A bodily lumen, such as a blood vessel, can be treated by forming a structural support in situ within the bodily lumen. This can be done by ejecting a formulation that includes a polymer that solidifies over a period of time, such as due to DMSO exchange or photocrosslinking. This can also be done by cooling a formulation until it freezes in situ. The structural support can also be made from a plaque which is already present in the bodily lumen. The plaque can be compressed by a balloon catheter and cooled so that it hardens and thereby forms the structural support. The bodily lumen can also be treated using a preformed structural support made of ice, for example frozen isotonic saline, or a fast degrading polymer, such as PEG. The preformed support is created outside of the bodily lumen, and then transported on a catheter to the treatment zone.
