Abstract: A catheter assembly for insertion through a surgical opening into an interior body space for enabling a fluid to be introduced into said body space and for enabling unwanted flowable material to be drained from the body space including fluid after the same has been introduced therein. The catheter assembly comprises three separate fluid passages extending within exterior and interior end sections thereof. A balloon structure is in communication with a first passage. A second passage has outlet openings communicating therewith through which treating fluid is introduced into the body space. A third passage has drain openings communicating therewith through which fluid and/or unwanted flowable material in the body space can pass therefrom.