Degenerative Disc Disease
Causes of Degenerative Disc Disease in the Neck
Simple wear and tear is the usual culprit responsible for cervical degenerative disc disease. Some will suffer more than others due to lifestyle factors and genetic variations which predispose them to more extensive damage on acute and chronic trauma. As the discs between intervertebral bodies begin to degenerate, the whole cervical spine becomes less flexible leading to neck pain and stiffness in the neck and back. Those who practice yoga regularly and long-term are less likely to suffer from severe disc degeneration in the cervical spine compared to those who do not, most likely as result of improved flexibility and strength of the muscles supporting the spine (Jeng, 2010). The effect of long-term yoga practice on the lumbar spine was not considered significant by Jeng (2010), but there was some evidence of benefit in most of the study group.
Acute trauma, such as whiplash, or a contact sports injury, can trigger degenerative changes in the spine, including damage to the discs. The discs are also liable to trauma from twisting as their structure only allows for a certain degree of flexibility in either direction. This is beneficial for maintaining the limits of rotation in the spine, but can lead to damage to the fibers in the disc. The annulus is made up of multiple layers (lamellae) of collagen fibers arranged circumferentially along the edge of the disc. These lamella are oriented at a 30 degree angle to the horizontal axis of the disc and attach at the end plate around the nucleus and the ring apophysis on the outer edge of the disc. The arrangement of fibers in this fashion means that the rotation of the spine is resistant to tension past a certain point as some of the fibers are relaxed and some are stretched depending on the direction of rotation. Clearly, overstretching the spine to one side can cause damage to these fibers as they are stretched beyond their capacity. Trauma such as this can lead to instability in the spine, disc herniation, bulging of the discs, and degenerative disc disease of the cervical spine.
Windsor (2004) states that 36% of all spinal intervertebral disease is accounted for by degeneration of the cervical intervertebral discs (the leading cause is lumbar disc disease which accounts for 62%). By the mid-thirties the degeneration of the discs is usually well underway, with fifty year olds beginning to show degenerative changes in the spine. Gradual narrowing of the spinal canal (stenosis) can remain asymptomatic until myelopathy occurs in some patients. Acute trauma will exacerbate this degeneration. Cervical spondylosis and other degenerative conditions are usually interconnected and can cause problems such as pressure on the nerves exiting the spine leading to radiculopathy. Cervical disc disease with myelopathy is less common than disc degeneration without myelopathy, but both issues can cause neck pain and paraesthesia of the arms, including muscle weakness and problems of sensation. Occasionally the myelopathy extends to affect the legs, the bowel, and the bladder.
Next read about: Degenerative Disc Symptoms
Last Updated: 10/04/2010