Spinal stenosis is a narrowing of the open spaces of the spine. This puts pressure on the spinal cord and the nerves that travel through or branch out from the spinal cord. Spinal stenosis occurs most often in the neck and the lower back.
Spinal stenosis is most commonly caused by changes in the spine related to aging.
Many people have no signs or symptoms of spinal stenosis. When symptoms occur, they often start gradually and worsen over time. Symptoms vary, depending on the location of the stenosis and can cause pain, numbness, muscle weakness or cramping, and problems with bladder or bowel function.
Location of the stenosis:
- In the neck is narrowing in the upper spine and can cause numbness, weakness or tingling in the leg, foot, arm or hand. In severe cases, nerves to the bladder or bowel may be affected, leading to incontinence.
- In the lower back is narrowing in the lower spine and can cause pain or cramping in the legs when the person stands for long periods of time or walks.
Some people are born with a small spinal canal. However, most spinal stenosis occurs when something happens to narrow the amount of space available within the spine. Causes of spinal stenosis may include:
- Overgrowth of bone – spinal bones or bone spurs can grow into the spinal canal
- Herniated disks – soft cushions between the vertebrae tend to dry out with age and some of the soft inner material escapes. The discs then press on the spinal cord or nerves
- Thickened ligaments – the cords that hold the bones of the spine together become stiff and thick over time. Thickened ligaments can bulge into the spinal canal
- Arthritis – the cartilage breaks down and the bones and discs rub against each other
- Tumors – abnormal growths can form inside the spinal cord and press on the spinal cord or nerves
- Spinal injuries can cause dislocations or fractures of the spinal cord and put pressure on the spinal cord or nerves.
Most people with spinal stenosis are above the age of 50. If younger people develop spinal stenosis, the cause is typically a genetic disease affecting bone and muscle development.