The new era of endoscopic ultrasound in biliary disorders.

Biliary obstruction is one of challenging biliary disorders in gastroenterology field, where this long-standing condition can also lead to portal hypertension and multi-disciplinary teamwork is usually needed to manage this problem. Biliary drainage is the primary management to prevent prolonged cholestasis. Biliary system with its thin-walled and tubular structure sometimes makes the diagnosis and therapeutic not easy to approach. Over the past 3 decades, numerous new and modern diagnostic and therapeutic modalities have been developed to manage the complex biliary problems. It is well known that endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic biliary drainage (PTBD), and surgical procedure are common procedures in managing biliary disorders. However, surgical therapy and ERCP are not always easy to perform due to several contraindications. Because of difficulty in performing these procedures or unavailability of these procedures in the facility, PTBD, as the primary non-surgical procedure of choice, has been popular due to its easy technique. Endoscopic ultrasound (EUS) has evolved significantly not only as a diagnostic tool for identification and staging, but also for interventional approaches, especially in management of biliary malignancy. Recently, EUS-guided biliary drainage (EUS-BD) and EUS-guided gallbladder drainage (EUS-GBD) are developed for managing biliary disorders. Whether EUS can be useful for managing biliary obstruction as a primary procedure is still controversial. Hence, a large number of further studies are required to validate.