Patient Education: Diseases Conditions Treatments & Procedures
Spinal Stenosis
Overview
Spinal stenosis is a diagnosis we make based on a CT scan or MRI. This is not a disorder but simply a radiographic diagnosis. Many individuals develop acquired spinal stenosis as they get older, and some people more than others. In fact we remember the incidence of this finding by the simple rule that 60 per cent of individuals age 60 have spinal stenosis, 70 per cent of individuals age 70 and guess what percentage of individuals age 80 will have this?
What do we mean by stenosis?
This is a narrowing of the spinal canal. Normally the vertebrae stack on top of each other divided by the discs which cushion the front half of the vertebrae bodies. The back portion of the vertebrae is in the form of a ring or tube. Bone forms the boundaries and the bone is lined by soft tissue and ligaments. Inside this tube run the nerves which are contained in a fluid filled sac. Each nerve exits its named vertebrae level through an opening or foramen. Stenosis can occur in the central portion of the canal or at the foramen. If there is enough stenosis this can cause compression of the nerves in the canal or in the foramen.
Not all stenosis is symptomatic
In fact most people with stenosis have no symptoms. If symptoms occur we then say that person has neurogenic claudication. Now that sounds interesting! Do you remember the Roman Emperor Claudius? His name comes from claudicant, a Latin term for limp. Not to make you nervous, but neurogenic implies a nerve or nervous etiology. So when a person has neurogenic claudication, they will often limp and then bend forward (like you would to Caesar) to relieve your symptoms.
What causes Neurogenic Claudication?
When the stenosis causes enough pressure on the nerves, the nerves get claustrophobic or compressed and this blocks their blood supply. When we walk or run, the nerves need more food and oxygen just like your muscles do. Have you ever run a race and your legs ached after the second turn on the track? This is because your muscles could not get enough oxygen to maintain their exertion. You probably slowed down, (hopefully less than your competitor though) your nerves behave the same way. When they are oxygen deprived but need to work, they also hurt and you feel this in your legs.
How Does a Nerve Tell You It is Hurting?
Well you probably know this if you think back to how you felt when you strolled those two blocks, or you walked in the mall or climbed that hill that never seemed so steep before. Your nerves tell you they are compressed by causing tingling, numbness, pain, or weakness in your legs. This can be many nerves with the symptoms in both legs everywhere or a single nerve with the symptoms at a single place in your leg or foot. Treatment for this often entails a decompression of the nerves.
How Serious is This?
Neurogenic claudication is not serious, it is rarely an emergency. It affects your lifestyle. Perhaps you can't walk the golf course anymore, cannot take the dog for his walk or go shopping in the mall. Your surgeon will rule out other diagnoses that can be confused with neurogenic claudication that may be more serious. On exceedingly rare occasions, it can affect bowel and bladder function. Be sure to mention if there are any changes in urination or bowel function and if you have any other medical conditions such as diabetes. The surgery success rate is high, generally over 90 percent relief of leg symptoms in focal spinal stenosis involving one or two levels of the spine.
What about my Back Pain?
Back pain has many causes which may or may not be associated with neurogenic claudication. During your consultation, your surgeon will rule out other causes of back pain which are not associated with neurogenic claudication.
Occassionally a malalignment between the vertebrae can cause neurogenic claudication and also back pain. Malalignment from spondylolisthesis is the most common type. Other patterns of deformity are scoliosis and kyphosis. If your surgeon diagnoses these, then you may require a fusion in addition to a decompression.
