Duodenal Biliary Drainage Procedure

What is duodenal biliary drainage? Duodenal biliary drainage is a little-used procedure that sometimes can be helpful in diagnosing gallstones. How is duodenal biliary drainage done? For duodenal biliary drainage, a thin plastic or rubber tube with several holes at its tip is passed through a patient's anesthetized nostril, down the back of the throat, through the esophagus