Various innovative roles for 3‐Fr microcatheters in pancreaticobiliary endoscopy

With the development of newer devices and technical innovations, pancreaticobiliary endoscopy is expanding to assume more advanced therapeutic roles. As with other devices, slimmed‐down “3‐Fr microcatheters” are considered to be opening new windows toward entirely new therapeutic techniques for various purposes. Our practical experience with a total of 34 consecutive patients in whom 3‐Fr microcatheters were applied during pancreaticobiliary endoscopic procedures clarified the potential roles of this instrument in pancreaticobiliary endoscopy. The major benefits of 3‐Fr microcatheters involve their slimness and flexibility. Applications of 3‐Fr microcatheters could be categorized into three groups according to the characteristics of usage: (1) utilization as a cannulation catheter for peroral digital cholangioscopy (n = 15); (2) selective advancement through deep flexures or severely stenotic ducts (n = 11); or (3) two‐devices‐in‐one‐channel technique (n = 8). The microcatheter worked successfully for cannulation of cholangioscopy in all but one case (14/15, 93.3%). For selective advancement, the microcatheter worked for troubleshooting in 9 of 11 cases (81.8%). With the two‐devices‐in‐one‐channel technique, the microcatheter proved satisfactory in all cases (8/8, 100%). In total, the microcatheter was successfully maneuvered in 31 of 34 cases (91.1%), following the failure of procedures using conventional endoscopic techniques. In terms of adverse events, cystic duct injury was only observed in two cases (5.8%), who recovered under conservative observation, because its slimness could minimize the damage. We believe that 3‐Fr microcatheters offer effective and safe salvage troubleshooting during various endoscopic pancreaticobiliary procedures that face troublesome situations with conventional strategies.