Difficult biliary access at ERCP.

Endoscopic retrograde cholangiopancreatography allows intervention for a variety of diseases of the biliary tract. Cannulation of the bile duct is the prerequisite step for biliary intervention. Although obtaining biliary access is straightforward in many cases, it can occasionally be challenging. Multiple devices, all with additional wire-guided techniques, have been developed to aid cannulation. More advanced techniques have also been developed to aid biliary access if it is unsuccessful with standard devices. Multimodality techniques can be used if other approaches fail. This article provides an evidence-based discussion of these approaches, and provides insight into their appropriate application.