Cannulation success with standard techniques reported to be around 95% even in expert hands and despite all efforts, it can be challenging that needs an alternate intervention.~NKF is recommended as the initial technique for pre-cutting because the rate of post-ERCP pancreatitis (PEP) is significantly low but there is an ongoing debate about limiting its use in certain types of papillae with a long intra-mural segment~Indeed the shape of the papillae influences the success of bile duct cannulation and the choice of the pre-cutting technique. Type-2 and Type-3 papillae are more difficult to cannulate than Type-1. NKF can be performed as the initial technique for pre-cutting in protruded Type-2 and Type-3 papillae but it has some limitations.~First of all, the incision can be erratic because it is performed without a guidewire and uncontrolled. This can cause a tattered mucosa as the incision progress and the papillae lose anatomic contours. Some amount of bleeding may also unavoidably occur and the field of view further impaired. If the initial incision line is incorrect and additional incision is needed, more crumpled and deformed papillae with irregular margins may be encountered. These undesired results are frequently experienced and prevent a clean-cut, thus further complicate the cannulation. Even perforation can occur.~Recently the investigators described a novel technique, PA-EMR, for difficult biliary cannulation in patients with protruded Type-2, Type-3, and shar-pei papilla. The investigators hypothesized that with this new technique cannulation success will be higher, procedure time will be shorter and the adverse events will be lower versus NKF technique.
The aims of this study are to compare the needle knife fistulotomy (NKF) technique versus the partial ampullary endoscopic mucosal resection (PA-EMR) technique in patients with difficult biliary cannulation and to assess the incidence rate of complications between these cannulation methods.