ABSTRACT
History The existence of UD has been known since at least the early 19th century, when Hey reported the first case in 1805 ( 2 ). In 1938, Hunner ( 3 ) reported three cases associated with calculi and commented on the rarity of the condition. In 1956, Davis and Cian ( 4 ) reported 50 cases, more than had been reported previously in the entire history of the Johns Hopkins hospital. They also developed a double-balloon catheter to be used in conjunction with positive-pressure profilometry to facilitate diagnosis of UD.
