The device i.e. electro surgical instrument (10), has a sleeve (32) with an inner electrode arrangement i.e. sleeve electrode, over which one of hollow organs lie, and an external electrode arrangement i.e. iris diaphragm, lying radially against other hollow organ. The diaphragm has multiple lamellas movable against each other via adjusting elements (52, 52'). Interior edges of the lamellas form a passage opening in a closing condition. A gap is formed between the lamellas in an opening condition, where organs are connected together via the gap and are guided outwards from the opening.