Patent ID: 7361192

Claim:
A prosthetic device for approximating spinal disc movement comprising: a socket-base; a means for providing at least one and up to three, independent or dependent, degrees of rotational freedom positioned and secured within said socket-base; a piston for providing prismatic joint motion parallel to the axis of the piston, having a first end slidably attached to said means for providing at least one and up to three degrees of freedom; a sagittal prismatic joint element having a first side fixedly attached to a second end of said piston; a plane-bearing guide having a first side that is slidably affixed to a second side of the sagittal prismatic joint element, via a first bearing raceway, and having a second side comprising a second bearing raceway generally perpendicular to the first bearing raceway to form an element of a lateral prismatic joint; and a cap-plate which is slidably affixed to said lateral prismatic joint element; wherein said device has, at one end, means for attachment to a first vertebra and said device has, at a second end, means for attachment to a second vertebra and, when said device is implanted in the spine with said attachment means engaged with a first and second vertebra, said device forms a kinematic chain of connected, articulating components between said first and second vertebra, wherein said device has means for providing at least one and up to three independent rotational degrees of freedom and additional means for providing at least one and up to three independent linear degrees of freedom.