Water-assisted colonoscopy: an international modified Delphi review on definitions and practice recommendations

Post written by Sauid Ishaq, FRCP, PhD, from Russell Hall, Dept. of Gastroenterology, and Birmingham City University, Birmingham, United Kingdom.

The focus of the study was to get consensus among experienced colonoscopists (experts and non-experts in WAC) on definitions and practice of water immersion (WI), water exchange (WE), and UWR.

Water-assisted colonoscopy (WAC) and underwater polyp resection (UWR), being hailed as innovative approaches, are poorly understood, thus impeding practice diffusion among non-practioners of WAC. The goal of our International Delphi review was to critically assess and grade research evidence with clinical implications of WAC and UWR. Evidence-based statements were formulated and provided to experts and non-experts on WAC and UWR. Voting was conducted anonymously in the second and third round, with 80% agreement defined as consensus.

Consensus was achieved on 11 statements, but the 3 most important ones were:

 1.      Water exchange (WE) and water immersion (WI) colonoscopy techniques are not the same in implementation and outcomes.

2.      WE is superior to WI and conventional colonoscopy in significantly reducing pain and increasing the adenoma detection rate (ADR).

3.      Underwater mucosal resection without submucosal lifting of large and small colorectal sessile and flat lesions is feasible based on available data and can achieve better outcomes than conventional resection.

Our Delphi review was strengthened by addressing early concern regarding definitions and application of WAC, which will improve understanding of WAC techniques and practice recommendation.

We concluded that WI and WE are not the same in implementation and outcomes. UWR of colorectal lesions is a safe alternative to conventional techniques.

We very much hope that the results of this modified Delphi will allow colonoscopists to correctly apply WI and WE techniques depending on the outcome they want to achieve, tailoring the procedure to the patient to optimize safety, comfort, and efficiency. In addition, an accepted definition for WI and WE agreed on by a group of experienced colonoscopists will be valuable for designing future studies on WAC.


Figure 1. Modified Delphi flowchart. IWATERS, International Water-Aided Techniques in Endoscopy (Education) and Research Society.


Read the full article online.

The information presented in Endoscopedia reflects the opinions of the authors and does not represent the position of the American Society for Gastrointestinal Endoscopy (ASGE). ASGE expressly disclaims any warranties or guarantees, expressed or implied, and is not liable for damages of any kind in connection with the material, information, or procedures set forth.

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