Spinal fusion may be moving over to make way for a new method of steadying the spine. When degenerative discs and aging bones cause chronic back pain, replacement parts may be the up and coming thing.
Artificial discs are now on the market. Replacing the discs with bone-filled cages is another new option. Cages with bone graft or metal plate is an example of an internal fixator. The nonfusion DYNESYS® Spinal System is used to stabilize one or more segments of the spine. Unlike the internal fixator, this new system restores spinal motion but leaves the discs and joints in place.
Researchers in Germany and Switzerland studied the internal fixator and the DYNESYS® system. The study was done on six cadavers (bodies preserved for study). The internal fixator and the nonfusion system were both tested in three planes of motion: bending forward and backward, bending side to side, and turning left to right. The results were compared to a healthy spine with normal motion. The researchers found that the DYNESYS® gave the spine more flexibility than the internal fixator. Still, the flexibility given by both systems is much less than the normal, healthy spine.
The researchers suggest that systems like DYNESYS® may give doctors another way to treat patients with chronic back pain. The device is implanted along both sides of the spine. It has screws, cords, and spacers. Such a nonfusion system provides the needed stability without losing all the motion.
More testing of this system is needed, with different loads placed on the spine. Applying a force like that of the muscles is one area for research. Finding a system that gives full stability and full motion is another area of study.