Spinal stenosis is a condition in which there is narrowing of the spinal canal which leads to compression of the spinal cord and/or nerve roots. This can occur in any of the 3 regions of the spine (cervical, thoracic, and lumbar) but is most common in the neck (cervical) and low back (lumbar) regions.
The most common cause of spinal stenosis is arthritis. As put more and more miles on your spine, your discs tend to dry out and shrink and size (see section on degenerative disc disease). When this occurs, the space through which your nerves travels becomes smaller. Over time, you may also form bone spurs which encroach into your spinal canal and compress your nerves or spinal cord.
What Symptoms Can I Expect and How is it Diagnosed?
The most common symptoms of spinal stenosis tend to be neck or back pain accompanied by arm or leg pain (depending on which portion of your spine is affected). If your spinal stenosis is in your lumbar spine, patients tend to complain of back, buttock and leg pain which worsens with standing and sitting. It tends to be relieved with sitting, laying down or leaning over. A common scenario is someone who experiences relief of the pain when leaning on a shopping cart. This is because leaning forward tends to open up the passageways for your nerves, which results in a reduction in symptoms.
If your spinal stenosis is in your cervical spine, the symptoms you experience can be different. Most patients will have some neck pain. You may also experience arm pain to accompany it. The difference with cervical stenosis, unlike lumbar stenosis, is that it tends to affect your spinal cord rather than just the individual nerve roots. This can result in balance issues (feeling unsteady on your feet), difficulty coordinating your hands (buttoning shirts, using zippers), or dropping objects out of your hands. In severe cases, both cervical and lumbar stenosis can result in loss of control of bowel and bladder.
Spinal stenosis is typically diagnosed using an MRI. This will show narrowing of the spinal canal where the nerves travel. If you are unable to get an MRI, a CT scan can also show the narrowing of your spinal canal. Figure 3 shows two MRI cross-sections demonstrating a normal spinal canal and one with cervical stenosis. The yellow lines outline the spinal cord itself while the blue lines highlight the edges of the spinal canal (the space available for the spinal cord to float in). On the left panel is a normal canal with plenty of space around the spinal cord. The white area around the spinal cord is filled with cerebrospinal fluid which acts like a watery cushion in which the spinal cord floats. On the right panel is the MRI of a patient with spinal stenosis. As you can see, the spinal cord shape is deformed from an ellipse into a boomerang shape and there is absolutely no cerebrospinal fluid around it. The spinal canal borders (marked in blue) are so narrow, they are causing spinal cord compression.
What Are My Treatment Options?
Depending on the location and severity of your spinal stenosis, several different treatment options are available. For both cervical and lumbar stenosis, treatments can begin with modifying your activities, participating in physical therapy, and/or epidural steroid injections. Should your stenosis be severe enough to cause arm or leg weakness or should conservative treatments fail, you may be a candidate for a minimally-invasive, microscopic decompression or a minimally-invasive decompression and fusion. The treatment choice depends on the location of your stenosis, the severity of the stenosis and whether or not you have other structural issues in your spine which may necessitate a fusion.