The Third Eye Retroscope Improves Detection of Polyps During Colonoscopy – a Prospective Efficacy Evaluation: 1326

Purpose: Colonoscopy is currently considered the “gold standard” for colorectal cancer screening. However, lesions may be missed, especially on the proximal aspect of haustral folds and flexures or behind the ileocecal valve. The Third Eye™ Retroscope™ (TER) provides a retrograde view that complements the forward view of a standard colonoscope. We present initial results based on the first 214 subjects enrolled in a prospective study to evaluate efficacy of the device for detecting polyps that are missed during colonoscopy. Methods: This multi-center study involves 14 experienced endoscopists at eight U.S. sites. Investigators have examined 214 patients (age 55–80) during screening or surveillance colonoscopy using a Third Eye Retroscope (Avantis Medical Systems, Inc., Sunnyvale, CA) in combination with a standard colonoscope (CF-Q160AL, CF-Q180AL or CF-H180AL – Olympus America Inc.). After cecal intubation, the disposable TER is inserted through the instrument channel of the colonoscope. As it emerges from the channel, the distal tip of the device turns 180° to provide a retrograde view. During withdrawal, the two video images are observed side-by-side on a wide-screen monitor. For each polyp, the endoscopist indicates whether it is visible through the colonoscope or is detected with the colonoscope only because it was first detected with the TER. Results: In these initial 214 subjects, 203 polyps were identified with the standard colonoscope. With the TER, 27 additional polyps were detected, a 13.3% increase (P < .0001). With the colonoscope, 105 adenomas were found, and with the TER, 13 more adenomas were detected, a 12.4% increase (P < .0001). Mean size of lesions detected with the TER was similar to mean size of lesions found with the colonoscope (see Table). In 21 individuals (9.8%), at least one additional polyp was found, and in 7 patients (3%), the polyp detected with the TER was the only one found. Every polyp that was initially detected with the TER was then located and removed with the colonoscope.Table: Additional Lesions Detected with the Third Eye Retroscope.Conclusion: Initial results of this prospective multi-center study indicate that a retrograde-viewing device revealed areas that are hidden from the forward-viewing colonoscope and allowed detection of 13.3% additional polyps, including 12.4% additional adenomas.Figure: A split-screen monitor displays the colonoscope's video image on the left and the Third Eye's image on the right. The Third Eye image reveals a 0.3 cm adenoma on the proximal aspect of a haustral fold.