Underwater Colonoscopy



How can we reduce pain and distension during an underwater colonoscopy versus a standard colonoscopy ?

To overcome pain and abdominal distension a few world experts came up with an idea to replace air with small amount of water to perform what is known as “water assisted or water aided colonoscopy” (WAC).

How underwater colonoscopy is different.

Water-assisted or water-aided colonoscopy” comprises different techniques that entail infusion of water ( Picture 1 below) in lieu of gas insufflation to allow instrument insertion to the cecum ( Picture 2). Scope withdrawal is carried out with air or CO2 insufflation to distend the lumen for exploration, as usually done in conventional colonoscopy also.

Standard water-aided exchange entails gasless insertion of scope to the caecum with the gas insufflation turned off. Water is infused and near-simultaneously sucked to maximize cleanliness without distending the lumen of colon. This technique has many advantages proven in well-designed clinical studies, such as: 

1- The colon is less distended and does not stretches or elongates, this prevents  the formation of loops and bends as we see in conventional colonoscopy with gas, hence insertion is easy and pain free. In addition, warm water does have some potential antispasmodic properties.

2- Water exchange allows maximum cleaning that in turn allows better visualization of the colon, with increased diagnostic yield also due to less washing and related distractions for the endoscopist during the search for polyps. It is proven by clinical studies that underwater colonoscopy detects more pre-cancerous lesions than conventional colonoscopy.

3- The majority of the patients does not require sedatives and can be potentially discharged immediately after the procedure. 

4- The patient’s willingness to undergo a repeat colonoscopy was used as an outcome by some studies. This outcome was higher with water-aided colonoscopy than with conventional colonoscopy.

What equipment is required for a  underwater colonoscopy.

The same standard colonoscope is used. A pump with a foot peddle is attached, that allows the endoscopist to infuse water. Water is sucked back through scope suction channel.

How much water is used in underwater colonoscopy

Usually 600ml to a litre. But water is infused and sucked at the same time to prevent distension of colon and soiling of the patient.

How polyps / pre-cancerous lesions removed underwater 

Polyps/ pre-cancerous lesions are mushroom-like growth in the lining of the colon.

Endoscopist use electrified wire loop, that is passed through the colonoscope over the polyp, once closed this wire loop act as noose. Once polyp is grasped, electrical current is passed to perform a polypectomy (figure 3). This procedure is usually painless.

Is underwater colonoscopy more expensive?

In a matter of fact, it cost less, as no sedation related cost and no need to use recovery bed. In addition, patient can resume normal activity quicker.

Is underwater colonoscopy available every where

Currently Professor Sauid Ishaq is the only Gastroenterologist who performs  this novel technique  for patients referred for a colonoscopy. It is a cutting edge treatment only available at a few centres worldwide, including US, Italy, Spain, China and Japan. Professor Ishaq leads an international group. Underwater colonoscopy has been introduced in UK since 2014. and the Interest is growing rapidly and patients love it. 

We have published teaching videos and performed live demonstrations in international and National meetings. 

In the UK we hope this will generate nationwide interest among endoscopists to take up this new technique. We plan to set up hands on workshops to train more endoscopists worldwide.

Underwater Colonoscopy