Patent ID: 8128699

Claim:
An intervertebral implant for positioning between an upper vertebra and a lower vertebra, the implant comprising: an upper endplate for engaging the upper vertebra; a lower endplate for engaging the lower vertebra; a damping member disposed between the upper and lower endplates, the damping member including a plurality of chambers having a material disposed therein, wherein the material has a viscosity that is dependent on a magnetic field strength; and a plurality of permanent magnets disposed in at least one of the upper endplate and the lower endplate, the plurality of permanent magnets generating magnetic fields for controlling the viscosity of the material disposed in the plurality of chambers of the damping member, wherein the at least one of the plurality of magnets is movable between a first position where the magnetic field has a first strength and a second position where the magnetic field has a second strength greater than the first strength.