Sigmoidoscopy is a diagnostic procedure performed with lighted viewing tubes called scopes introduced through the anus to inspect the lower end of the large intestine (sigmoid colon). The procedure uses a particular scope which permits the doctor to inspect for any signs of disease or abnormalities such as tumours, polyps, ulcers, haemorrhoids, inflammation or bleeding.
Sigmoidoscopy is usually performed to investigate unexplained or persistent bleeding, diarrhoea or constipation. It may be also performed to screen for colon cancer or to monitor existing abnormalities or assess treatment.
Before performing the procedure, your bowels are evacuated with the help of an enema or laxative to provide a clear unobstructed view. The procedures may be performed under mild sedation while lying on your left side or kneeling down. You may experience some discomfort or an urge to pass stool or gas with the procedures. During a sigmoidoscopy, a long lighted tube called a sigmoidoscope is carefully guided to the sigmoid colon. The lens and light system of the sigmoidoscope allows it to be flexible and provides your doctor with a clear view even around bends in the intestine. To further improve visibility, the intestine may be suctioned or filled with air. Tissue samples may be obtained (biopsy) or small growths removed with the help of tiny instruments passed through the scope. A local anaesthetic is usually administered when a biopsy is done. Sigmoidoscopy usually takes about 5-15 minutes.
As with any invasive procedure, sigmoidoscopy may be associated with certain complications such as pain, bleeding or infection, and perforation of the rectum or colon.