Degenerative Diseases of the Spine: Lecture on the Cervical Spine (Clinical Presentation)

The cervical spine is particularly susceptible to the degenerative process, in part because of its large range of motion and the five–joint complex making up each spinal motion unit.

These five joints are:

• the intervertebral disc,
• the two zygoapophyseal joints, and
• the two uncovertebral joints.

The degenerative process may begin in any of these joints but with time will cause secondary changes in the others. For example, the intervertebral disc may be primarily affected. As the disc narrows, the normal kinematics of that segment is altered, and the other four joints are subjected to abnormal forces leading to degenerative arthritis.

Neck pain as a result of spondylosis is common. The pain usually radiates into the shoulder blade or arm. Patients may have an arm complaint, not as the result of nerve root compression. Dysphagia (rarely) can result from large anterior osteophytes.

Physical examination may show a spasm of the paravertebral, trapezium, or sternomastoid muscles. This may be secondary to pain. In association with the degenerative process, this can result in a decreased range of motion. Movement of the cervical spine may precipitate or exacerbate symptoms.

A thorough neurologic examination must always be done to rule out a deficit. A shoulder examination should also be done to ensure that the symptoms are indeed originating from the neck.

Diagnostic Evaluation: X–RAY

Plain radiographs of the cervical spine may show narrowing of the intervertebral disc space height, anterior osteophytes, arthrosis of the facet joints, and osteophytes from the uncovertebral joints (see figures below). The most commonly affected level is C5–C6, followed by the C6–C7 level.

Diagnostic Evaluation: Computed Tomography

Computed tomography (CT) provides good demonstration of the bony changes associated with degenerative spondylosis. Osteophytes can be evaluated both on axial and sagittal cuts. However, CT does not allow optimal evaluation of disc pathology. It can be used to show disc herniations, but these may not always be present, even with advanced degenerative changes.

Diagnostic Evaluation: Magnetic Resonance Imaging

Magnetic resonance imaging (MRI) is a powerful tool in the assessment of patients with symptomatic cervical spondylosis. Decreased signal intensity on T2–weighted images results from disc desiccation. T1–weighted images can show osteophytes and joint arthrosis. Because MRI is a sensitive imaging modality, pathology may be demonstrable in more than 40% of asymptomatic people over age 40 (see figure).

MRI remains a morphometric test, and the clinician must correlate MRI findings with symptoms.

Diagnostic Evaluation: Discography

As in the lumbar and thoracic spine, cervical discography (see figure) remains controversial. Although the discogram may add to the clinician's knowledge, it should not be used by itself to predicate treatment.

Diagnostic Evaluation: Facet Blocks

Facet blocks in the cervical spine are subject to the same criticisms as facet blocks used elsewhere. There is little scientific documentation to validate their use. Repeating the test and comparing results at different levels probably gives much more useful information than carrying out facet blocks at one or more levels at one point in time.

Treatment: Nonoperative

Nonoperative treatment of cervical degenerative disease provides good to excellent results in over 75% of patients. A multidisciplinary approach includes:

• immobilization (can be achieved using a collar or braces; most beneficial during acute exacerbations of pain by reducing motion at the symptomatic levels),
• physical therapy, (can be useful in decreasing the secondary muscle spasm that can contribute to symptoms; this is where heat, electrical stimulation, and exercise have their maximum benefit), and
• medications (include analgesics, nonsteroidal anti–inflammatories, and muscle relaxants, patients must be informed of possible complications and side effects).
  

Patients should be reassured that nonoperative treatment can provide good long–term results.

Treatment: Operative

The surgical procedure proposed for these patients is usually fusion. In almost all instances, the preferred approach is an anterior interbody fusion. Using the anterior approach, a complete discectomy can be done, and with careful sculpting of the graft, normal intervertebral disc space height and normal lordosis can be restored. An Anterior metal plate may be utilized to help restore stability.

Until diagnostic testing improves to the point where we can show irrefutably that a specific cervical spinal motion unit is giving rise to symptoms, surgery for neck pain without neurologic involvement should be discouraged.