A Comparison of Two Colonoscopic Withdrawal Techniques on Colonic Polyp Detection: an Open, Randomised, Cross Over Trial

The identification and removal of polyps has been shown to prevent bowel cancer. Although colonoscopy is the best technique to identify polyps, polyps can be missed even in expert hands. Inspection of the bowel occurs predominantly during colonoscope withdrawal. Tailoring a patients position according to the segment of bowel being examined (dynamic position change) is a technique that has been shown to improve visualisation of the bowel wall and polyp detection. However, changing patient position during colonoscope withdrawal has not been widely accepted in clinical practice. This may be because of a lack of awareness of the literature, a perception that the benefit is negligible and the inconvenience of changing a patients position in addition to the small number of publications demonstrating this to be beneficial. We plan to compare the detection of polyps when colonoscope withdrawal is done with dynamic position change (a planned series of position changes to optimise mucosal visualisation) and the supine position (laid on back). These strategies will be compared by performing a double colonoscope withdrawal; The first withdrawal will be performed either supine or in the dynamic position. This will be followed by a second insertion and withdrawal in the alternative position. The order in which these strategies are performed will be randomised i.e. supine then dynamic or dynamic then supine.