Colonoscopy

A colonoscopy is a specialised examination that allows our Singapore colorectal surgeon to visualise the large intestine (colon). By inserting a long and flexible tube with a HD video camera attached to one end known as a colonoscope, our doctor is able to guide the camera safely to the areas to be examined and detect any growths.

This screening test is usually recommended for evaluation of symptoms of the colon such as bleeding, change in bowel patterns, abdominal discomfort, or for colorectal cancer screening. The large intestine is the site where numerous disorders occur, such as haemorrhoids (piles), inflammation, polyps and cancer. If needed, treatment can also be performed at the same examination; for example, a polyp can be painlessly removed via the colonoscope using electrocautery (electrical heat).

The evening before a colonoscopy, you will need to take laxatives to clean out your large intestine. The procedure is done with you lying on one of your sides. An injection of a sedative and painkiller is usually given to make you relax and go into light sleep, and your pulse and oxygen level will be monitored with a finger-probe throughout the procedure.

Lubricant will be applied into your anus. A fingertip examination of the anal canal is first carried out. The colonoscope is then gently introduced into the anus and steered through the entire large intestine. The entire procedure takes between 15 to 20 minutes. In cases where a polyp removal is necessary, it may take 10 to 15 minutes longer, depending on the number of polyps to be removed.

Although colonoscopy is a relatively safe procedure, complications can sometimes occur. The 2 main risks are bleeding and bowel perforations with an occurrence of less than 1 in 1000 cases (0.1%). The risk is increased with procedures that require polyp removal because it creates a small ulcer that can sometimes bleed and the thinned-out area of polyp removal can lead to a perforation. Heavy bleeding after removal of a polyp sometimes requires transfusion or reinsertion of the colonoscope to control the bleeding.

After the procedure, you will be brought to the recovery area for monitoring and observation. You should not drive or operate machinery on the same day. For this reason, someone else should preferably be available to accompany you home. An appointment will be scheduled to review the findings of the colonoscopy, answer any questions you may have and, if needed, discuss future treatment.

Alternative tests to colonoscopy include barium enema and CT colonography. Both are specialised forms of x-ray tests that outline the colon and allow a diagnosis to be made. Study of the stools and blood can also provide some indirect information about the condition of your colon.

These exams, however, do not allow direct visualisation of the colon, removal of polyps, or tissue samples of abnormal findings. In addition, x-rays require exposure to radiation which is undesirable in children and young women of child-bearing age. For these reasons, colonoscopy is still the preferred gold standard for colonic examination.