A device for maintaining a tract through a tissue wall having a proximal side and a distal side. The device includes a body, a retainer adjacent an end of the body which will lie on the distal side in the use orientation, and a flange adjacent an end of the body which will lie on the proximal side in the use orientation. The retainer comprises a ferromagnetic material that responds to a magnetic field to maintain the retainer in an undeployed, insertion orientation.
