A narrowing of the lower spinal canal
About 1 in 5 patients I operate on are suffering from a narrowing of the lower spinal canal, also known as lumbar spinal stenosis.
This condition is less well known than spinal disc herniation, but presents patients with similarly unpleasant symptoms. Patients not only suffer backache and sore legs, but also reduced mobility, which makes walking long distances agony for them. It is fairly easy to explain how these symptoms develop. No doubt you are familiar with the expression, ‘tightening the thumbscrews’. Thumbscrews were horrible torture instruments which were used in the old days to pressure prisoners into making confessions. The process involved placing a prisoner’s thumb in a vice, then tightening a screw. As the thumb got crushed harder, thus compressing the nerves in the thumb, the prisoner would experience more pain. There is little doubt that prisoners who had undergone this form of torture for a considerable period of time would experience pain for quite a while after their thumbs had been released. In much the same way, lumbar spinal stenosis develops from increasing compression of the spinal nerves. These nerves can be released through surgery. Depending on the duration and degree of the compression, patients will make some degree of recovery.
How does such a narrowing of the lower spinal canal develop?
While there are patients who were born with the condition, it is generally a condition that affects ageing persons. Our bodies change as we grow older. Some people grow broader noses in old age, while others grow larger ears. Likewise, there are people whose connective tissue and facet joints in the canal surrounding the sciatic nerves grow in volume. Noses have room to grow. However, the nerves inside our spinal canal have no room to grow, so if they do grow, they will be compressed. Like prisoners having their thumbs crushed harder and harder by torturers, patients will experience more and more pain – generally, at first, when walking.
What kind of symptoms are you experiencing?
Lumbar spinal stenosis differs from a hernia in that hernias typically present with acute backache and sore legs. Lumbar spinal stenosis has a much slower and more gradual onset. You will notice that you will gradually be able to walk less and less far. One or both of your legs will start hurting while you are walking; either your leg muscles will start cramping up or your legs will begin to feel heavy. Alternatively, you may get a burning sensation or pins and needles in your legs, so bad that you will want to stop walking just to wait for the pain to subside. Often, though, your body will prove to be quite clever; you will spontaneously wish to bend over, and you’ll find that this position will relieve your symptoms. In a way, bending forward loosens the thumbscrew. This is why you will generally be able to go on cycling even when you are having a hard time walking. While riding a bike, you will often be a little bent over, thus easing up the compressed spot in your lower spinal canal. By the same token, you will find that your pain will be less severe if you lean on your trolley while out shopping.
If your symptoms are stopping you from going about your daily life, and if all other remedies, such as painkillers and/or physiotherapy, are no longer effective, you may benefit from seeing a neurologist. The thumbscrew described above tends to be easily spotted in an MRI scan. If your symptoms are so severe that they are making you acutely unhappy, you are likely to benefit from decompression surgery (refer to the ‘lumbar spinal stenosis’ section elsewhere on this website), and a neurologist will refer you to a neurosurgeon if you are so inclined. A Dutch pioneer in this field, Professor Verbiest, who lived and worked in Utrecht all his life, was the first to discuss this disorder in great detail, back in 1973. He also came up with a way to treat it. By now the surgical technique he originated is known and performed all over the world. It is called hemilaminectomy, but never mind about the name. Chances are you’ll just want to know whether these techniques actually work. The good news is that 8 in 10 patients are able to walk significantly longer distances after the operation, without sore legs preventing them from moving about. However, the remaining two patients will unfortunately have to accept that that the nerve has been damaged to the point where it will never make a complete recovery. In the event that this should be the case for you, rest assured that I will not leave you in the lurch. In such an event I will arrange for you to see our excellent anaesthetist Dr Poell, who specialises in pain management and has many means at his disposal to make what pain you still have bearable for you. All things considered, there is a significant chance that your symptoms will be reduced, and you’ll feel intensely relieved once you’re able to walk your dog again, or buy some groceries on foot. The thumbscrews will have been released, and you will no longer feel like a prisoner of your own body.
Source picture: worthpoint.com