Surgical implants are configured for placement posteriorly to a spinal canal between vertebral bodies to distract the spine and enlarge the spinal canal. The device permits spinal flexion while limiting spinal extension thereby providing an effective treatment for treating spinal stenosis without the need for laminectomy. The device may be used in the cervical, thoracic, or lumbar spine. Numerous embodiments are disclosed, including elongated, length-adjustable components coupled to adjacent vertebral bodies using pedicle screws. The device is configured for placement between adjacent vertebral bodies and adapted to fuse the lamina, facet, spinous process or other posterior elements of a single vertebra. Preferably, the device forms a pseudo-joint in conjunction with the non-fused vertebra. Alternatively, the device could be fused to the caudal vertebra or both the cranial and caudal vertebrae.
