Congenital - Some people are born with relatively tight spinal canals (for their age). They are a bit more likely to have symptoms if #2 or #3 below occur, because the nerves have less space to move away whatever is putting pressure on them.
Acute - Anything that enters the spinal canal relatively quickly. The most common problem is a herniated disc, but fractures, cysts, and tumors can also occur.
Degenerative - the most common form. Arthritis builds up around the nerves and slowly causes symptoms.
Nerves do not like any pressure on them whatsoever. The body protects them by encircling them initially with water (cerebrospinal fluid), and later by bone. The bony protection can become a problem when there is pressure within the spinal canal.
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Mild Stenosis: An axial T2 MRI view of the spine showing very minimal narrowing of the spinal canal. |
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Moderate Stenosis: The normal disc (blue) and areas of narrowing (red & yellow). The pressure from the discs, facets, and ligamentum flavum causes a “V” shaped pattern. |
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Severe Stenosis: There is very little space for the nerves. |
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Congenital stenosis does not need treatment, unless an acute or degenerative process occurs. For acute stenosis, it depends on the problem. Herniated discs and facet cysts are treated in a similar way. Tumors and fractures require an evaluation by a specialist right away.
Degenerative spinal stenosis is initially treated the same as a herniated disc. The only difference is that the body cannot reabsorb arthritis like it can a herniated disc, so the process tends to slowly get worse. Patients often have good periods when they follow their exercise programs. When spinal stenosis becomes symptomatic, leg pain tends to occur more often.
The goal of surgical treatment is to remove the pressure off the nerves. When possible, this can be performed through minimally invasive procedures (laminotomy vs. laminectomy). When instability of the bones is a major part of the problem, sometimes a fusion is necessary.