Posterior dynamic stabilization of the spine

An interspinous vertebral implant adapted for positioning between adjacent superior and inferior spinous processes, the interspinous vertebral implant comprising:

• a distraction member comprising a compressible body positionable between the superior and inferior spinous processes and adapted to apply opposing distraction forces on an anterior portion of the superior and inferior spinous processes;
• and
• an anchoring member including a spring encompassed within the distraction member and first and second arms extending from the spring, the first arm extending posteriorly from the spring to an end of the first arm and the second arm extending posteriorly from the spring to an end of the second arm, the end of the first arm configured to be attached to a posterior portion of the superior spinous process posterior of the anterior portion and the end of the second arm configured to be attached to a posterior portion of the inferior spinous process posterior of the anterior portion;
• wherein the spring is configured to draw the ends of the first and second arms toward one another to exert a compressive force on the posterior portions of the superior and inferior spinous processes while the distraction member applies opposing distraction forces on the anterior portions of the superior and inferior spinous processes.