spinal stenosis

Spinal stenosis is a narrowing of the space inside the bony spine (see Figure 7 below), which sometimes results in pressure on the spinal cord and peripheral nerve roots from the spinal cord. The Social Security Administration most commonly sees such cases in claimants who have severe osteoarthritis of the lower spine. Spinal stenosis can be worsened by bulging or herniated disks (HNPs) (see Figure 8 below) and spondylolisthesis.

Figure 7: Spinal stenosis with a narrowing of the spinal canal.

Figure 8: Spinal stenosis caused by a herniated disk and osteoarthritis.

-Spinal stenosis most commonly involves the lower back, specifically the area somewhere between the 3rd lumbar vertebra and the beginning of the sacrum (L3-4, L4-5, and L5-S1 levels). Less frequently, the neck (cervical spine) may be involved with spinal stenosis; its presence in the upper back (thoracic spine) is rare.

-Spinal stenosis is one of many possible causes of damage to the spinal cord (myelopathy). Myelopathy may be irreversible. Surgical decompression of the spinal cord may be necessary for severe cases, but even after surgery symptoms may not improve.

-In addition to osteoarthritis, causes of spinal stenosis include congenital spinal deformities (scoliosis, kyphosis, or congenital skeletal dysplasias like achondroplastic dwarfism); acquired deformities such as post-traumatic spinal fractures; inflammatory spinal diseases like ankylosing spondylitis; or stenosis may be of unknown cause. Tumors or infection present possible reversible causes of lumbar stenosis.

-Spinal stenosis can be seen on imaging studies such as myelography, CT, and MRI scans. But myelography and CT scans can miss some types of stenosis.

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