A stent, for example, is provided with a plurality of frame elements, which may have an undulating form. The stent is provided with a plurality of magnetic elements between adjacent stent elements. The magnetic elements on opposing circumferentially facing portions or sides of the strut elements have the same polarities so as to produce repulsive forces biasing the stent structure into a radially expanded configuration. The magnetic elements provide an alternative opening force on the stent, enabling the stent to be made of struts of thinner and weaker material or of a non-sprung material. The magnetic elements also provide a constant opening force in order to retain the stent reliably in position within a vessel. The stent could be made of a biodegradable material.
