What is Sigmoidoscopy?

A sigmoidoscopy is a medical procedure which involves the use of a tool called a sigmoidoscope to look into the sigmoid colon, the lower part of the colon. This procedure is sometimes recommended for colon cancer screening, and it can also be used as a diagnostic tool to determine why a patient is experiencing diarrhea, rectal bleeding, and other symptoms related to the gastrointestinal tract. It is important to remember that a sigmoidoscopy is not the same thing as a full colonoscopy, which actually looks at the entire colon, and therefore it is possible to miss signs of colon cancer or disease with a sigmoidoscopy.

There are two basic types of sigmoidoscopy. In a flexible sigmoidoscopy, a physician uses a flexible probe which is gently inserted into the rectum and slowly extended into the sigmoid colon. In a rigid sigmoidoscopy, a rigid probe is used; because of the greater discomfort associated with this technique, most patients and physicians prefer flexible sigmoidoscopies. During the procedure, which lasts around 20 minutes, the physician will be able to see what's going on inside the part of the colon which leads to the large intestine.

Typically a patient who books a sigmoidoscopy must go on a liquid diet for 24 hours before the procedure, and he or she may be required to take a laxative as well. This clears the colon out, making it easier to visualize its internal structure with the sigmoidoscope, and it also tends to be make the procedure more comfortable and less messy. During the sigmoidoscopy, the patient lies on his or her left side, as this provides the most comfortable and workable angle. Sedatives are not usually prescribed unless a patient specifically requests them.

With the use of a camera and a light, the physician can see the inside of the colon as the sigmoidoscope is inserted. If an object of interest such as a lesion or polyp is identified, the physician can insert tools into the probe to collect a sample for the purpose of biopsy. In some cases, this may cause mild bleeding which requires cauterization; in extreme cases, the bleeding may need to be corrected surgically, but this is fairly rare. After the procedure is over, the doctor can discuss his or her findings and make recommendations, which are typically determined by whether or not a sample was taken for biopsy.

As with any medical procedure, there are some potential complications to sigmoidoscopy. These procedure is sometimes accompanied with extreme discomfort and rectal bleeding. In very rare cases, it is also possible to perforate the bowel with the probe, requiring immediate surgery to correct the problem. Make sure to discuss the pre and post procedure care requirements and potential risks of sigmoidoscopy with your doctor before you consent to the procedure.