What is Dynamic Stabilization?:
If you need to undergo surgery for spinal disc problems, you may also need added stabilization of the spine to prevent additional problems. Dynamic stabilization is a surgical technique designed to allow for some movement of the spine, while maintaining enough stability to prevent too much movement.
Spinal stabilization may be required for one of three reasons:
- The movement of a worn spinal disc causes pain
- A congenital or acquired defect allows the spine to become unstable (spondylolisthesis)
- Surgery requires removal of the normal stabilizing structures of the spine
If your spine is unstable, excessive motion can cause the nerves adjacent to the spinal column to become pinched. This can lead to leg pain, numbness, and weakness. By stabilizing the spinal column, the idea is to limit abnormal motion of the spinal segments, and prevent nerve impingement.
Dynamic Stabilization vs. Lumbar Fusion:
Traditionally, stabilization of the lumbar spine was accomplished with fusion. Fusion surgery
of the spine is accomplished by stimulating bone to grow between two or more adjacent spinal segments to prevent future motion. Often metal instrumentation is used to stabilize the spinal segments while bone eventually forms between the vertebrae.
Dynamic stabilization is an alternative to fusion. The instrumentation used in dynamic stabilization is designed to control the amount of motion between adjacent vertebrae, but it does not completely eliminate this movement.
Why Dynamic Stabilization?:
One of the major problems with spinal fusion is that even when all goes well and the spinal segments fuse, problems can arise down the road. Once two spinal segments have fused, extra stresses are transferred to the discs above and below the fusion. These segments tend to wear out more quickly, which can necessitate additional surgical procedures down the road. This is especially problematic in younger, more active patients.
Dynamic Stabilization Surgery:
Dynamic stabilization surgery starts much like a typical spine fusion surgery. Once any disc problems have been addressed, your surgeon places a dynamic stabilization device to limit motion at the affected disc level. One commonly implanted device is called Dynesys.
Dynesys uses screws to anchor to the vertebrae at two adjacent spinal levels. The screws are connected with rope (to prevent excessive tension) and plastic tubes (to prevent excessive compression). Rehabilitation following Dynesys surgery varies depending on specifics of the surgical procedure and must be discussed with your doctor.
Results of Dynamic Stabilization:
It is important to note that long-term studies with dynamic stabilization have not been performed. The hope is that this procedure will help prevent some of the problems seen with spine fusion, although this has not been clearly demonstrated. In addition, there are concerns with dynamic stabilization devices, including higher rates of implant failure and loosening.
More work needs to be done to better define the role of dynamic stabilization in lumbar spine surgery. Further investigation into dynamic stabilization may help answer some of these unsolved problems.
Kelly MP, et al. "Dynamic constructs for spinal fusion: an evidence-based review" Orthop Clin North Am. 2010 Apr;41(2):203-15.
"Symposium: Dynamic Stabilization of the Lumbar Spine," Orthopedics Today International, March/April 2006.