Understanding the Progression of Cervical Spondylosis to Spinal Stenosis

Cervical spondylosis is a condition in which the joints between the vertebral bones of the spine degenerate, potentially progressing to a medical problem known as cervical spine stenosis. The cervical spine is the section of the spine that starts at the base of the skull, travels down the neck and ends at top of the shoulders where the thoracic spine then begins.

Each of the bony vertebrae of the spine has a hole in its center. This center hole is known as the vertebral foramen or neural canal. With each vertebra stacked on top of one another to comprise the spine, the vertebral foramen actually create a hollow cylinder that contains the spinal cord.

The spinal cord is a cohesive mass of neurons that exits from the brain and travels down the back. The spinal cord has individual roots of neurons that exit the bony spine at each vertebral level. The spinal cord ends by splitting completely into individual neural roots much like a horse tail. This section of the spinal cord is called the cauda equina, and occurs in the lower back area.

The spinal cord is soft and, therefore, compressible, unlike the bones that encase it. When the spinal vertebrae degenerate, as happens with age or trauma, the center neural canal can get smaller. As mentioned above, the degeneration of cervical spine vertebral bones is called cervical spondylosis. However, when cervical spondylosis progresses to the point that the neural canal narrows, the condition is called cervical spine stenosis.

The narrowing that occurs in cervical spine stenosis can cause significant neurological problems by pinching the spinal cord as it attempts to transmit neurological information to and from the brain and body.

Other conditions beside the osteoarthritis associated with aging and/or past trauma can cause cervical spine stenosis. Herniation of a cervical disc between the vertebrae can compress the spinal cord, as can tumors, infections, rheumatological disorders such as ankylosing spondylitis, and even osteoporosis.

Additionally, some individuals are born with abnormalities of the bony cervical spine. Individuals with these congenital bone abnormalities are at a higher risk of developing cervical spine stenosis due to instability of the intervertebral joints in the neck.

While cervical spine stenosis has the potential to compress the spinal cord and cause significant neurological injury, there are many individuals with a narrowing of the spinal canal who do not have symptoms. Some people with asymptomatic cervical spine stenosis may remain symptom free for their entire lives. However, all people with cervical spine stenosis are at a higher risk of spinal cord impingement. These individuals should maintain an active relationship with their physician so that early signs of spinal cord impingement may be detected and addressed, potentially avoiding permanent disability.

Sources:

Isaac, Z MD. Evaluation of the patient with neck pain and cervical spine disorders. UpToDate Online 17.3. June 4^th, 2009.