As a result,

the needle deviated from the axis of the bile duct, causing perforation. In our subsequent cases, we strictly restricted the cutting wire extension to 3 mm beyond the catheter tip, and no additional perforation occurred. Potentially, such an adverse event can be avoided by bending back the needle tip by 180 degrees onto the catheter shaft and Cell Cycle inhibitor inserting the device over the guidewire, which may avoid inadvertent cutting at an angle or extending too much of the wire tip, although this technique has the potential of causing asymmetric dissection and perforation. Other adverse events in this series include post-ERCP pancreatitis, hyperamylasemia, and cholangitis. It is not clear whether needle-knife electrocautery is the risk factor for post-ERCP pancreatitis or cholangitis. The case of acute pancreatitis and the two cases Metformin purchase of hyperamylasemia may be because of the complexity and prolonged time of the ERCP procedure (the difficult biliary cannulation approach with transpancreatic sphincterotomy in one case as opposed

to chronic pancreatitis in another case) because the needle-knife was not used on or near the papilla in the three cases. Cholangitis may also arise from incomplete drainage of the biliary tree in a Bismuth type IV Klastkin tumor. All adverse events were mild and managed conservatively. No procedure-related deaths occurred. Malignant biliary strictures Amrubicin sometimes mimic a benign lesion and vice versa.35 and 36 Studies have shown that the length of stenosis is often longer in malignant strictures than in benign ones.37 and 38 The adverse event rate of wire-guided needle-knife incision for refractory biliary strictures may be higher in malignant biliary strictures because of the length of stricture is usually longer in malignant cases than in benign cases and therefore more time is needed to dissect it. The patient with self-limited bleeding in our series, however, was diagnosed with a benign hilar stricture

after orthotopic liver transplantation, and the length of the stricture was as long as 5 cm. This case implies that the risk of adverse events may relate to the length of the stricture rather than the nature of the stricture. The sample size in our study is small, and therefore further studies using more patients and in multiple centers are required to demonstrate the safety of this novel technique. In addition, further investigation is needed to identify risk factors and define the optimal indications of needle-knife electrocautery for the sake of reducing adverse events and improving the safety. In summary, wire-guided needle-knife dissection is a feasible alternative for refractory biliary and pancreatic strictures when conventional techniques fail to dilate the narrowing. In skilled hands, this novel technique has a high success rate in bridging stenoses with acceptable risks.