Spinal stenosis

Symptoms and causes

Spinal stenosis happens when the space inside the spine is too small. This can put pressure on the spinal cord and nerves in the spine. Spinal stenosis happens most often in the lower back and in the neck.

Some people with spinal stenosis have no symptoms. Others may have pain, tingling, numbness and muscle weakness. Symptoms may get worse over time.

Spinal stenosis becomes more common with age. The condition often is linked to wear-and-tear damage in the spine due to arthritis. Medicines and physical therapy may help ease symptoms of spinal stenosis. People who have serious spinal stenosis may need surgery.

Surgery can make more space inside the spine. That can ease the symptoms caused by pressure on the spinal cord or nerves. But surgery can't cure arthritis, so arthritis pain in the spine may last even after surgery.

In many people, spinal stenosis doesn't cause any symptoms. When symptoms do happen, they typically start slowly, and they can get worse over time. Symptoms depend on which part of the spine is affected by spinal stenosis.

Herniated disk and bone spurs on spine

As the spine ages, bone spurs or herniated disks are more likely to form. These conditions can shrink the amount of space available for the spinal cord and nerves in the spine.

The spine is made of spinal bones stacked in a column from the skull to the tailbone. They protect the spinal cord and nerves. The spinal cord runs through an opening in the middle of the spine called the spinal canal.

Some people are born with a small spinal canal. But most spinal stenosis happens when something shrinks the amount of open space within the spine. Causes of spinal stenosis include:

• Bone spurs. Wear-and-tear damage from arthritis can cause extra bone to grow on the spine. This makes bone spurs that can push into the spinal canal.
• Herniated disks. Disks are soft cushions that act as shock absorbers between the spinal bones. If part of the disk's soft inner material leaks out, it can press on the spinal cord or nerves.
• Thick ligaments. The strong cords that help hold the bones of the spine together can become stiff and thick over time. Thick ligaments can push into the spinal canal.
• Spinal injuries. Car accidents and other trauma can cause spinal bones to break or move out of place. Swelling of nearby tissue right after back surgery also can put pressure on the spinal cord or nerves.
• Tumors. Rarely, tumors can form inside the spinal canal.

Age is the main risk factor for spinal stenosis. Most people who have spinal stenosis are older than 50. Younger people might be at higher risk of spinal stenosis if they develop arthritis at an early age or if they have other conditions that affect the spine.