Digestion Q&A by Dr. Lee

Answer:

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The objective of a colonoscopy is to examine the entire colon (from rectum to cecum. (The cecum is the part of the colon where the small intestine joins the colon. It also is the area of origin of the appendix.) More than 90% of the time, an endoscopist can reach the cecum with a colonoscope safely. The reasons for not being able to reach the cecum with a colonoscope include:

1. The colon is very long.
2. The colon is very curvy and redundant.
3. Pelvic adhesions due to prior surgery or intra-abdominal inflammation (for example, diverticulitis) make the colonoscopy difficult.
4. There is excessive patient discomfort.
5. Patients develop abnormal medical conditions (heart rhythm, blood pressure, breathing) that make the endoscopist want to terminate the procedure before reaching the cecum for reasons of patient safety.

If the doctor cannot reach the cecum, he/she may order a barium enema to help visualize the unexamined part of the colon. An alternative to barium enema is computerized tomographic (CT) colonography.

Thank you for your question.