What Is Spinal Stenosis?
The narrowing of the spinal canal, called spinal stenosis, can happen as a result of the degeneration of both the facet joints and the intervertebral discs. In this condition, bone spurs, called osteophytes, which develop because of the excessive load on the intervertebral disc, grow into the spinal canal.
The facet joints also enlarge as they become arthritic, which contributes to a decrease in the space available for the nerve roots. The ligaments of the spinal column, especially the ligamentum flavum, become stiff, less flexible and thicker with age, which also contributes to spinal stenosis. These processes narrow the spinal canal and may begin to impinge and put pressure on the nerves roots and spinal cord, creating the symptoms of spinal stenosis.
Stenosis may occur in the central spinal canal (central stenosis) where the spinal cord or cauda equina are located, in the tract where the nerve root exits the central canal (lateral recess stenosis) or in the lateral foramen (foraminal stenosis) where the individual nerve roots exit out to the body.
Some distortion of the spinal canal will occur in virtually every person as they age, but the severity of the symptoms will depend on the size of a person’s spinal canal and the encroachment on the neural elements. The rate of deterioration varies greatly from person to person, and not everyone will feel symptoms.
Spinal stenosis may be caused by a number of processes that decrease the amount of space in the spinal canal available for the neural elements. Degenerative causes are the most common, but there are a few unusual causes of stenosis. These include calcium pyrophosphate crystal deposition, amyloid deposition, and intradural spinal tumors.