Instrumentation has been developed specifically to improve rates of successful spinal fusion. Because bone tends to fuse more effectively in an environment where there is little motion, instrumentation works by limiting the motion at the fused segment. Spine surgery instrumentation can be placed posteriorly in the lamina, facets, and pedicles (usually C2 or C7).

Posterior cervical instrumentation is used to hold the cervical motion segments in the neck together so that they can fuse. The surgery is performed from the back of the neck and is used for treatment of cervical disc herniation, degeneration and fractures, or cervical deformities.

Posterior (pedicle)
Pedicle screws provide a means of gripping onto a vertebral segment from posteriorly and limiting its motion. The screws are placed at two or more consecutive spine segments, and then a rod or plate is used to connect the screws. The screws, plates and rods are generally made with titanium. After the bone graft grows, the instrumentation no longer needed for stability and may be safely removed with a subsequent back surgery. However, most surgeons do not recommend removal. Need diagram!!

Posterior (lamina or spinous process)
Fixation to the posterior processes of the spine can be obtained by passing wires under the lamina. Alternatively, either wires or hooks can be placed to hold onto the lamina. Also, wires can be placed in spinous processes to hold adjacent segments together.

Placement of the screws involves some risk to the vertebral artery and the exiting nerve root, so there is added risk (versus wiring procedures), but better fixation of the spine is achieved.