LAUSR

Because the number of EUS-BD procedures should be ideally increased in failed ERCP even in high-volume centers of interventional EUS, immediate mastery of EUS-BD may be difficult. Percutaneous transhepatic biliary drainage (PTBD) was a landmark for biliary decompression in patients with obstructive jaundice when it was first introduced in the 1960s. However, because the procedure involved external drainage, the following shortcomings arose: (1) procedural pain, (2) reduction in the patient’s activities of daily living, (3) long hospital stay for tract maturation, and (4) cosmetic issues. By contrast, endoscopic transpapillary biliary stenting was an epochmaking biliary drainage procedure aiming at overcoming the issues that constrained PTBD, being a minimally invasive internal drainage technique. Thus, biliary drainage by ERCP has become the current standard technique for biliary decompression of biliary diseases. However, the success of biliary drainage by ERCP is limited by the endoscopist’s skill and the patient’s anatomic variations, such as intradiverticular papilla, surgically altered anatomy, and gastric outlet obstruction. In fact, the reported rates of failed biliary cannulation range from 3% to 10% even with expert endoscopists. Traditionally, PTBD has been an important alternative to failed ERCP. Thus, once ERCP fails, PTBD is performed unless surgical intervention is selected. In 2001, EUS-guided transmural biliary drainage (EUSBD) emerged as the 4th biliary drainage technique (ie, surgical drainage, percutaneous transhepatic drainage, endoscopic transpapillary drainage, EUSguided transmural drainage). Theoretically, the advantages of EUS-BD over PTBD include the following: (1) performance of all procedures by a single endoscopist in a single session after failed ERCP, (2) possible drainage not only for the intrahepatic bile duct but also for the extrahepatic bile duct, (3) minimal or no procedural pain, (4) no limitation of the patient’s activities of daily living, (5) short hospital stay similar to that with the ERCP procedure, (6) expectation of good drainage when a large-bore metal stent is used, and (7) cosmetically ideal procedure because of internal drainage. Although several skilled endosonographers believe that EUS-BD can be an alternative to PTBD in failed ERCP, EUS-BD cannot yet be a standard technique because of the few comparative