A medical system is disclosed that has three basic components； a retractablesheet, a first balloon (10) that has acentrally arranged hollow, and a collapsible/expandable support structure (20)at thehollow. The first balloon (10) is for instancemounted/molded onto the exterior surface of the support structure (20). Theaggregate of support structure (20) and the first balloon(10) is positioned,and once the sheet has been retracted from the firstballoon, the first balloon (10) is inflated. The supportstructure (20) may be self-expandable or expandable by an expansion unit, suchas a further balloon arranged at its inside. The lumenof the support structure (20) is chosen to be smaller than that of a mainlumen (80). The outside diameter of the inflated firstballoon (10) is chosen to be larger than the interior diameter of the mainlumen (80). This procedure may be done using standardSeldinger technique and fluoroscopy. This makes the system user friendly andincreases patient safety,as a well established clinicalmethod may be used with some modifications according to the invention.
