Some patients are born with this narrowing, but most often spinal stenosis is seen in patients over the age of 50. In these patients, stenosis is the gradual result of aging and “wear and tear” on the spine during everyday activities.
There most likely is a genetic predisposition to this since only a minority of individuals develops advanced symptomatic changes. As people age, the ligaments of the spine can thicken and harden (called calcification). Bones and joints may also enlarge, and bone spurs (called osteophytes) may form.
Bulging or herniated discs are also common. Spondylolisthesis (the slipping of one vertebra onto another) also occurs and leads to compression.
When these conditions occur in the spinal area, they can cause the spinal canal to narrow, creating pressure on the spinal nerve.
The narrowing of the spinal canal itself does not usually cause any spinal stenosis symptoms. It is when inflammation of the nerves occurs at the level of increased pressure that patients begin to experience problems.
Patients with lumbar spinal stenosis may feel pain, weakness, or numbness in the legs, calves or buttocks. In the lumbar spine, symptoms often increase when walking short distances and decrease when the patient sits, bends forward or lies down.
Cervical spinal stenosis may cause similar symptoms in the shoulders, arms, and legs; hand clumsiness and gait and balance disturbances can also occur.
In some patients, the pain starts in the legs and moves upward to the buttocks; in other patients, the pain begins higher in the body and moves downward. This is referred to as a “sensory march.”
The pain may radiate like sciatica or may be a cramping pain. In severe cases, the pain can be constant.
Severe cases of stenosis can also cause bladder and bowel problems, but this rarely occurs. Also paraplegia or significant loss of function also rarely, if ever, occurs.
Before making a diagnosis of stenosis, it is important for the doctor to rule out other conditions that may have similar symptoms. In order to do this, most doctors use a combination of tools, including:
MRI (magnetic resonance imaging) - this test gives a three-dimensional view of parts of the back and can show the spinal cord, nerve roots, and surrounding spaces, as well as enlargement, degeneration, tumors or infection.
Computerized axial tomography (CAT scan) - this test shows the shape and size of the spinal canal, its contents and structures surrounding it. It shows bone better than nerve tissue.
Myelogram - a liquid dye is injected into the spinal column and appears white against bone on an x-ray film. A myelogram can show pressure on the spinal cord or nerves from herniated discs, bone spurs or tumors.
Bone scan - This test uses injected radioactive material that attaches itself to bone. A bone scan can detect fractures, tumors, infections, and arthritis, but may not tell one disorder from another. Therefore, a bone scan is usually performed along with other tests.
There are a number of ways a doctor can treat spinal stenosis without surgery. These include:
In many cases, non-surgical treatments do not treat the conditions that cause spinal stenosis; however, they might temporarily relieve pain. Severe cases of stenosis often require surgery. The goal of the spinal stenosis surgery is to relieve pressure on the spinal cord or spinal nerve by widening the spinal canal. This is done by removing, trimming, or realigning involved parts that are contributing to the pressure.
The most common surgery in the lumbar spine is called decompressive laminectomy in which the laminae (roof) of the vertebrae are removed to create more space for the nerves. A surgeon may perform a laminectomy with or without fusing vertebrae or removing part of a disc. Various devices (like screws or rods) may be used to enhance fusion and support unstable areas of the spine.
Other types of surgery to treat stenosis include the following:
If nerves were badly damaged before the surgery, the patient may still have some pain or numbness after the surgery. Or there may be no improvement at all. Also, the degenerative process will likely continue, and pain or limitation of activity may reappear 5 or more years after surgery.
Most doctors will not consider surgical treatment of spinal stenosis unless several months of non-surgical treatment methods have been tried. Since all surgical procedures carry a certain amount of risk, patients are advised to discuss all treatment options with their doctor before deciding which procedure is best.