arrange for alternative imaging techniques like the CT Colonography or can repeat the scope at another day.


  • We will provide pictures of the lining of the colon taken during the scopy
  • We will provide histology report at the next clinic visit and explain/ proceed with further management
  • Depending on the findings, we will advise follow-up scopes in specified intervals
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