Comparison of cap-assisted endoscopy vs. side-viewing endoscopy for examination of the major duodenal papilla: a randomized, controlled, noninferiority crossover study

Background  Use of a side-viewing endoscope is currently mandatory to examine the major duodenal papilla; however, previous studies have used cap- assisted endoscopyfor complete examination of the papilla. The aim of this study was to compare cap- assisted endoscopywith side-viewing endoscopyfor examination of the major duodenal papilla. Methods  This was a prospective, randomized, blinded, controlled, noninferiority crossover study. Patients were randomized to undergo either side-viewing endoscopyfollowed by cap- assisted endoscopyor cap- assisted endoscopyfollowed by side-viewing endoscope. Photographs of the major duodenal papillawere digitally editedto mask the cap area before they were evaluated by three blinded external examiners. Our primary end point was complete visualization of the major duodenal papilla. Secondary end points were the ability to examine the mucosal pattern, the overview of the periampullary region, overall satisfaction, and time to locate the papilla. Results  62 patients completed the study. Complete visualization of the major duodenal papillawas achieved in 60 examinations by side-viewing endoscopyand in 59 by cap- assisted endoscopy(97 % vs. 95 %). The difference between the two examinations was 1.6 % with a two-sided 95 % confidence interval of −4.0 % to 7.3 %, which did not exceed the noninferiority margin of 8 %. Cap- assisted endoscopyachieved better scores regarding the examination of mucosal pattern and overall satisfaction, whereas side-viewing endoscopyhad a better overview score ( P P  = 0.004, and P Conclusion  Cap- assisted endoscopyand side-viewing endoscopyhad similar success rates for complete visualization of the major duodenal papilla. Cap- assisted endoscopyis superior to side-viewing endoscopyregarding the mucosal pattern and overall satisfaction. Side-viewing endoscopygives a better overview of the periampullary region.