(trapped nerve, spinal claudication)
One of the effects of aging on the spine is that the elderly are shorter than they were when they were younger, and often considerably stiffer. This is due to the fact that spinal discs are absorbed as they collapse. This change of architecture has the effect of narrowing the space available for nerves in the spinal canal.
These canals can become so tight due to the relative collapse of the spaces, that nerves are physically compressed. This is often compounded by a disc bulge in the same region. One of the important consequences of this is the reduction in the blood supply to nerve roots. This can lead to the condition of Spinal Claudication. Essentially this is pain in the nerves on exercise due to the inability of the blood supply to reach a nerve which is having to work harder by supplying exercising muscles.
Similarly within the canal itself, the collapse of disc spaces narrow the central canal due to three factors. The disc that is collapsing may often bulge into the canal reducing the volume available to nerves. At the same time, the joint to the back of the spine (facet joint) will override also narrowing the volume of the canal. The third factor is the ligament behind the spinewhich can concertina into the spine from the rear. The overall effect will produce marked narrowing of the available space for nerves, this is called stenosis. Again, not only will this produce direct compression of nerve roots but it will also reduce the ability of the blood supply to get to the nerves.
People with this condition find that their ability to function deteriorates slowly. It is often not just one event which produces symptoms. The condition can be progressive and disability can occur. The most obvious disability is the reduction in walking distance. The reason this occurs is a factor of the blood supply to the nerves as the nerve is active in walking and requires an increases blood supply which is not able to get to the tight area of the spine. This leads to a cramping in the distribution of the nerves which, as we have noted before, is called spinal claudication.
Our initial course of treatment would be non-operative. This essentially would mean treatment from either a spinal physiotherapist, osteopath or chiropractor. Often minimal change of the architecture and improvement in posture is enough to create more space for the nerves and the symptoms will settle. If this is the case and on a permanent basis, then no other treatment is required.
If this approach should fail, then there is still the option of targeted injections around nerves including a caudal epidural. The idea here is to reduce the inflammation in the nerves caused by fretting through small and tight holes. If this not sufficient to relieve the symptoms then a more invasive treatment will be required. If a caudal epidural in particular, has been successful for some months and the symptoms return, then it could be repeated. If the effect is not so long lasting then it would seem less logical to employ this as a treatment option again. If the Stenosis is regarded as severe then an injection may not be effective in any event as clearly it would be difficult to get the active ingredients in to the target area if the obstruction is very narrow.
The final option is that of spinal surgery. The idea is simply to open up the spinal canal and remove whatever is pressing upon the nerves and allow them more space. Essentially the volume of the canal is increased allowing the nerves more space and the blood vessels more opportunity to supply them. This is sometimes accompanied by a spinal fusion particularly if there is abnormal movement at the level of the stenosis. In the elderly this form of decompression is more likely to require a laminectomy as their spines are relatively fixed and the stenosis often severe. In younger patients it may be possible to do a more localised decompression using similar techniques to a discectomy.