Lumbar (Low Back) Dynamic Stabilization - A Patient's Guide
Traditionally, spinal fusion has been offered to patients who suffer from lumbar (low back) degenerative disc disease, spinal stenosis or spondylolisthesis. Early fusion procedures performed without instrumentation (e.g. rods) proved to be more prone to failed fusion (pseudofusion) than instrumented fusion. As metal implants were developed and used, failure rates declined. However, despite this improvement, fusion is known to significantly alter spinal biomechanics, which is a concern for causing premature disc degeneration at levels neighboring fusion, especially in young patients.
Why do metal implants affect spinal biomechanics?
Partly, because stainless steel and titanium are rigid and far less compliant than bone. These rigid implants can cause significantly more stress on the neighboring levels of the spine. Some research has shown excessive motion at the neighboring non-instrumented levels in the spine. Both of these effects are felt to contribute to premature degeneration of nearby levels, or what is termed adjacent segment disease. This degeneration can either occur in previously healthy levels, or accelerate the breakdown of levels with early signs of disease. Adjacent segment disease is associated with worsening disc disease, additional bone spur formation, and overgrowth of the spine's joints (facet joints) which can cause narrowing of the spinal canal and further nerve compression.
How is dynamic stabilization different?
Dynamic stabilization, also called flexible or soft stabilization, is a growing area of spine surgery that potentially can reduce some of the problems inherent with metal implants. The long-term goal of dynamic stabilization is to treat the current problem and simultaneously reduce adjacent segment disease.
Dynamic stabilization uses flexible materials (constructs) to stabilize the affected level or levels without transmitting excessive forces. The flexible portion of the construct limits excessive motion while allowing a degree of mobility. Dynamic stabilization also reduces the load on the spine's joints (facets) and disc space, which may reduce pain.