Definition The sigmoid is the last small stretch of colon, or large intestine, before the rectum. A sigmoidoscopy is a procedure that is done to examine this part of the bowel as well as the rectum and the anus.
Who is a candidate for the procedure? This procedure may be done if a doctor suspects or knows a person has:
a twist in the lower bowel that is blocking the bowel or causing pain
This procedure is also done to screen for bowel cancer in healthy persons starting at age 50. It may be done before age 50 if a person has risk factors, such as a family history of bowel cancer.
How is the procedure performed? Before the procedure, the bowel must be cleaned out to allow a good view. If too much stool is in the lower colon, the doctor will be unable to see the inside walls of the bowel. A person will be asked to stop eating at least 8 hours before the procedure. Laxatives and an enema are often given before the procedure. This helps to clear the bowel. This preparation is very important. If the instructions are not followed, the procedure may have to be repeated.
The procedure takes about 15 to 20 minutes. It may be done in a clinic, a doctor's office, or the hospital. The person may be given a medication to help him or her relax. Before the procedure, the person changes into a hospital gown. He or she then lies on an examination table in a special position, such as:
on the left side with knees drawn up toward the chest
on the back with knees drawn up and the feet in stirrups
During the examination, a sigmoidoscopy is used to allow the doctor to see the inside of the bowel. Sigmoidoscopy uses a special tube with a light and sometimes a camera on to the end of it.
The anus is lubricated and the sigmoidoscope is passed through it into the rectum. This is somewhat uncomfortable and may cause an urge to defecate. Puffs of air through the tube are used to help open up the colon. This makes it much easier to get a good view of the tissues.
During the procedure, the doctor can also:
remove any colorectal polyps, tiny growths on the walls of the bowel
take a sample of tissue to be examined in a laboratory, known as a biopsy
straighten out a loop of twisted colon
What happens right after the procedure? Most people handle the procedure very well and have no problems. It can be uncomfortable, but it is not usually painful. However, after the procedure, a person may notice the following:
flatulence pains
slight rectal bleeding, if samples of tissue or polyps were removed
The person may need to be driven home after the procedure if sedation has been given. This is because the medications that are used to relax the person may affect the ability to drive.
The doctor will usually talk to the person right after the procedure about what he or she found. If samples of tissue or polyps were removed, it may take several days for the results to come back. These results will be discussed at a follow-up visit.
What happens later at home? A person should call the doctor if there are any signs of problems after the procedure, such as:
What are the potential complications after the procedure? This procedure rarely causes problems. However, there is a small risk of bleeding or infection. In rare cases, a small hole may be made in the bowel. This may need to be treated with antibiotics or sometimes surgery. An allergic reaction to medications given for relaxation may also rarely occur.
Author: Francesca Coltrera, BA Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
