EVP
10.12.2005, 00:36
Cervical Radiculopathy
Simon Carette, M.D., M.Phil., and Michael G. Fehlings, M.D., Ph.D.
[Ссылки могут видеть только зарегистрированные и активированные пользователи]
A 37-year-old woman presents with a two-week history of severe neck pain radiating to her left shoulder girdle and extending to the arm, forearm, and dorsum of the hand. She reports having had no fever, weight loss, leg weakness, or urinary or bowel dysfunction. Physical examination reveals weakness of her left triceps, finger extensors, and wrist flexors, as well as hypoesthesia of the third digit and a diminished triceps reflex. How should her case be managed?
The Clinical Problem
Cervical radiculopathy is a neurologic condition characterized by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. It usually presents with pain in the neck and one arm, with a combination of sensory loss, loss of motor function, or reflex changes in the affected nerve-root distribution.1
Epidemiology
Population-based data from Rochester, Minnesota, indicate that cervical radiculopathy has an annual incidence rate of 107.3 per 100,000 for men and 63.5 per 100,000 for women, with a peak at 50 to 54 years of age.2 A history of physical exertion or trauma preceded the onset of symptoms in only 15 percent of cases. A study from Sicily reported a prevalence of 3.5 cases per 1000 population.3
Data on the natural history of cervical radiculopathy are limited.2,4,5,6 In the population-based study from Rochester, Minnesota, 26 percent of 561 patients with cervical radiculopathy underwent surgery within three months of the diagnosis (typically for the combination of radicular pain, sensory loss, and muscle weakness), whereas the remainder were treated medically.2 Recurrence, defined as the reappearance of symptoms of radiculopathy after a symptom-free interval of at least 6 months, occurred in 32 percent of patients during a median follow-up of 4.9 years. At the last follow-up, 90 percent of the patients had normal findings or were only mildly incapacitated owing to cervical radiculopathy.
Causes and Pathophysiological Features
The most common cause of cervical radiculopathy (in 70 to 75 percent of cases) is foraminal encroachment of the spinal nerve due to a combination of factors, including decreased disc height and degenerative changes of the uncovertebral joints anteriorly and zygapophyseal joints posteriorly (i.e., cervical spondylosis) (Figure 1). In contrast to disorders of the lumbar spine, herniation of the nucleus pulposus is responsible for only 20 to 25 percent of cases.2 Other causes, including tumors of the spine and spinal infections, are infrequent.7
The mechanisms underlying radicular pain are poorly understood. Nerve-root compression by itself does not always lead to pain unless the dorsal-root ganglion is also compressed.8,9 Hypoxia of the nerve root and dorsal ganglion can aggravate the effect of compression.10 Evidence from the past decade indicates that inflammatory mediators — including matrix metalloproteinases, prostaglandin E2, interleukin-6, and nitric oxide — are released by herniated cervical intervertebral disks.11,12,13 These observations provide a rationale for treatment with antiinflammatory agents.14 In patients with disk herniation, the resolution of symptoms with nonsurgical management correlates with attenuation of the herniation on imaging studies.
Strategies and Evidence
Clinical Diagnosis
There are no universally accepted criteria for the diagnosis of cervical radiculopathy.19 In most cases, the patient's history and physical examination are sufficient to make the diagnosis.20 Typically, patients present with severe neck and arm pain. Although the sensory symptoms (including burning, tingling, or both) typically follow a dermatomal distribution, the pain is more commonly referred in a myotomal pattern.2,21 For example, radicular pain from C7 is usually perceived deeply through the shoulder girdle with extension to the arm and forearm, whereas numbness and paresthesias are more commonly restricted to the central portion of the hand, the third digit, and occasionally the forearm. Subjective weakness of the arm or hand is reported less frequently. Holding the affected arm on top of the head22 or moving the head to look down and away from the symptomatic side often improves the pain, whereas rotation of the head or bending it toward the symptomatic side increases the pain.23
Guidelines developed by the Agency for Health Care Policy and Research for the assessment of low back pain may be applied to the patient with neck pain and radiculopathy.24 The presence of "red flags" in the patient's history (including fever, chills, unexplained weight loss, unremitting night pain, previous cancer, immunosuppression, or intravenous drug use) should alert clinicians to the possibility of more serious disease, such as tumor or infection. Clinicians should also inquire about symptoms of myelopathy. These may occasionally be subtle (e.g., diffuse hand numbness and clumsiness, which are often attributed to peripheral neuropathy or carpal tunnel syndrome; difficulty with balance; and sphincter disturbances presenting initially as urinary urgency or frequency rather than as retention or incontinence).
Findings on physical examination vary depending on the level of radiculopathy and on whether there is myelopathy (Table 1 and Table 2). In most series, the nerve root that is most frequently affected is the C7, followed by the C6.2 Many provocative tests have been proposed for the diagnosis of cervical radiculopathy, but the reliability and diagnostic accuracy of these tests are poor.19,25
Several conditions can mimic cervical radiculopathy and should be ruled out by history taking and physical examination, occasionally supplemented by imaging, electrophysiological studies, or both.
