Posterior dynamic stabilization of the spine

An interspinous vertebral implant comprises a resiliently compressible body that is adapted for position between adjacent superior and inferior spinous processes, and an anchoring member that is affixed to the superior and the inferior spinous processes posterior to the resiliently compressible body. The anchoring member provides a compressive force while the resiliently compressible body provides a distraction. Without being bound by any theory, it is believed that the combination of the distraction and compressive forces created by this type of interspinous vertebral implant results in a rotational moment, which alleviates compression on the intervertebral disk.