Efficacy of Oblique Transparent CAP with Colonoscope for Trainees Analyzed with Magnetic Endoscope Imaging (MEI): A Preliminary Report

Abstract

Background: The oblique transparent cap (OTC, Top, Tokyo, Japan) attached to the tip of the colonoscope allows for good visualization and makes the procedure easier by maintaining the distance between the lens and the lumen. The aim of this study is to evaluate the efficacy of OTC with the colonoscope in trainees during the insertion of the colonoscope into the cecum with magnetic endoscope imaging (MEI). Methods: Consecutive routine colonoscopies were randomly assigned to be carried out either with or without the OTC. All procedures were performed by two trainees who had performed more than 150 cases and who were not allowed to view the imager view. Real-time views were recorded by the MEI throughout the procedure. Patients with colonic resections, poor bowel preparation and severe stricture in the colon were excluded. The instrument was a video colonoscope with an in-built magnetic imaging (CF260DI, Olympus Optical Co., Ltd., Tokyo, Japan). The degree of pain during insertion of the colonoscope into the cecum was assessed using the visual analog scale (VAS 0=not at all, 100=very severe). Between OTC-attached group and non-OTC attached group, the rate of completion, cecal intubation time and pain during insertion of the colonoscope into the cecum were recorded with MEI and the degree of pain in each type of loop and frequency of loop formation in the sigmoid colon were retrospectively analyzed. Result: Endoscopists performed 221 patients, and 110 patients were randomly allocated to OTC-attached group and 111 patients to non OTC-attached group. The rate of cecal intubation was similar between OTC-attached group and non-OTC attached group (100/110 vs.102/111, p=0.8153). Cecal intubation time was significantly shorter in colonoscope with the OTC (751seconds vs. 948seconds, p=0.001). There was no significant difference in degree of pain between OTC-attached group and non-OTC attached group (37.7 mm vs. 43.3 mm; p=0.136). Loop formations occur in 80.1% (177/221). N loop occurred in 47.1% (104/221), alpha loop in 22.2% (49/221) and reverse alpha loop in 10.8% (24/221). The degree of pain was significantly higher in reverse alpha loop (64.8 mm; p<0.001), N loop (44.2 mm; p<0.001), alpha loop (44.5 mm; p<0.001) than in non loop (14.2 mm) and the loops in the sigmoid colon (N, alpha, reverse alpha loop) tended to occur less in OTC-attached group but there was no significant difference. (83/110 vs. 94/111, respectively; p=0.094). Conclusions: Attaching the OTC to the tip of the colonoscope allowed trainees to decrease cecal intubation time and loops in the sigmoid colon tended to occur less compared with conventional colonoscopies.