Laboratory Studies
Laboratory studies are of limited value and are not recommended. The erythrocyte sedimentation rate and C-reactive protein levels are elevated in many patients with spinal infection or cancer, but these tests are not sufficiently sensitive or specific to guide further evaluation.
Imaging
Conventional radiographs of the cervical spine are often obtained, but their usefulness is limited.31 This is due to the low sensitivity of radiography for the detection of tumors or infections, as well as its inability to detect disk herniation and the limited value of the finding of cervical intervertebral narrowing in predicting nerve-root or cord compression.32
Magnetic resonance imaging (MRI) is the approach of choice when imaging is pursued in patients with cervical radiculopathy (Figure 1), 33 but there are currently no clear guidelines regarding when such imaging is warranted. Reasonable indications include the presence of symptoms or signs of myelopathy, red flags suggestive of tumor or infection, or the presence of progressive neurologic deficits. For most other patients, it is appropriate to limit the use of MRI to those who remain symptomatic after four to six weeks of nonsurgical treatment, particularly given the high frequency of abnormalities detected in asymptomatic adults, including disk herniation or bulging (57 percent of cases), spinal cord impingement (26 percent), and cord compression (7 percent).34
Computed tomography (CT) alone is of limited value in assessing cervical radiculopathy,35 but it can be useful in distinguishing the extent of bony spurs, foraminal encroachment, or the presence of ossification of the posterior longitudinal ligament. The combination of CT with the intrathecal administration of contrast material (CT myelography) provides accuracy similar to36 and possibly superior to37 that of MRI, but its invasive nature makes MRI preferable in most cases. Technetium and gallium bone scans are very seldom indicated, except in rare cases in which cancer or infection is suspected in multiple sites and MRI cannot be readily performed or is impractical.
Electrodiagnostic Studies
Needle electromyography and nerve-conduction studies can be helpful when the patient's history and physical examination are inadequate to distinguish cervical radiculopathy from other neurologic causes of neck and arm pain. Typically, abnormal insertional activity, including positive sharp-wave potentials and fibrillation potentials, is present in the limb muscles of the involved myotome within three weeks of the onset of nerve compression.38 Examination of the paraspinal muscles increases the sensitivity of the test, since insertional activity can be seen as early as 10 days after the nerve injury. In addition, the presence of abnormal findings in paraspinal muscles differentiates cervical radiculopathy from brachial plexopathy.
Simon Carette, M.D., M.Phil., and Michael G. Fehlings, M.D., Ph.D.
[Ссылки могут видеть только зарегистрированные и активированные пользователи]
A 37-year-old woman presents with a two-week history of severe neck pain radiating to her left shoulder girdle and extending to the arm, forearm, and dorsum of the hand. She reports having had no fever, weight loss, leg weakness, or urinary or bowel dysfunction. Physical examination reveals weakness of her left triceps, finger extensors, and wrist flexors, as well as hypoesthesia of the third digit and a diminished triceps reflex. How should her case be managed?
The Clinical Problem
Cervical radiculopathy is a neurologic condition characterized by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. It usually presents with pain in the neck and one arm, with a combination of sensory loss, loss of motor function, or reflex changes in the affected nerve-root distribution.1
Epidemiology
Population-based data from Rochester, Minnesota, indicate that cervical radiculopathy has an annual incidence rate of 107.3 per 100,000 for men and 63.5 per 100,000 for women, with a peak at 50 to 54 years of age.2 A history of physical exertion or trauma preceded the onset of symptoms in only 15 percent of cases. A study from Sicily reported a prevalence of 3.5 cases per 1000 population.3
Data on the natural history of cervical radiculopathy are limited.2,4,5,6 In the population-based study from Rochester, Minnesota, 26 percent of 561 patients with cervical radiculopathy underwent surgery within three months of the diagnosis (typically for the combination of radicular pain, sensory loss, and muscle weakness), whereas the remainder were treated medically.2 Recurrence, defined as the reappearance of symptoms of radiculopathy after a symptom-free interval of at least 6 months, occurred in 32 percent of patients during a median follow-up of 4.9 years. At the last follow-up, 90 percent of the patients had normal findings or were only mildly incapacitated owing to cervical radiculopathy.
Causes and Pathophysiological Features
The most common cause of cervical radiculopathy (in 70 to 75 percent of cases) is foraminal encroachment of the spinal nerve due to a combination of factors, including decreased disc height and degenerative changes of the uncovertebral joints anteriorly and zygapophyseal joints posteriorly (i.e., cervical spondylosis) (Figure 1). In contrast to disorders of the lumbar spine, herniation of the nucleus pulposus is responsible for only 20 to 25 percent of cases.2 Other causes, including tumors of the spine and spinal infections, are infrequent.7
The mechanisms underlying radicular pain are poorly understood. Nerve-root compression by itself does not always lead to pain unless the dorsal-root ganglion is also compressed.8,9 Hypoxia of the nerve root and dorsal ganglion can aggravate the effect of compression.10 Evidence from the past decade indicates that inflammatory mediators — including matrix metalloproteinases, prostaglandin E2, interleukin-6, and nitric oxide — are released by herniated cervical intervertebral disks.11,12,13 These observations provide a rationale for treatment with antiinflammatory agents.14 In patients with disk herniation, the resolution of symptoms with nonsurgical management correlates with attenuation of the herniation on imaging studies.
