Water immersion colonoscopy facilitates straight passage of the colonoscope through the sigmoid colon without loop formation: Randomized controlled trial

Background and Aim One of the major causes of pain during colonoscopy is looping of the instrument during insertion through the sigmoid colon, which causes discomfort by stretching the mesentery. There are many studies in colonoscope techniques, but they have not been assessed objectively with respect to colonoscope passage through the sigmoid colon without loop formation. The aim of the present study was to determine whether cap‐fitted colonoscopy and water immersion increase the success rate of insertion through the sigmoid without loop formation. Methods A total of 1005 patients were randomized to standard colonoscopy, cap‐fitted colonoscopy or water immersion technique. All examinations were carried out under a magnetic endoscope imaging device. Main outcome was the success rate of insertion without loop formation. Results Success rate of insertion without loop formation was 37.5%, 40.0%, and 53.8% in the standard, cap, and water groups, respectively (standard vs water P = 0.00014, cap vs water P = 0.00186). There were no significant differences among the groups regarding cecal intubation rate, cecal intubation time and number of polyps ≥5 mm per patient. Conclusions Water immersion increases the success rate of insertion through the sigmoid colon without loop formation. This practical technique, requiring only preparation of a cap and water, is useful without compromising cecal intubation rate, cecal intubation time, or polyp detection rate.