New Colonoscopic Technology or Back-to-Basic Techniques?

Abstract

TO THE EDITOR: We thank Dr. Matsushita and colleagues for their interest in our article that showed that in computerized tomography (CT) simulation of optical colonoscopy use of a wide angle (170°) colonoscope increased absolute surface visualization by approximately 5%, and that simulated addition of retrograde viewing auxiliary imaging device (RVAID) led to almost total surface visualization. Matsushita et al. have concerns about the simulation of retrograde view as they feel that pan-colonic retrograde examination is not feasible in routine clinical settings. We agree with these concerns when using standard or even short bending section instruments. In trials attempting additional retroflexed examination, only the proximal colon was examined because of the real risk of impaction in the more angulated, narrower left colon (1). However, the RVAID that we simulated (Third Eye Retroscope, Avantis Medical, CA) is a catheter-mounted videochip that exits the colonoscope via the biopsy channel for a few inches (2). Unlike a retroflexed colonoscope, the catheter is preshaped to retroflex in a very tight radius (approximately half an inch), making impaction unlikely. The first human trials of this device in 12 patients have recently been reported and appear to confirm this, with safe and successful navigation around flexures and in both the left and right colon (2). It remains to be seen whether the addition of RVAIDs to standard colonoscopes translates into increased adenoma detection in clinical practice.