A patient presents with severe neck and arm pain with numbness and tingling in all of the fingers (especially the third digit), and increased numbness in the central portion of the hand. The patient may complain of a Lhermitte sign, which is a generalized electrical shock-like sensation in the arms and/or back, precipitated by a jarring motion or during neck flexion.
The above history describes the probability of a combined cervical radiculopathy and myelopathy. In cervical radiculopathy, the nerve root most frequently affected is C7 (C6 disc) followed by C6 (C5 disc).2 In the above case, the C7 nerve root appeared to be principally involved, since the triceps muscle was weak and examination might have found a diminished triceps reflex. Paresthesia of the third finger was another sign.
It often is difficult to blame the location of pain and paresthesias on a single root, due to the overlap of innervation of adjacent roots, intradural connections between dorsal nerve rootlets and individual anatomic variability. Muscle innervation (muscle testing) is fairly constant and has greater specificity than either cutaneous sensation or reflex examinations.1 The complaint of numbness and/or tingling in all of the fingers may indicate a spinal cord origin, rather than a specific nerve root, and therefore may relate to a possible myelopathy. Passing over a bump and feeling the hands, and having problems with subtle complaints of buttoning the shirt or handling change, also should make you consider myelopathy.
Abduction of the arm above the head, which relieves the pain, and extending the head backward and rotated to the side of pain as the examiner applies pressure, causing an increase in pain (Spurling test), incriminates the nerve root. As myelopathy advances, there may be hyperreflexia, spasticity of muscles affecting gait, and pathological reflexes such as Hoffmann's and Babinski. In advanced cases, there also may be bladder dysfunction, such as feelings of urgency and intermittent incontinence. According to Houten and Errico,1 in cervical spondylotic myelopathy, "the hand intrinsic and triceps muscles are typically the earliest and most severely impaired" and "lower extremity weakness manifests in the proximal musculature, primarily affecting the iliopsoas." Regarding gait problems, spasticity, rather than weakness, is the underlying cause. Muscle weakness is not common in cervical myelopathy and becomes apparent in the later stages, when there is loss of anterior horn motor neurons.
In contrast to the lumbar spine, where herniation of the nucleus pulposus is common, the most common cause of cervical radiculopathy (70 percent to 75 percent of cases) is due to a combination of decreased disc height with degenerative changes of the uncovertebral joints, affecting the anterior portion of the nerve root and the posterior zygapophyseal joints compressing the nerve from behind.3 At present, there are no well-designed, randomized, controlled trials to guide whether to use conservative or surgical treatment. Persson, et al.,4 found that at the end of one year, there was no difference in the amount of pain, function, and mood in patients who had cervical radiculopathy and were treated by physiotherapy, immobilization with a hard collar, or surgery. Surgery is recommended when there are spinal cord signs and symptoms, persistence of pain for at least 6 to 12 weeks, or progressive motor deficit. There is a more favorable prognosis in radicular patients who have a soft disc herniation than from a foraminal stenosis from spondylosis or hard disc.
Cervical myelopathy is defined as symptomatic spinal cord compression, usually due to a decrease in the diameter of the spinal canal. It could be caused by a large central disc herniation. Myelopathy usually (but not always) has a slow, insidious onset and spinal cord compression does not have to produce neurologic symptoms. In long-term cervical spondylosis, the spinal cord has time to adapt to compression, resulting in gradually appearing neurologic changes; however, a trivial injury to this type of patient with acquired cervical stenosis may be the severe accident waiting to happen.
References
- Houten JK, Errico TJ. Cervical Spondylotic Myelopathy and Radiculopathy: Natural History and Clinical Presentation. In: Clark CR. The Cervical Spine, 4th edition. Philadelphia: Lippincott Williams & Wilkins, 2005.
- Radhakrishan D, Litchy WJ, O'Fallon WM, Kurland LT. Epidemiology of cervical radiculopathy: a population-based study from Rochester, Minnesota, 1976 through 1990. Brain 1994;117:325-535.
- Carette S, Phil M, Fehlings MG. Cervical radiculopathy. New England J Med 2005;353(4):392-399.
- Persson LC, Carlsson CA, Carlsson JY. Long-lasting cervical radicular pain managed with surgery, physiotherapy, or a cervical collar: a prospective, randomized study. Spine 1997:22:751-758.
Warren Hammer, MS, DC, DABCO
Norwalk, Connecticut
www.warrenhammer.com
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