Posterior joint replacement device

1. A prosthetic device for placement in an intervertebral disc space defined between an upper vertebra and a lower vertebra to provide articulating motion to the upper and lower vertebrae, comprising:

an upper articular portion configured to be at least partially disposed in the intervertebral disc space, the upper articular portion including an upper posterior portion configured to be disposed at a location posterior of the intervertebral disc space;

a lower articular portion configured to be at least partially disposed in the intervertebral disc space and configured to cooperate with the upper articular portion to provide articulating motion to the upper and lower vertebrae, the lower articular portion including a lower posterior portion configured to be disposed at a location posterior of the intervertebral disc space; and

an attachment element extending from the upper posterior portion and when implanted extends in the general direction of the spinal column, the attachment element being configured to be fastened to the upper vertebra to at least partially secure in place the upper articular portion,

wherein the upper and lower articular portions are laterally symmetric about an anterior-posterior longitudinal centerline and the attachment element is centrally aligned about the longitudinal centerline,

wherein the attachment element is connected to the upper posterior portions by a movable joint centrally aligned about the longitudinal centerline, and

wherein the upper and lower posterior portions extend in a substantially parallel direction when the prosthetic device is in a neutral position.

2. The prosthetic device of claim 1 , including a fastener configured to fasten the attachment element to at least one of the upper and lower vertebrae.

3. The prosthetic device of claim 2 , wherein the fastener adjustably connects to the attachment element.

4. The prosthetic device of claim 2 , wherein the fastener is configured to align substantially along the centerline of said one of the upper and lower articular portions.

5. The prosthetic device of claim 2 , wherein the fastener includes a bone anchor screw.

6. The prosthetic device of claim 1 , wherein the attachment element is configured to receive a fastener at a plurality of selectable locations.

7. The prosthetic device of claim 1 , wherein the joint provides a degree of freedom to the attachment element.

8. The prosthetic device of claim 1 , wherein the attachment element includes at least one aperture configured to receive a fastener.

9. The prosthetic device of claim 1 , wherein the attachment element extends at least to pedicle of the upper or lower vertebrae.

10. A method of implanting a prosthetic device in an intervertebral disc space defined between an upper vertebra and a lower vertebra to provide articulating motion to the upper and lower vertebrae, comprising:

placing an upper articular portion at least partially in the intervertebral disc space, the upper articular portion having an upper posterior portion configured to be disposed at a location posterior of the intervertebral disc space;

placing a lower articular portion at least partially in the intervertebral disc space, the lower articular portion having a lower posterior portion configured to be disposed at a location posterior of the intervertebral disc space, wherein the lower articular portion cooperates with the upper articular portion to provide articulating motion to the upper and lower vertebrae, the lower posterior portion connected by a joint to an attachment element;

aligning the upper and lower articular portions about a longitudinal centerline such that the upper and lower articular portions are symmetric about the longitudinal centerline and such that the upper and lower posterior portions are substantially parallel when the prosthetic device is in a neutral position;

centrally aligning the joint about the longitudinal centerline;

positioning the joint posteriorly of vertebral bodies of the upper and lower vertebrae; and

fastening the attachment element extending from the lower posterior portion in the general direction of the spinal column to the upper vertebra outside the intervertebral disc space to at least partially secure in place said one of the upper and lower articular portions.

11. The method of claim 10 , wherein fastening the attachment element includes attaching the attachment element to a head of a fastener.

12. The method of claim 10 , wherein fastening the attachment element includes connecting the attachment element to the upper vertebra to provide flexible dampening to the articulating motion.

13. The method of claim 10 , wherein placing the upper articular portion and placing the lower articular portion are performed simultaneously.