Natural History of Cervical Degenerative Disorders

Abstract

Cervical spondylosis is a naturally occurring, age-related phenomenon that can be seen radiologically in 95% of males and 70% of females over the age of 70. It is characterized by degenerative changes affecting the vertebrae, intervertebral discs, facets, and associated ligaments. Starting in the third decade of life, there is a progressive loss of water content of the intervertebral disc that continues with age. This is due to a loss of glycosaminoglycan proteins, which attract molecules of water due to their high molecular weight and overall negative charge, located in the nucleus pulposus. As water molecules leave the nucleus pulposus, this results in a less elastic and more compressible disc that bulges into the spinal canal. At the same time, the vertebral bodies drift toward each other, and the ligamentum flavum and the facet joint capsule fold in dorsally. The combination of these events ultimately decreases the dimensions of the neural foramen and spinal canal. The approximation of the vertebral bodies leads to a reactive process that produces osteophytes around the margins of the disc and at the uncovertebral and facet joints. Radiculopathy in cervical spondylosis is the result of compression either by a hypertrophied facet joint or uncovertebral joints, disc protrusion, spondylotic spurring of the vertebral body, or any combination of these processes. Subacute radiculopathy occurs in patients with pre-existing cervical spondylosis, and these patients often develop symptoms which are polyradicular in nature.