Cervical radiculopathy: nonoperative management of neck pain and radicular symptoms.
From: Am Fam Physician. 2010 Jan 1;81(1):33-40.
A variety of conditions can lead to nerve root compression in the cervical spine. Each motion segment in the subaxial spine (C3 through C7) consists of five articulations, including the intervertebral disc, two facet joints, and two neurocentral (uncovertebral) joints. Bounded by these elements, the nerve roots exit laterally.
Unlike the lumbar spine, the cervical spine has cervical nerve roots that exit above the level of the corresponding pedicle. For instance, the C5 nerve root exits at the C4-C5 disc space, and a C4-C5 disc herniation typically leads to C5 radiculopathy. There are seven cervical vertebrae and eight cervical nerve roots. In the lumbar spine, the nerve exits below the corresponding pedicle. Therefore, an analogous lumbar disc herniation (L4-L5) would compress the traversing nerve root (L5), not the exiting root (L4). Whether in the cervical spine or the lumbar spine, the nerve impingement typically occurs in the nerve numerically corresponding to the lower of the two vertebral levels.
The exiting nerve root can be compressed by herniated disc material (soft disc herniation) or through encroachment by surrounding degenerative or hypertrophic bony elements (hard disc pathology). In either case, a combination of factors, such as inflammatory mediators (e.g., substance P), changes in vascular response, and intra-neural edema, contribute to the development of radicular pain.
Chronic neck pain associated with spondylosis is typically bilateral, whereas neck pain associated with radiculopathy is more often unilateral. Pain radiation varies depending on the involved nerve root, although some distributional overlap may exist. Absence of radiating extremity pain does not preclude nerve root compression. At times, pain may be isolated to the shoulder girdle. Similarly, sensory or motor dysfunction may be present without significant pain. Symptoms are often exacerbated by extension and rotation of the neck, which decreases the size of the neural foramen. Holding the arm above the head (shoulder abduction sign) decompresses the exiting nerve root.
