What is sigmoidoscopy

A sigmoidoscopy is a procedure used to see inside the sigmoid colon and rectum. Sigmoidoscopy can detect inflamed tissue, abnormal growths, and ulcers. The procedure is used to look for early signs of cancer and can help doctors diagnose unexplained changes in bowel habits, abdominal pain, bleeding from the anus, and weight loss.

What are the sigmoid colon and rectum

The colon comprises three main parts: the ascending colon, the transverse colon, and the sigmoid colon—often called the descending colon. The colon absorbs nutrients and water and forms stool.

The sigmoid colon is the last one-third of the colon. The rectum is about 15.2cm long and connects the sigmoid colon to the anus. Stool leaves the body through the anus. Muscles and nerves in the rectum and anus control bowel movements.

How is flexible sigmoidoscopy different from colonoscopy

Only the sigmoid colon can be seen during this procedure, whereas colonoscopy allows the doctor to see the entire colon. Colonoscopy is the preferred screening method for cancers of the colon and rectum.

Before the procedure

At the Day Hospital about 2 hours before the procedure, one or more enemas are administered rectally to remove all solids from the sigmoid colon. The enema produces a watery evacuation of the bowel and provides a cleansing action inducing complete emptying of the sigmoid colon usually within 2 to 5 minutes.

Examination of the Sigmoid Colon

A long, flexible, lighted instrument called a sigmoidoscope, or scope, is inserted into the anus and slowly guides it through the rectum and into the sigmoid colon. The scope inflates the colon with air to give the doctor a better view. A small camera mounted on the scope transmits a video image from inside the colon to a computer screen, allowing the doctor to carefully examine the tissues lining the sigmoid colon and rectum. When the scope reaches the transverse colon, the scope is slowly withdrawn while the lining of the colon is carefully examined again.

Risks associated with Sigmoidoscopy

Cramping or bloating may occur during the first hour after the procedure. Bleeding and puncture of the large intestine are possible but uncommon complications. Patients who develop any of these rare side effects should contact their doctor immediately:

  • severe abdominal pain
  • fever
  • bloody bowel movements
  • dizziness
  • weakness

If you wish to have full details of rare complications, or if you have any reservations or wish to discuss the matter further please inform the nursing staff before your procedure.