Spinal stability is required to maintain posture and protect the nerve roots and spinal cord.
Please review the Lumbosacral spine anatomy section for more information.
Spinal instability occur when one spinal segment moves more than it should or when the normal alignment of the spine is disrupted.
Instability may develop gradually over many years due to arthritis and disc degeneration, or it may occur after an injury, fracture, or previous spinal surgery.
Major Diagnosis Types
Below are the major types we see in our clinic. Click on available links to learn about our approach to the problems.
Adjacent Segment Disease
Adjacent segment disease occurs when the spinal levels next to a previous fusion develop accelerated wear and tear over time.
These changes may lead to disc degeneration, facet arthritis, spinal stenosis, instability, or deformity.
Pseudarthrosis
A pseudarthrosis is a spinal fusion that has failed to completely heal. It is sometimes called a nonunion.
After spinal fusion surgery, bone is placed between vertebrae with the goal of forming one solid piece of bone. Screws and rods maintain stability while the fusion heals.
If adequate bone growth does not occur, continued movement can remain at the surgical level. This problem can cause symptoms that may require additional treatment.
Spondylolisthesis
Condition where the vertebral body slips forward due to trauma, defect, or degeneration.
Can cause pain or neurologic symptoms from nerve compression
Minor Diagnosis Types
These terms are often encountered, but are either less often treated or described within one of the above diagnoses.
Retrolisthesis
Retrolisthesis occurs when a vertebra slips backward relative to the vertebra below it.
Although usually less common than forward slippage, retrolisthesis may contribute to spinal instability and narrowing of the spinal canal or neural foramina.
Segmental Instability
Segmental instability refers to excessive motion between two vertebrae that causes pain, nerve irritation, or abnormal movement.
Instability may result from degeneration, injury, or previous surgery.
Spondylolysis (Pars Defect)
Spondylolysis is a stress fracture or defect involving the pars interarticularis, a portion of the vertebra that helps stabilize the spine.
Some pars defects heal without causing problems, while others may progress to spondylolisthesis.