The invention relates to a medical device for local application of a fluid(97), comprising aflexibly deformable external hose (1)； whereby the external hose (1) comprisesmultiplethrough-going openings (2), whereby at least one of them is arranged in thearea of a first end(3) of the external hose (1)； a flexible internal hose (4), whereby at leastsections of the internalhose (4) are arranged on the inside of the external hose (1), whereby theinternal hose (4), inan expanded state, has an external diameter that is at least equal to theinternal diameter ofthe external hose (1), such that it closes the openings (2) of the externalhose (1), whereby theexternal diameter of the internal hose (4) can be transitioned from theexpanded state into aradially contracted state, such that the openings (2) are being exposed； aconnection (5) thatfirmly connects the external hose (1) and the internal hose (4) to each otheron the first end (3)of the external hose (1),and closes them in fluid-tight manner； and aconnector (6) for supplyingthe fluid (97) into the intervening space between the external and theinternal hose.The invention also relates to a hose system for designing a device of thistype, a method forshortening a hose system of a device of this type, and a method for operatinga device of thistype.
