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‘Underwater’ colonoscopy: Easier for doctor, less pain for you

March 03, 2016 | William E. Karnes, MD
A scope moving through the colon in a colonoscopy

Good news: Your next colonoscopy may be a little more comfortable if it’s performed underwater.

No, you won’t be getting into a pool, but your colon will be — in a way.  

An “underwater” colonoscopy uses a gentle stream of water instead of puffs of air to help your doctor guide the scope through the many twists and turns of your colon.

Thanks to design advancements to our medical instruments, it’s now easier for gastroenterologists to learn and use this method, which may mean less pain and an easier recovery for you.

How ‘underwater’ colonoscopy works

Colonoscopies are the “gold standard” of colon cancer screening methods. The screenings allow gastroenterologists to see the entire large intestine through a scope — a flexible tube equipped with a light, video camera, channels for air and water, and instruments to remove any precancerous polyps they encounter.

When performing a traditional colonoscopy, the physician uses puffs of air to expand the colon to better see what’s there.

In an “underwater” colonoscopy, the physician uses water, which, instead of expanding the colon, weighs it down and makes it a little straighter, meaning there are fewer and less extreme angles to navigate. It basically opens up the large intestine for inspection.

As the scope is retracted, the water is removed.

I now use the “underwater” colonoscopy method for almost all my patients, though sometimes I use a combination of air and water, depending on which gives me the best view.

No matter which method is used, the colonoscopy prep and polyp removal process remains the same.

Less bloating, cramping and gas for you

Traditional colonoscopies can leave you full of air, making you uncomfortable and looking like a blimp until you, well, pass gas. No matter how much we try to remove the air, some of it escapes to the small bowel, meaning you may have ­some cramping, gas and bloating.

Also, because the colon expands in a traditional colonoscopy, there is more room for the scope to move back and forth and form loops, which also can result in cramping.

In “underwater” colonoscopies, the colon does not expand, nor is air left behind, which can make the procedure less painful and the recovery faster.

Colonoscopies are crucial in preventing and detecting colon cancer early.

Men and women should be screened every 10 years starting at age 50. We may recommend you start the screenings earlier or have them more often if you have a family history of colon cancer or personal history of precancerous polyps.

Don’t let the fear of a little discomfort — which the “underwater” method may lessen — keep you from getting this potentially life-saving procedure.

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