Colonoscopy is a procedure where a long flexible scope is passed through the anus into the colon to visualize the inner lining of the colon. The colon or large intestine is approximately five feet long and is shaped like an inverted “U”. The flexible scope goes through the entire colon, going through bends and turns. 95% of the time, the entire colon is successfully visualized. In 5% of the time, because of anatomic considerations such as a very tortuous colon or the presence of an obstruction in the colon, complete visualization of the colon is not possible. In those cases, an x-ray will be needed to look at the rest of the colon.

In order to visualize the colon, it is necessary to clean the bowel out properly. Therefore, a bowel preparation is performed the day before the procedure. In addition, because the procedure can be uncomfortable, some form of sedation is given during the test.

A colonoscopy allows us to diagnose problems inside the colon that include infection, inflammation, the presence of tumors like polyps (often times benign), malignancy (cancer), the presence of inflammatory bowel disease (Crohn’s disease or ulcerative colitis), or the presence of diverticuloses (abnormal pouches in the colon). Biopsies of the bowel wall are done to diagnose many of these conditions and most small polyps can be safely removed colonoscopically using an electrical snare.

A colonoscopy is usually done to make a diagnosis of a patient complaint. In addition, the American Cancer Society recommends that everyone who reaches the age of 50 should undergo some kind of colon surveillance and the best way to get this colon surveillance is by colonoscopy. This recommendation is based on the fact that the majority of colon cancers will start off as benign polyps. Polyps will grow gradually and they can become malignant after five to ten years of growth. Polyps usually cause no symptoms. Should a polyp be found during the course of colonoscopy, they are removed using electrocautery either by direct burning or by snaring. The polyp is then sent for pathologic testing. Removing a benign polyp is normally curative, but the colon continues to be at risk for forming polyps in the future. Therefore, if a person is found to have polyps, the colonoscopy needs to be repeated within a year to five years, depending on the number of polyps, the size of the polyps and the pathology of the polyps.

There are other individuals who are at high risk for developing colon cancer and, therefore, need to have a colonoscopy at an earlier age or at more frequent intervals. These include people who have had a previous history of colon cancer or polyps, a history of ulcerative colitis, patients who have a hereditary form of polyps called familial adenomatous polyposis and those with first degree relatives who have had colon cancer. People who have a first degree relative with colon cancer need to be colonoscoped at age 40 or at the age ten years earlier than the age of the first degree relative who had colon cancer, whichever comes first. A colonoscopy is a very safe procedure with a low complication rate. There is a less than 1% chance of perforation or bleeding following a colonoscopy.

Should a polyp be too large to be removed colonoscopically, then that portion of the colon bearing the large polyp needs to be removed surgically. To aid the surgeon in locating the polyp at the time of surgery, the portion of colon bearing the polyp is tattooed during the time of colonoscopy. The surgery can be performed laparoscopically often times, leading to less pain, smaller incisions, and a quicker recovery.