Doctors using a new optical device mounted on the end of their scopes, found significantly more polyps in the colon during routine colonoscopies. Called the Third Eye Retroscope™, it lets gastroenterologists see both forward and backward as the scope moves through the colon.
Although colonoscopy is extremely sensitive and will discover most colon polyps during an exam, some are missed. They may be hidden in the back side of folds in the colon wall or not seen because they are outside of the half circle view of the standard colonoscope. The wider view allowed doctors to find 13 percent more polyps and 10 percent more adenomatous polyps, the ones more likely to become cancer.
In a study of 214 patients, the Third Eye found 27 polyps and 13 adenomatous polyps that were missed with conventional colonoscopy. More than ten percent of patients had at least one additional polyp uncovered with Third Eye, and seven patients (three percent) would have been dismissed with a clean colonoscopy had not the new technology found missed polyps.
The retroscope looks a little like a buttonhook. Attached to the end of the colonoscope, it sends video pictures back to a split screen so that the physician can see both the standard forward view and the additional backward look at the same time. It decreases the average overall area in the that cannot easily been seen from 31 square inches to less than 3.
Using the device takes a little more time, and if polyps are found it must be withdrawn so that instruments to remove them can use its space. While all the gastroenterologists involved in the study were highly experienced, they needed to learn to watch both views on the split screen.
Douglas Rex, M.D. reported on the use of the device at the American College of Gastroenterology Scientific Meeting in Orlando. Dr. Rex is professor at Indiana University School of Medicine and a gastroenterologist at the IU Cancer Center.
The Third Eye Retroscope™ is manufactured by Avantis Medical Systems, but for now is only available for clinical trial work. Approved by the FDA in 2007, a full commercial roll-out is planned for 2009.
Source: Rex D, et al ,The Third Eye retroscope improves detection of polyps during colonoscopy, Abstract 40, American College of Gastroenterology Scientific Meeting, October 7, 2008.