What is Spinal Stenosis?
Spinal stenosis refers to narrowing in the spine. Your spinal canal is made up of 24 vertebrae, the sacrum (composed of five fused vertebrae), the coccyx (composed of three to five fused vertebrae), cushioning disks that lie between the vertebrae, and ligaments that hold it all together and allow movement. Running through the center of the canal is your spinal cord, which connects the brain to all parts of the body via 31 pairs of nerves that branch out from the cord and exit the column between the vertebrae. If your spinal column narrows due to aging, injury or osteoarthritis, the spinal cord or nerve roots can become compressed. This compression results in pain and numbness in the legs (if the compression is in the lower part of the spinal column) or shoulders and arms (if the compression is in the neck).
What causes it?
Spinal stenosis may be inherited or acquired.
Inherited causes of spinal stenosis include
- Small spinal canal
- Scoliosis (curvature of the spine)
- Achondroplasia, a congenital disturbance of bone formation, resulting in a peculiar form of dwarfism with short limbs, normal trunk and a small face
Acquired causes of spinal stenosis include
- Degenerative aging process: The ligaments of the spine may thicken and harden as you age. The bones and joints may enlarge; bony overgrowth (called bone spurs or osteophytes) puts pressure on the spinal cord or nerve roots.
- Osteoarthritis: This chronic degenerative condition often causes bony overgrowth (bone spurs) and disk degeneration, putting pressure on the spinal cord or nerve roots.
- Herniated disk: A bulging disk can place pressure on the cord or nerve roots.
- Spondylolisthesis: When one vertebra slips forward of another (usually from a degenerative condition or an accident), pressure can be placed on the spinal cord or nerve roots.
- Rheumatoid arthritis: This inflammatory arthritis is not a common cause of spinal stenosis, but it may cause damage to spinal ligaments and bones, particularly in the neck.
- Other less common conditions:
- Paget’s disease
- Fluorosis, when exposure to excessive amounts of fluorine or its compounds causes skeletal changes
What are the symptoms/effects?
Spinal stenosis is very common in older persons, and often does not cause any problems. It may or may not cause back or neck pain. Lumbar spinal stenosis in the lower back is more common and causes symptoms in the buttocks and legs. Cervical spinal stenosis in the neck is not as common and causes symptoms in the shoulders and arms (and sometimes legs). Symptoms are lessened when you bend forward and worsened when you bend backwards. Symptoms include:
- Sciatica (pain radiating down the leg)
- Weakness in the arms or legs
More severe spinal stenosis may result in bowel and bladder function problems. For example, cauda equina syndrome occurs when the bundle of nerves at the base of the spine (the cauda equina) becomes constricted. This compression may result in loss of bowel and bladder control, loss of sexual function, pain, weakness and loss of feeling in the legs. This is a serious condition and requires urgent medical attention.
How is it diagnosed?
To determine if you have spinal stenosis and to rule out other potential causes of your symptoms, your doctor will:
- Ask you a series of medical questions about symptoms, recent injuries and your general health.
- Conduct a physical exam to look for limitation of movement, symptoms when you bend backward and neurologic function in the arms and legs (sensation, reflexes, muscle strength).
- Order an image of your spine. Your doctor will decided which one or ones are most appropriate:
- Magnetic resonance image (MRI)
- Computerized axial tomogram (CAT) Myelogram, a radiograph of the spinal cord
- Bone scan
What are the treatment options?
When first diagnosed with spinal stenosis, your doctor will most likely try a few different non-surgical treatments to ease your discomfort.
- Posture and exercise: A forward-bending position increases the space between vertebrae and can relieve symptoms. Physical therapy and prescribed exercises can strengthen abdominal and back muscles, stabilizing the spine and providing relief.
- Nonsteroidal anti-inflammatory drugs: Aspirin, ibuprofen, indomethacin, etc., may be taken to reduce inflammation and ease pain.
- Analgesics: Acetaminophen and other pain relievers may be used to relieve pain.
- Corticosteroids: Steroid injections into the membranes covering the spinal cord reduce inflammation and treat acute pain.
- Nerve blocks: Anesthetic injections near the affected nerve provide temporary pain relief.
If these treatments do not provide adequate relief (or if you have severe spinal stenosis or cauda equina syndrome), your doctor may refer you to an orthopaedic surgeon or neurosurgeon. Surgery can relieve pressure on the spinal cord or nerves, restore spinal strength and realign the vertebrae. The two main types of surgery performed to correct spinal stenosis are:
- Laminectomy: A portion of the vertebrae called the lamina is removed to allow more space for the nerves.
- Fusion: Two or more vertebrae are joined together with a plate or screws to stabilize that portion of the spinal column.
In some cases, both of these procedures are performed in one surgery.
Who is at risk? /How can I prevent it?
Men and women over the age of 50 years are most likely to have spinal stenosis. It may occur in younger people who are born with a narrow spinal canal, who suffer a back injury or who have certain bone diseases.