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Spinal Stenosis: Cervical and Lumbar Nerve CompressionStewart G. Eidelson, M.D.
This is Part One of a two-part article designed to answer typical questions patients have about spinal stenosis including the causes, symptoms, and diagnostic process. Part Two answers questions about treatment and recovery.
What is Spinal Stenosis?
A clue to answering this question is found in the meaning of each word. Spinal refers to the spine. Stenosis is a medical term used to describe a condition where a normal-size opening has become narrow. Spinal stenosis may affect the cervical (neck), thoracic (chest), or lumbar (low back) spine. The most common area affected is the lumbar spine followed by the cervical spine.
Are there particular spinal structures that are affected?
Yes. To help you to visualize what happens in spinal stenosis, we will consider a water pipe. Over time rust and debris builds up on the walls of the pipe thereby narrowing the passageway that normally allows water to freely flow. In the spine, the passageways are the spinal canal and the neuroforamen. The spinal canal is a hollow vertical hole that contains the spinal cord. The neuroforamen are the passageways that are naturally created between the vertebrae through which spinal nerve roots exit the spinal canal. See Figure 1.
The spine's bony structures encase and protect the spinal cord. Small nerve roots shoot off from the spinal cord and exit the spinal canal through passageways called neuroforamen.
Figure 2 is an artist's illustration of lumbar spinal stenosis. Notice the narrowed areas in the spinal canal (reddish-colored areas). As the canal space narrows, the spinal cord and nearby nerve roots are squeezed causing different types of symptoms. The medical term is nerve compression.
Figure 2. Lumbar spinal stenosis.
What causes Spinal Stenosis?
Some people are born with this narrowing or have a genetic tendency to develop spinal stenosis. For most people though the condition is found in patients over the age of 50. Usually spinal stenosis develops gradually as a result of aging and everyday wear the tear.
As the body ages, microscopic changes occur at the cellular level. The ligaments in the spine may thicken and harden, joints enlarge, and bone spurs (called osteophytes) form. A bulging or herniated disc is common. Most rare is a spinal tumor or spondylolisthesis; this condition develops when one vertebra slips forward onto another.
Any of these conditions can cause spinal stenosis by reducing the size of the space where the spinal cord and/or nerve roots are located. The result is nerve compression and a variety of symptoms.
What symptoms are associated with Spinal Stenosis?
First, the actual narrowing of the spinal canal or neuroforamen does not cause symptoms. Symptoms develop when the spinal cord or nerve roots are compressed; squeezed or trapped. Compression causes inflammation and inflammation can cause pain, weakness, and numbness. Symptoms vary depending on the location of the spinal stenosis. For example, the symptoms of cervical spinal stenosis primarily affect the upper body and lumbar spinal stenosis the lower body.
Cervical Spinal Stenosis
Pain, burning or tingling sensations, feelings of pins and needles, weakness or numbness in the shoulders, arms, hands.
Clumsy hand movement.
Gait (the way a person walks) may be affected.
Lumbar Spinal Stenosis
Pain, sciatica, tingling sensations, feelings of pins and needles, weakness or numbness in the buttocks, legs, calves.
Symptoms may increase when walking and decrease when sitting, bending forward, or lying down.
Rare: Bladder or bowel problems, paraplegia.
How is Spinal Stenosis diagnosed?
Similar to other medical disorders, the diagnostic process includes a complete patient history, and physical and neurological examination. You will be asked to describe your symptoms, when the condition started, activities that aggravate or alleviate symptoms, and the result of previous medications taken and therapies tried to treat the disorder.
During the physical and neurological examination the doctor will feel your spine and test your reflexes. Further, he will test your balance while watching you walk normally, on tip toes and heels. To determine how much motion you have in your spine, you may be asked to bend forward, backward, and side to side. These and other movement and reflex tests help to rule out loss of extremity reflexes, muscle weakness, and loss of feeling. The extremities are your arms and legs.
Can the doctor tell it is Spinal Stenosis just from an examination?
Depending on doctor's findings, other tests may be needed to confirm the diagnosis. These tests include:
X-Ray: An x-ray is the most common test performed and shows the structure of the spinal bones (vertebrae) and can detect bone spurs.
Sample X-Ray detects a spinal fracture.
MRI (Magnetic Resonance Imaging): MRI provides a highly detailed, three-dimensional image of the spine. The spinal cord, nerve roots, and spaces are clearly defined.
Sample MRI detects a spinal fracture.
CAT Scan (Computerized Axial Tomography): A CAT Scan renders images of bone better than nerves and is often used to show the shape and size of the spinal canal.
Sample CAT Scan detects a spinal fracture.
Myelogram: Using x-ray and a special liquid dye that is injected into the patient intravenously, a myelogram helps to define where there is pressure on the spinal cord or nerve roots from a herniated disc, bone spurs, or a tumor (rare).
Sample Myelogram detects a cervical herniated disc.
Bone Scan: This safe test uses a radioactive material that is injected into the patient. The material attaches itself to bone and helps to detect fractures, tumors, infections, and osteoarthritis. The doctor usually relies on other tests in conjunction with a bone scan.
Sample Bone Scan.
All illustrations are courtesy of www.spineuniverse.com