Mechanisms of hyoscine butylbromide to improve adenoma detection: A case-control study of surface visualization at simulated colonoscope withdrawal Authors

In recent years, emphasis has been placed on colonoscopic quality, leading to reinvestigation of basic elements of colonoscopic extubation technique, such as withdrawal time, changing patient position, operator technique, and bowel preparation [1–4], that have been shown to impact polyp and adenoma detection rates. Basic technique can be improved to maximize adenoma detection with minimal additional financial cost. Routine use of antispasmodics during colonoscopy is controversial. Although the literature is inconsistent, in some studies, hyoscine butylbromide has been shown to accelerate colonoscopic intubation, and it may reduce patient procedural discomfort [5–7]. Other antispasmodics that have been investigated include glucagon, dicyclomine, hyoscyamine, atropine, peppermint oil, and warm water [8–14]. None of these has been shown to reduce intubation time, and only topical peppermint oil andwarmwater have been shown to reduce spasm scores or pain [9,14]. Until recently, very little investigation has been done of use of antispasmodics during the extubation or withdrawal phase of colonoscopy; however, the rationale for use of antispasmodics during extubation is not unreasonable. By reducing smooth muscle tone, haustral folds can be flattened, allowing better visualization of blind spots behind them, and peristaltic waves may be reduced, giving a still colonic surface onwhich to detect lesions. Indeed, studies using unblinding at CT colonography (CTC) suggest that most polyps missed by optical colonoscopy are on the back of folds in these blind spots [15]. A recent meta-analysis reported a relative risk for adenoma detection of 1.09 (95% confidence interval 0.91–1.31) and for polyps of 1.13 (95% CI 0.92–1.38), numerically but non-significantly, in favor of hyoscine [16], and in a very large cohort study (n=31088), the proportion of patients with at least one adenoma detected was 50.1% with hyoscine versus 44.5% without (relative increase 12.6%, P<0.001) with