Spinal stenosis is like prostate hypertrophy or graying of the hair, it’s not a matter of if, but when: if one lives long enough, one will get it. Spinal stenosis is a favorite topic of mine because it epitomizes one my other favorite topics, the distinction between the medicine’s dichotomy of purpose: eradication of a disease and, a very different concept, the promotion of health. As much as surgery would appear to be the paradigm of eradication of disease, I will show you how, in spinal stenosis, it may be more properly conceived of a promotion of health. Spinal stenosis is not actually a syndrome, but an anatomic finding. Nonetheless, it is often described as if it were a syndrome. It should be made clear that simply having spinal stenosis is not an issue. Many people have it and have no symptoms, and thus, need no treatment. The most commonly associated syndrome is called neurogenic claudication, which means pain in the legs when you are walking. This syndrome is what some people with spinal stenosis experience.
The word “stenosis” is derived from the Greek language and means “narrowing.” The narrowing is a result of the thickening of bones and ligaments in the spine that ultimately compromises the diameter of the canal through which the nerve roots descend when passing from the bottom of the spinal cord before they exit the spinal canal and form peripheral nerves. This thickening is an example of one of the many instances in which the body’s protective mechanisms end up having an unintentionally negative effect. In this case, the hypertrophic changes in the ligaments and bones of the lumbar spine that are teleologically programmed to counter wear and tear stresses, do so at the expense of the adjacent, traversing nerve roots. Put another way, the spine “thickens” with age to protect its structural integrity and in doing so compresses the nerves that run through it.
This nerve compression can manifest as pain, numbness, heaviness, and rarely, as weakness. What makes the spinal stenosis so unique is that the pain typically arises only when the patient is standing or walking. The pain is, moreover, typically relieved by sitting or lying down. Since the patient is able to get relief by changing position, the syndrome can be, and often is, tolerated for a long time.
These somewhat unique features of spinal stenosis lead to an insidious restriction of many of the activities of daily living. The patient is often focused on the pain and is unaware of how much of his or her life has been altered by avoidance of this pain. Many patients never seek surgical treatment, as they believe that they are too old or that the gradual erosion of their repertoire of activities is a normal consequence of aging.
What patients often fail to realize, however, is that when one stops walking, two things are sure to follow: first, the body, and the heart in particular, weakens from a lack of exercise and activity. Second, the brain begins to rot from a lack of variety and stimulation. By limiting walking the patient avoids pain but loses cardiovascular fitness and brain acuity. I am certain that the unrecognized or overlooked consequences of spinal stenosis are the deconditioning and dementia that slowly sets in. Dementia may seem like an exaggeration but when the brain is deprived of the stimulation and variety that being mobile provides, it will lose some of its vitality.
The effective treatment of spinal stenosis should thus be considered as more of an empowering process, or as a process that allows for the promotion of health than as a process that eliminates a disease. In fact, since spinal stenosis is a manifestation of chronic arthritis, it can never really be eliminated.
Although there are a variety of treatments employed in treating spinal stenosis, most of them are either ineffective or merely make the patient better temporarily. They often focus on reducing the pain rather than empowering the patient. I am all for starting off with conservative treatments, but if the treatments employed only serve to delay the inevitable need to make more room for the nerve roots surgically, the treatments may be counterproductive. Some of the patients subjected to prolonged conservative treatments ultimately opt for surgery after enduring a restricted or a painful lifestyle and have the surgery in a more deconditioned state, which makes recovery more difficult. Oddly, this may be an instance where surgeons are not aggressive enough. Often the medical doctor or family member suggests to the patient that he or she is too old for surgery. This well-meant advice may paradoxically cause the patient to have a worse result.
The surgical treatment of spinal stenosis is often complicated as it has to be individualized to each patient in terms of levels of stenosis treated, amount of bone and ligament removed, and the need to fuse the decompressed levels. This is where the dialogue between doctor and patient is essential. How does spinal stenosis cause pain? To answer this question we must separate how spinal stenosis may cause back pain and how it may cause leg pain. The back pain in spinal stenosis is likely the result of the arthritis of the facet joints that caused the stenosis in the first place. There may be associated multifidus muscle weakness that can be a cause of back pain. The leg pain in spinal stenosis is not clearly understood. It may be a combination of the nerve roots being compressed and being inflamed, along with the nerve roots being deprived of oxygen or blood flow from the compression.
How does spinal stenosis improve? It doesn’t, on its own. The symptoms associated with the narrowing may wax and wane, particularly early on in the course of the disease. The overall trend is to typically worsen slowly. Physical therapy may help temporarily. Epidural steroid injections are often particularly helpful in the early stages, but these, too, offer only temporary relief. Most of the time, surgery will be needed to provide more room for the traversing nerve roots when the stenosis is severe. Perhaps, more common than neurogenic claudication, spinal stenosis manifests clinically as back pain without leg pain related to standing and walking. This leads to the often frustrating diagnosis of “arthritis” as the cause of pain The diagnosis of arthritis certainly helps the patient understand that there is no “fix,” but is often perceived by the patient as vague. As discussed previously, this diagnosis is ideal for the healthcare provider for it is a definitive diagnosis that avoids the real question, “Why does my back hurt?” It is one of the many “answers” we use that doesn’t exactly answer the question being asked.
Although, back pain caused by spinal stenosis is often treated with surgery, the results are much less predictable than are the results for leg pain caused by spinal stenosis. In the setting of back pain, the patient is better served to pursue physical therapy and pain management (see Chapter 9).
This phenomenon is so common that it has been attributed its own “sign.” The idea is that some of you will find that you can “miraculously” walk longer, without pain, while in the supermarket pushing the shopping cart around. The shopping cart is not really supplying support, but allowing you to walk with your spine in a slightly flexed position. Flexing the spine makes the spinal canal larger so that areas that are stenotic become less stenotic. The nerve roots are less compressed in this position and you have less pain when walking.