Published online Jan 14, 2015. doi: 10.3748/wjg.v21.i2.593
Peer-review started: April 24, 2014
First decision: August 6, 2014
Revised: August 21, 2014
Accepted: September 29, 2014
Article in press: September 29, 2014
Published online: January 14, 2015
AIM: To evaluate the new RetroView™ colonoscope and compare its ability to detect simulated polyps “hidden” behind colonic folds with that of a conventional colonoscope, utilizing anatomic colon models.
METHODS: Three anatomic colon models were prepared, with twelve simulated polyps “hidden” behind haustral folds and five placed in easily viewed locations in each model. Five blinded endoscopists examined two colon models in random order with the conventional or RetroView™ colonoscope, utilizing standard withdrawal technique. The third colon model was then examined with the RetroView™ colonoscope withdrawn initially in retroflexion and then in standard withdrawal. Polyp detection rates during standard and retroflexed withdrawal of the conventional and RetroView™ colonoscopes were determined. Polyp detection rates for combined standard and retroflexed withdrawal (combination withdrawal) with the RetroView™ colonoscope were also determined.
RESULTS: For hidden polyps, retroflexed withdrawal using the RetroView™ colonoscope detected more polyps than the conventional colonoscope in standard withdrawal (85% vs 12%, P = 0.0001). For hidden polyps, combination withdrawal with the RetroView™ colonoscope detected more polyps than the conventional colonoscope in standard withdrawal (93% vs 12%, P≤ 0.0001). The RetroView™ colonoscope in “combination withdrawal” was superior to other methods in detecting all (hidden + easily visible) polyps, with successful detection of 80 of 85 polyps (94%) compared to 28 (32%) polyps detected by the conventional colonoscope in standard withdrawal (P < 0.0001) and 67 (79%) polyps detected by the RetroView™ colonoscope in retroflexed withdrawal alone (P < 0.01). Continuous withdrawal of the colonoscope through the colon model while retroflexed was achieved by all endoscopists. In a post-test survey, four out of five colonoscopists reported that manipulation of the colonoscope was easy or very easy.
CONCLUSION: In simulated testing, the RetroView™ colonoscope increased detection of hidden polyps. Combining standard withdrawal with retroflexed withdrawal may become the new paradigm for “complete screening colonoscopy”.
Core tip: Polyps located on the proximal side of colon folds can be challenging to detect. The new RetroView™ colonoscope has a short turning radius that allows a retroflexed view of the colon during withdrawal. In this bench colon model study, the RetroView™ colonoscope detected more proximally-located, “hidden” polyps during retroflexed withdrawal, than a conventional colonoscope withdrawn in standard fashion. The highest polyp detection rate was achieved when the RetroView™ colonoscope was withdrawn in retroflexion followed by standard withdrawal. This combination of standard and retroflexed withdrawal holds promise for optimizing polyp detection in patients undergoing screening colonoscopy.