SPINAL STENOSIS – one manifestation of arthritis in the spine. The tunnel or canal through the spine where the spinal nerves run becomes narrow. Bony growths on the vertebrae narrow this opening and cause pressure on the spinal cord and/or nerves.
Patients may have pain, with numbness, tingling or weakness to the arms or legs. Spinal stenosis may occur at any level of the spine but is more common in the lumbar and cervical spine. In the same way that scale develops over a period of many years on the inside of a lead water pipe eventually leading to obstruction to the flow of water, spinal stenosis is a gradually evolving “blockage” to the spinal canal in either the neck or lower back.
The blockage is caused not by scale or rust but arthritis of the joints of the spine. As with arthritis elsewhere in the body, the effected joints become enlarged by the development of additional bone at their edges.
In the spine this means that more bone is present to reduce the available space for the spinal nerve as they pass through their tunnel in the centre of the back or neck. Often the process is slowly evolving and the associated reduction in mobility may be almost imperceptible, occurring over many years rather than weeks or months. It may be difficult, in fact, for an individual to be aware of how difficult their mobility has become by comparison to what it was in years gone by. Although slow in its development, the problem tends to be progressive.
In the cervical spine (neck), tension of the spinal cord is generally regarded as a more serious issue than a similar process with occurs in the lumbar spine (low back). The spinal cord generally tends to be less tolerant of compression and the difficulties which occur with walking, in particular, may be hard to reverse with treatment once the spinal cord has become injured through long standing compression.
For this reason early treatment for spinal cord compression in the neck is generally advisable. It should be realised that spinal cord compression is mostly a very different process to the pinching of one single nerve in the neck due to a prolapsed disc. Spinal stenosis often occurs in the elderly and prolapsed discs often occur in younger patients. Compression of the cervical spinal cord through the neck leads to a condition known as cervical myelopathy, the symptoms of which are outlined below.
- Pain in the buttocks, thighs or calves that is worse with walking or exercise
- Numbness in the buttocks, thighs or calves that is worse with standing, walking or exercise
- Back pain that radiates to the legs
- Weakness or “uselessness” of the legs
- Leaning on a shopping trolley in the supermarket
- Feeling of “creepy crawlies” or “walking on cotton wool”
- Tendency to lean forward when walking
- Difficulty walking down stairs
- Imbalance when walking
- Difficulty in fine use of hands – e.g. writing becomes large or messier, difficulty in doing up buttons.
Often there are few signs of spinal stenosis externally. Often the patients are elderly and may stand with a stooped posture and a forward bend. Often the patient requires a walking stick. As the spinal nerve compression generally occurs with walking or with exercise, at rest people often have very few signs of the underlying problem. There may be some asymmetry of reflexes or subtle weakness in muscle groups of the legs. There may also be subtle changes to the feeling in the skin of the lower legs.
The diagnosis is mostly made on x-ray findings and other scans.
- An x-ray of the spine shows degenerative changes and narrowed spinal canal
- A spine MRI or spinal CT scan shows spinal stenosis
- An EMG may show active and chronic neurological changes
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