A prosthetic disc for insertion between adjacent vertebrae includes upper and lower plates, a core disposed between the plates, and at least one projection extending from at least one of the upper and lower curved surfaces of the core into at least one recess of one of the inner surfaces of the plates. The recess is oversize with respect to the projection to allow sliding movement of the plate over the core while retaining the core between the plates during such sliding movement. The projection(s) may include a rod extending through an axial hole in the core, multiple surface features of the core, or the like.

A prosthetic disc for insertion between adjacent vertebrae includes upper and lower plates, a core disposed between the plates, and at least one projection extending from at least one of the upper and lower curved surfaces of the core into at least one recess of one of the inner surfaces of the plates. The recess is oversize with respect to the projection to allow sliding movement of the plate over the core while retaining the core between the plates during such sliding movement. The projection(s) may include a rod extending through an axial hole in the core, multiple surface features of the core, or the like.

A prosthetic disc for insertion between adjacent vertebrae includes upper and lower plates, a core disposed between the plates, and at least one projection extending from at least one of the upper and lower curved surfaces of the core into at least one recess of one of the inner surfaces of the plates. The recess is oversize with respect to the projection to allow sliding movement of the plate over the core while retaining the core between the plates during such sliding movement. The projection(s) may include a rod extending through an axial hole in the core, multiple surface features of the core, or the like.

An expandable spacer, comprising: an axial tube having a surface, a proximal end and a distal end and a length, wherein, said surface defines a plurality of slits, said plurality of slits defining at least two axially displaced extensions, such that when said tube is axially compressed, said extensions extend out of said surface and define a geometry of an expanded spacer. Preferably the spacer is adapted to be inserted between two spinal vertebrae of a human.

Medical implant which at least partially comprises a biocompatible, electrically conductive polymer with electrical resistivity p, having the property of being able to be heated and softened by a flow of current through the polymer.

A spinal implant includes an implant body including a first endplate and a second endplate. A plurality of electrodes include at least one electrode disposed with the first endplate and at least one electrode disposed with the second endplate such that the electrodes conduct an electric current to stimulate tissue growth adjacent the implant body. Systems, surgical instruments and methods are disclosed.

An implantable device includes at least one solid structure having an external surface and a volume beneath the surface. One or more of a first conductor or set of conductors is disposed externally and/or internally on or within the structure and an array of elongate electrically conductive elements are disposed radially outwardly within the volume. A breach is detected when a conductive fluid intrudes into the volume through the surface.

Tissue implants prepared for the repair of tissues, especially avascular tissues such as cartilage. One embodiment presents an electric potential capable of receiving and accumulating desirable factors or molecules from surrounding fluid when exposed to dynamic loading. In another embodiment the implant promotes tissue conduction by retarding, restricting and controlling cellular invasion through use of gradients until competent tissue forms. Further embodiments of the tissue implants may be formed into a multi-phasic device that provides deep tissue mechanical stimulus by conduction of mechanical and fluid forces experienced at the surface of the implant.

A spinal implant adapted to be positioned within a disc space between adjacent vertebrae includes a first intradiscal element, a second intradiscal element, and a coupling mechanism. The first and second intradiscal elements include respective first and second outer surfaces adapted to be positioned adjacent an endplate of respective first and second adjacent vertebrae. The first and second intradiscal elements further include respective first and second medial surfaces that are opposite the respective first and second outer surfaces, where the second medial surface is adapted to generally face the first medial surface upon assembly of the first intradiscal element with the second intradiscal element. The coupling mechanism is associated with the first and second medial surfaces and is adapted to provide relative rotational movement between the first and second intradiscal elements in a plane generally parallel with the first and second medial surfaces.

The disclosure provides a joint replacement coupling comprising joint members with opposing joint surfaces, wherein one of the members has a magnetic portion therein which comprises an array of magnets, and the other of the members has a conduction portion therein that comprises a conductive surface. The magnets are arranged to produce a magnetic field that contacts the conduction portion. The conduction portion is optionally positioned so that at least a portion of the conductive surface contacts the magnetic field so that relative motion between the opposing joint surfaces induces current loops in the conductive surface and produces a repulsive force against the magnetic portion, thereby reducing friction between the joint surfaces, optionally separating the joint surfaces.