The present invention relates to an
implant 100 which comprises a plurality of electrically-conductive closed loops (300A, 300B, 300C, 300D; 120A, 120B, 120C, 120D each constituted from a plurality of loop portions such as struts (400, 500). The loops together form apertured walls of a cage with an interior volume, and the portions in any one said loop providing electrically-conductive pathways within which eddy currents are liable to be induced when the
implant is subjected to an time-dependent external
magnetic field, with each said loop comprising at least first and second said pathways. The
implant is characterized in that the first and second pathways are arranged such that, in any particular
magnetic field, the direction of the
eddy current that would be induced in the
second pathway is the reverse of the direction of the
eddy current that would be induced in the
first pathway, so as to mitigate the tendency of the implant to function in said
magnetic field as a
Faraday cage.