Spiral balloon catheter

A balloon catheter system comprising one or more conduits to which are attached an inner compliant balloon having a non-helical shape in its deflated state, said balloon being enclosed by an outer non-compliant or semi-compliant balloon, wherein the inner balloon is constructed such that upon inflation, said inner balloon is capable of adopting a spiral or helical conformation, and wherein said outer balloon is perforated by a first set of pores along most or all of its surface, and is further perforated by a second set of pores or openings at the proximal neck thereof, wherein the pores of said second set are significantly fewer in number and larger in diameter than said first set.