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Background/Aims: Using an appropriate guidewire can increase the success rate of selective cannulation in endoscopic retrograde cholangiopancreatography. The purpose of this technical study was to investigate the characteristics of each guidewire type and to evaluate its efficiency and rapidity of insertion. Methods: We conducted a three-point bending test using a universal testing machine to investigate the flexibility and bending features of each guidewire. 3D-printed silicone tubes with various types of stricture and a hand-made biliary tree silicone model with sixstranded intrahepatic ducts were used to evaluate the success rate and insertion time of each guidewire. Results: In the three-point bending test, the characteristics of each guidewire were classified. We found that the bending strengths and times were independent of shaft thickness. Using two in vitro biliary duct models, we determined that the success rate and total insertion time were better for guidewires with a resilient shaft and angled tip than for other types of guidewires (p<0.001). Although thickness of the guidewire affected the success rate (p<0.05), it did not affect the total insertion time (p≥0.05). Conclusions: Among several types of guidewire, some factors (resilient shaft, highly flexible, and angled tip) appeared to be associated with the efficiency and rapidity of the guidewire insertion. [ABSTRACT FROM AUTHOR]

Background/Aims: The efforts to improve biliary plastic stents (PSs) for decreasing biofilm formation and overcome short patency time have been continued. The aim of this study is to evaluate the effect of advanced hydrophilic coating for patency and biodurability of PS. Methods: Using an in vitro bile flow phantom model, we compared patency between prototype PS with hydrophilic coating (PS+HC) and prototype PS without hydrophilic coating (PS-HC). We performed an analysis of the degree of luminal narrowing by microscopic examination. Using an in vivo swine bile duct dilation model made by endoscopic papillary closure and stent insertion, we evaluated biodurability of hydrophilic coating. Results: In the phantom model, PS+HC showed less biofilm formation and luminal narrowing than PS-HC at 8 weeks (p<0.05). A total of 31 stents were inserted into the dilated bile duct of seven swine models, and 24 stents were successfully retrieved 8 weeks later. There was no statistical difference of stent patency between the polyethylene PS+HC and the polyurethane PS+HC. The biodurability of hydrophilic coating was sustained up to 8 weeks, when assessing the coating layer by scanning electron microscopy examination. Conclusions: Advanced hydrophilic coating technology may extend the patency of PS compared to uncoated PS. [ABSTRACT FROM AUTHOR]