Novel ex-vivo training model for free-hand insertion using a double-bending peroral direct cholangioscope

Background and Aim Several experts of direct peroral videocholangioscopy (D-PVCS) using a conventional ultraslim endoscope have reported its usefulness for the diagnosis and therapy of biliary tract diseases. We have additionally developed a dedicated double-bending D-PVCS (DBD-PVCS) technique for free-hand scope insertion. In this study, we developed an ex-vivo training model for the free-hand DBD-PVCS technique and compared it with the technique using a conventional ultraslim endoscope. Methods The ex-vivo model was made for training using a U-shape insertion pattern. A 3rd prototype endoscope and an ultraslim upper GI endoscope were used. Two experts and 9 non-experts performed D-PVCS using the free-hand technique. Results The 2 experts could not advance the tip of the endoscope to the hilar portion using the free-hand technique, but they could achieve technical successful insertion to the hilar portion with the 3rd prototype cholangioscope using the free-hand technique alone. The non-experts could not advance the tip of the endoscope to the bile duct using the free-hand technique. On the other hand, 2 (22.2%) non-experts could advance the tip of the 3rd prototype cholangioscope using the free-hand technique before the training conducted by the experts. After the training, all the non-experts could advance the tip of the 3rd prototype cholangioscope to the hilar portion. Conclusions The novel ex-vivo model using a 3rd prototype cholangioscope was useful for training in the use of the free-hand D-PVCS technique.