Causes of Spinal Stenosis
You need to know what's causing your pain (beyond the overall explanation of spinal stenosis) because that impacts your treatment options.
Primary vs. Acquired Spinal Stenosis
Doctors have 2 ways to categorize spinal stenosis. It can be primary, which means you've had it since birth—and that's considered a birth defect. Some people are born with spinal canals that are more narrow than most people's, and it may not present problems until later in life. This is a form of inherited stenosis called short pedicle syndrome. These patients are more prone to acquire stenosis in middle life.
Primary spinal stenosis isn't common, especially when compared to the other category for spinal stenosis: acquired.
Acquired spinal stenosis is the result of disease or injury to the spine, and the main types of acquired spinal stenosis will be covered in the next section.
What Causes Acquired Spinal Stenois?
The leading cause of acquired spinal stenosis is wear and tear on the spine due to aging. In fact, the most common direct cause of spinal stenosis is osteoarthritis, where the cartilage that cushions joints starts to degenerate due to age.
In young people, cartilage is smooth. As you grow older, the cartilage may become rough or may wear through completely, allowing bones to rub against each other. The body reacts to this rubbing by producing small bone growths called bone spurs (osteophytes). That's an effort to limit movement and therefore limit pain from the bones rubbing together.
That's relatively true: If you were to move less, your pain would mostly likely be less. However, you can't stop moving entirely, and less movement also reduces your quality of life. Plus, these bone spurs can create another kind of pain. In the spine, they can narrow the spinal canal (that's spinal stenosis), which may then compress your spinal cord or nerve roots.
In addition to osteoarthritis, you can also develop spinal stenosis from intervertebral disc problems. The intervertebral discs can bulge, or they can be ruptured or torn (a herniated disc). A bulging disc or fragments from a herniated disc can then protrude into the spinal canal or pinch on the nerve extending through the foramen. Ligaments connecting the vertebrae may also degenerate and allow the vertebrae to shift, which can pinch the spinal cord or nerves.
Risk factors for both osteoarthritis of the spine and for disc problems include aging, poor posture, high impact sports, and being overweight.
Injury to the spine can also cause spinal stenosis. For example, you may lift a heavy object without using proper lifting techniques. This can damage a disc or even move the vertebrae out of their normal alignment. Such injuries will put pressure on the spinal cord and nerve roots. You may also fracture part of your spine, and the fragments of bone can intrude on the spinal canal.
Any injury to the spine can also cause tissue swelling that puts pressure on the spinal cord or nerve roots, leading to spinal stenosis and back pain or neck pain.