Cervical Spondylotic Myelopathy: A Common Cause of Spinal Cord Dysfunction in Older Persons

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WILLIAM F. YOUNG, M.D., Temple University Hospital, Philadelphia, Pennsylvania

Cervical Spondylotic Myelopathy: A Common Cause of Spinal Cord Dysfunction in Older Persons part-2

FIGURE 3. Sagittal magnetic resonance imaging showing narrowing of the spinal canal as a result of anterior herniated discs/osteophytes (left) and posterior buckling of hypertrophied ligamentum flavum (right).Imaging and Diagnostic Studies

Magnetic resonance imaging (MRI) of the cervical spine is the procedure of choice during the initial screening process of patients with suspected CSM.¹⁵MRI is noninvasive and provides images of the spine and spinal cord in several planes (Figure 3). In addition to giving an assessment of the degree of spinal canal stenosis, an MRI can identify intrinsic spinal cord lesions that can also present with myelopathy (e.g., tumors). High signal changes seen in the spinal cord of patients with CSM may indicate myelomalacia or permanent spinal cord damage.

Computed tomography (CT) is complementary to MRI (Table 2). CT may give a more accurate assessment of the amount of canal compromise because it is superior to MRI in evaluating bone (osteophytes).

¹⁶ Myelography or the intrathecal injection of a contrast agent is used in conjunction with CT. Since the advent of MRI, the use of myelography has decreased; however, it still provides useful information in some instances for surgical planning. Plain radiographs alone are of little use as an initial diagnostic procedure.

Electromyography is rarely useful in most patients with CSM; however, it may help in the exclusion of specific syndromes such as peripheral neuropathy. Somatosensory evoked potentials (SSEPs) provide a more direct assessment of spinal cord function (e.g., dorsal column function) than electromyography.

¹⁷ However, SSEPs are nonspecific and therefore their use as a diagnostic tool is undetermined.

A characteristic physical finding of cervical spondylotic myelopathy is hyperreflexia.

Differential Diagnosis

The presence of myelopathy on neurologic examination is not unique to CSM. Therefore, it is important to exclude other diagnoses that present in a similar fashion. In one study, it was found that 14.3 percent of patients who underwent surgery for CSM were later found to have other diagnoses.¹⁸ This finding could be an explanation for the lack of neurologic improvement after surgery in some cases.

Because cervical spondylosis is a universal finding in the elderly population, it is important to correlate cervical spondylotic changes with sensorimotor abnormalities identified on examination.⁰If there is a lack of correlation, there may be a demyelinating process (e.g., multiple sclerosis). MRI is useful in this situation for identifying areas of demyelination in the spinal cord and cerebrum. In addition, a cerebrospinal fluid examination (e.g., oligoclonal bands) and visual evoked esponses are important diagnostic adjuncts.

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