“Stenosis” means narrowing. Spinal stenosis is usually due to degenerative changes, however can be made worse by congenital factors, disk herniations, spinal trauma and spinal tumors.
The term “stenosis” or narrowing of the spinal canal is used in reference to the three major hollow spaces of the spine, which protect the spinal cord and/or the nerve roots.
- Narrowing involving the center of the spinal canal is termed central spinal stenosis.
- Narrowing of the “side areas” of the spinal canal below the small vertebral joints is called lateral reces stenosis or “subarticular” stenosis.
- Narrowing of the bony passages through which the nerve roots exit the spine is called foraminal stenosis.
While any one of these three spaces of the spine can be narrowed (stenotic) in isolation, there is often a combination of one or more of the above compartments which are narrowed. Your neurosurgeon will use the information obtained from your diagnostic imaging studies to match up your complaints with specific sections of spinal cord and/or your spinal nerve roots, which are affected due to compression.
The history and examination, which your neurosurgeon obtains when you are in the office are compared with the findings on the diagnostic imaging studies. In many cases, mild compressions of nerve roots and the spinal cord do not need to be treated surgically.
Cervical spinal stenosis
Significant cervical spinal stenosis may result in compression of the spinal cord in the neck. Occasionally, severe, permanent impairment of spinal cord function (myelopathy) may result. Compression of cervical spinal nerve roots may result in pain, numbness or weakness in the neck, shoulders, arms, forearms and hands.
The onset of painful or unpleasant symptoms may be slow or fast, depending on the exact circumstances. If the spinal cord is compressed by bone spurs, there may be no pain at all and the patient may be entirely unaware of the cord compression and of any impairment that it causes. The most common causes of cervical spinal stenosis are a combination of one or all of the following:
congenitally small central spinal canal diameter (the baseline spinal canal size varies from person to person)
bone spur from disk degeneration, disk bulging and bone spurs (osteophytes) (“hard” disk)
acute disk herniations (“soft” disk)
enlargement (hypertrophy) of facet joints, ligaments or laminar bone
vertebral slip and altered mobility (subluxation, spondylolisthesis)
postural abnormalities, including loss of lordosis or hyperrlordosis
95% of symptomatic cord compression (myelopathy) in people of age 55 or greater is due to cervical spinal stenosis. Cervical myelopathy is frequently not painful and occasionally can result in rapid, irreversible and devastating loss of spinal cord function. Myelopathy develops in virtually everyone, whose spinal canal cross-sectional area is reduced to under 30% of normal baseline. Motor weakness, hyperactive reflexes, sensory changes and bowel and bladder malfunction are often seen. People with cervical myelopathy from stenosis often find it difficult to maintain balance of their gait and stance and have a tendency to stumble and fall. The patients themselves may be in denial about their unsteadiness and may try to down-play the significance of their recent falls.
Depending on several factors, most importantly the main direction of the compressive force on the spinal cord (i.e. if compression is exerted from in front of or from behind the spinal cord), surgery is done from a frontal approach (i.e. anterior cervical discectomy with or without fusion and instrumentation or anterior cervical corpectomy with fusion and instrumentation) or from behind (decompressive cervical laminectomies without or with instrumented fusion).
In cases of significant cord compression, there are no good non-surgical treatment alternatives. Cervical myelopathy tends to worsen without surgery. Surgical decompression is intended to halt the progression of impairment but people with myelopathy often remain significantly disabled, even after their spinal cords have been decompressed.
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