by David Borenstein, MD
A recent review of 24 studies reported that there was no “gold standard” for the diagnosis of lumbar spinal stenosis. The results of this report mean that spinal stenosis cannot be diagnosed using laboratory and imaging tests alone; a complete diagnosis requires a doctor’s review of specific complaints and physical findings. The diagnosis can then be confirmed by imaging tests showing compression of spinal nerves.
Assessing symptoms. In making a diagnosis, a doctor has to consider where and when symptoms appear. Pain, weakness, or numbness caused by spinal stenosis typically occurs only in the legs and only after walking a certain distance. A person who is examined after being seated for a while may not exhibit any symptoms.
Considering other conditions. The doctor will also consider other common causes of leg pain in older people. A condition called vascular claudication, in which the blood vessels in the legs narrow and cut off blood flow, is one possible cause of leg pain. In people with vascular claudication, the leg pain is brought on by increased physical activity. But in contrast to spinal stenosis, in which the pain radiates from the back to the foot, vascular claudication causes pain to radiate from the foot up toward the thigh. Also, people with spinal stenosis are able to ride a stationary bicycle without limitation, whereas people with vascular claudication experience calf pain when riding a stationary bicycle.
Hip arthritis may also be mistaken for spinal stenosis. It can cause pain while walking that radiates from the low back to the knee. Hip arthritis rarely causes lower leg pain unless knee arthritis is also present. To distinguish between hip arthritis and spinal stenosis, a doctor can have you move your hip joint without moving the lumbar spine. If this causes pain, hip arthritis may be the problem. X-rays of the hip joints are also helpful in confirming the presence of arthritis.
Another common problem in older people that can mimic lumbar spinal stenosis is peripheral neuropathy, a nerve problem that causes tingling or numbness in the feet (and sometimes the hands). Unlike the symptoms of spinal stenosis, the symptoms of peripheral neuropathy do not improve with a change in position. People who experience tingling in the feet while lying in bed are more likely to have peripheral neuropathy.
Imaging tests. Doctors use various imaging tests to help confirm a diagnosis of spinal stenosis. However, these tests have their limitations. For example, a plain x-ray of the lumbar spine of most people aged 60 or older will show that the intervertebral disks have degenerated and the cartilage on the joints connecting adjacent vertebrae has worn away. But these changes do not mean that a person has spinal stenosis. Many older people have these changes to the spine without experiencing pain. For this reason, an x-ray is not the best tool for pinpointing the specific area of the spine that is causing the symptoms.
More powerful imaging tests are often more helpful. Magnetic resonance imaging (MRI) scans use magnets to identify areas of nerve compression in the central or lateral portion of the spinal canal, as well as in the neural foramina. In general, MRI is better at detecting damage in soft tissues like the disks and nerves than in the bones. Also, people with a pacemaker or other electrical device implanted in their body cannot have MRI scans because of the effect of the magnets on the implanted device.
Another imaging technique, called computed tomography (CT), uses special x-rays to form sharp images of bones. CT can visualize the shape and size of the spinal canal as well as the nerves within it. Unlike MRI, CT can be used by people who have an implanted electrical device.
While MRI and CT scans are better than x-ray at pinpointing the exact part of the spine that is compressing a nerve, having this information is not essential unless you and your doctor are considering surgery as treatment for your symptoms. Surgical treatment requires that the doctor identify the problem causing area so that surgery can be performed on the appropriate part of the spine.
The treatment of lumbar spinal stenosis requires careful clinical judgment. The doctor will try to weigh the severity of the person’s complaints against the benefits and risks of the available therapies. The main options for treatment are weight loss, exercises, medicines, spinal injections, and surgery. No therapy works for everyone, and you and your doctor may determine that some options are not worth the risks.
One problem in prescribing treatment is that when people have spinal stenosis, it is rarely their only medical problem. Medical problems that exist alongside other medical problems are called comorbidities. Common comorbidities of spinal stenosis include cardiovascular problems such as heart attack, congestive heart failure, and stroke. Lung problems that cause shortness of breath are also relatively common. Another frequent comorbidity is diabetes, which can lead to peripheral neuropathy and blood vessel problems.
Last Reviewed on July 27, 2011
David Borenstein is a rheumatologist and Clinical Professor of Medicine at The George Washington University Medical Center in Washington, DC. Over the course of his 32-year career, his major medical interest has been the evaluation and treatment of spinal disorders.
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