A stent (30) is formed of a plurality of stent rings (24), each of which rings (24) is formed of a series of sprung sections (10) coupled to one another by flexible couplings (22). The flexible couplings (22) may be made of a biodegradable material. The flexible couplings (22) enable the stent (30) to expand to a smaller uncompressed diameter and then to expand further to a larger uncompressed diameter, by virtue of the flexible couplings (22) which allow the sprung sections to move from a partially overlapping configuration to a radially spaced configuration. The stent (30) can expand with expansion of a vessel, for example in a growing patient.
