CHICAGO — Using a retrograde viewing device that looks behind haustral folds and flexures in the colon during colonoscopy was associated with the detection of significantly more polyps and adenomas than relying on a standard colonoscope alone, a prospective study has found.
Endoscopists who performed the procedures said that the Third Eye Retroscope found 11% more adenomas in the entire colon and 15% more in the right colon, where concerns are highest about missed lesions, Dr. Jerome D. Waye said at the annual Digestive Disease Week.
The scope, manufactured by Avantis Medical Systems, “provides a simultaneous backward and forward view of the colon,” said Dr. Waye of Mount Sinai Medical Center, New York. “The retroscope passes through the colonoscope channel and then automatically retroflexes 180 degrees. It carries its own light source and has a camera with a very wide angle lens. The camera looks backward while the colonoscope looks forward.”
Both images are simultaneously displayed on the video monitor, he said. When a lesion is detected, the retroscope has to be withdrawn so that the polyp can be snared; the scope is then reinserted and the procedure continues. Although this process can lengthen the overall time of the colonoscopy, the increased polyp yield is a worthy tradeoff, Dr. Waye said.
He presented the results of a prospective study of 249 patients who underwent screening or surveillance colonoscopy at any of eight U.S. sites.
The retroscope was used in conjunction with standard colonoscopy in all cases.
Whenever a polyp was identified, the endoscopist noted whether it was also seen on the colonoscope, or whether it appeared only on the retroscope.
Standard colonoscopy detected 257 polyps throughout the entire colon.
The retroscope detected 34 additional lesions that were not seen on the colonoscope, a significant 13% increase in yield.
The increase was even better when only the right colon was considered. Here, the colonoscope detected 133 lesions, while the retroscope identified an additional 22, a significant increase of 17%.
The average withdrawal time with the retroscope procedure was about 10 minutes, he said.
Standard colonoscopy detected 136 adenomas in the entire colon; the retroscope identified an additional 15, a significant 11% increase.
In the right colon, the standard scope identified 87 adenomas, and the retroscope identified an additional 13, a significant increase of 15%.
The average size of polyps detected by the retroscope was 4.6 mm, not significantly different from the average 4.2 mm size detected by the colonoscope.
The retroscope identified significantly larger adenomas than did the colonoscope (5.2 mm vs. 4.4 mm).
There were no technical failures during any of the procedures, he said.
Dr. Waye said he had no relevant financial disclosures and is not associated with Avantis Medical Systems.
The retroscope consists of a camera and light source on a flexible catheter.
Source Courtesy Dr. Douglas K. Rex and Avantis Medical Systems, Inc.
The screen splits to show both forward and backward views of the colon.
Source Courtesy Avantis Medical Systems, Inc.