Spinal stenosis is narrowing of an opening that the spinal cord or a spinal nerve passes through.
The spinal cord extends from the brain to the lower back and carries messages between the body and the brain in a top-down manner. It is encased in the spinal canal, an opening in the vertebral column that is protected by the bony parts of the vertebrae. The spinal canal is occupied by the spinal cord and the posterior longitudinal ligament, which sits between the cord and the back of the vertebra. Some people have congenitally narrow spinal canals and some people develop spinal stenosis later in life, usually due to ossification of the ligament.
The spinal nerves branch off of the spinal cord and pass through the neural foramen between the vertebrae. There’s a pair of spinal nerves between each pair of vertebrae, and they innervate the body parallel to the vertebrae. Spinal stenosis occurs when the neural foramen is narrowed or when vertebral structures encroach on the intervertebral space.
A lot of things can cause spinal stenosis. Some of them are:
· Congenital spinal stenosis–you are born with it
· Scoliosis or other progressive inherited conditions that narrow the spinal openings
· Injury that results in a slipped disc, vertebral fractures or other trauma to the vertebral column
· Medical conditions, such as Paget’s disease, where abnormal bone metabolism causes deformity of the vertebrae
· Toxins, particularly excessive exposure to fluoride in insecticides, which causes abnormal bone growth
· Degenerative diseases, such as arthritis, that are part of the aging process
Symptoms of spinal stenosis are due to nerve compression, and depend on where the compression is located.
Cervical spinal stenosis affects the nerves to the neck and arms, so the symptoms are pain and other sensory abnormalities in the neck, shoulders and arms, weakness of the shoulders or arms and difficulty grasping things. Symptoms are usually on one side or the other. If the spinal cord is involved, you can also have gait problems and loss of coordination.
Lumbar spinal stenosis involves the nerves in the lower back. Leg pain or numbness are the most common symptoms; weakness in one or both legs also occurs. With lumbar stenosis, symptoms are more likely to be on one side or the other.
Spinal stenosis is usually treated with anti-inflammatories and pain medication as long as possible. If the pain is intractable or if there are functional problems, like weakness, the narrowed openings are opened up surgically. Sometimes the surgery can be done through an endoscope instead of with traditional surgical methods.