Strategies and Evidence
Clinical Diagnosis
There are no universally accepted criteria for the diagnosis of cervical radiculopathy.19 In most cases, the patient's history and physical examination are sufficient to make the diagnosis.20 Typically, patients present with severe neck and arm pain. Although the sensory symptoms (including burning, tingling, or both) typically follow a dermatomal distribution, the pain is more commonly referred in a myotomal pattern.2,21 For example, radicular pain from C7 is usually perceived deeply through the shoulder girdle with extension to the arm and forearm, whereas numbness and paresthesias are more commonly restricted to the central portion of the hand, the third digit, and occasionally the forearm. Subjective weakness of the arm or hand is reported less frequently. Holding the affected arm on top of the head22 or moving the head to look down and away from the symptomatic side often improves the pain, whereas rotation of the head or bending it toward the symptomatic side increases the pain.23
Guidelines developed by the Agency for Health Care Policy and Research for the assessment of low back pain may be applied to the patient with neck pain and radiculopathy.24 The presence of "red flags" in the patient's history (including fever, chills, unexplained weight loss, unremitting night pain, previous cancer, immunosuppression, or intravenous drug use) should alert clinicians to the possibility of more serious disease, such as tumor or infection. Clinicians should also inquire about symptoms of myelopathy. These may occasionally be subtle (e.g., diffuse hand numbness and clumsiness, which are often attributed to peripheral neuropathy or carpal tunnel syndrome; difficulty with balance; and sphincter disturbances presenting initially as urinary urgency or frequency rather than as retention or incontinence).
Findings on physical examination vary depending on the level of radiculopathy and on whether there is myelopathy (Table 1 and Table 2). In most series, the nerve root that is most frequently affected is the C7, followed by the C6.2 Many provocative tests have been proposed for the diagnosis of cervical radiculopathy, but the reliability and diagnostic accuracy of these tests are poor.19,25
Several conditions can mimic cervical radiculopathy and should be ruled out by history taking and physical examination, occasionally supplemented by imaging, electrophysiological studies, or both.
Laboratory Studies
Laboratory studies are of limited value and are not recommended. The erythrocyte sedimentation rate and C-reactive protein levels are elevated in many patients with spinal infection or cancer, but these tests are not sufficiently sensitive or specific to guide further evaluation.
Imaging
Conventional radiographs of the cervical spine are often obtained, but their usefulness is limited.31 This is due to the low sensitivity of radiography for the detection of tumors or infections, as well as its inability to detect disk herniation and the limited value of the finding of cervical intervertebral narrowing in predicting nerve-root or cord compression.32
Magnetic resonance imaging (MRI) is the approach of choice when imaging is pursued in patients with cervical radiculopathy (Figure 1), 33 but there are currently no clear guidelines regarding when such imaging is warranted. Reasonable indications include the presence of symptoms or signs of myelopathy, red flags suggestive of tumor or infection, or the presence of progressive neurologic deficits. For most other patients, it is appropriate to limit the use of MRI to those who remain symptomatic after four to six weeks of nonsurgical treatment, particularly given the high frequency of abnormalities detected in asymptomatic adults, including disk herniation or bulging (57 percent of cases), spinal cord impingement (26 percent), and cord compression (7 percent).34
Computed tomography (CT) alone is of limited value in assessing cervical radiculopathy,35 but it can be useful in distinguishing the extent of bony spurs, foraminal encroachment, or the presence of ossification of the posterior longitudinal ligament. The combination of CT with the intrathecal administration of contrast material (CT myelography) provides accuracy similar to36 and possibly superior to37 that of MRI, but its invasive nature makes MRI preferable in most cases. Technetium and gallium bone scans are very seldom indicated, except in rare cases in which cancer or infection is suspected in multiple sites and MRI cannot be readily performed or is impractical.
Electrodiagnostic Studies
Needle electromyography and nerve-conduction studies can be helpful when the patient's history and physical examination are inadequate to distinguish cervical radiculopathy from other neurologic causes of neck and arm pain. Typically, abnormal insertional activity, including positive sharp-wave potentials and fibrillation potentials, is present in the limb muscles of the involved myotome within three weeks of the onset of nerve compression.38 Examination of the paraspinal muscles increases the sensitivity of the test, since insertional activity can be seen as early as 10 days after the nerve injury. In addition, the presence of abnormal findings in paraspinal muscles differentiates cervical radiculopathy from brachial plexopathy.