Flexible sigmoidoscopy is similar to a colonoscopy, except a shorter flexible tube, called a sigmoidoscope, is used to look inside the lower part of the colon (large intestine) and rectum only.
As with colonoscopies, images captured by the sigmoidoscope are relayed simultaneously onto a screen, and the procedure can be useful for investigating symptoms such as persistent diarrhoea or constipation, abdominal pain and rectal bleeding or blood in the stools. Flexible sigmoidoscopies are also routinely used in bowel cancer screening, which is recommended for adults aged 60-plus.
As with a colonoscopy, you’ll be asked not to eat anything for a certain number of hours beforehand and may be given medication (or an enema if necessary) to help clear the bowels, in order to maximise the effectiveness of the procedure. You’ll be asked to change into a gown and lie on your side while the procedure takes place. It shouldn’t be painful but might feel slightly uncomfortable. Some air will be gently pumped into your bowels, to enable the specialist to get a clearer look (this will pass naturally during the following 24 hours or so) and you’ll be able to go home shortly afterwards.
Sometimes, additional procedures and treatments can be carried out at the same time, such as removing tissue samples for lab testing (biopsies) and removing polyps (growths on the bowel walls) if they are detected.