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13 Articles in Volume 11, Issue #7
Fibromyalgia: Practical Approaches To Diagnosis and Treatment
Juvenile Fibromyalgia: Diagnostic Challenges and Treatment Options
Aqua Therapy Helpful in Treatment Of Systemic Lupus Erythematosus
Axial Neck Pain, Radiculopathy, and Myelopathy: Recognition and Treatment
Early Treatment of TMD May Prevent Chronic Pain and Disability
Identifying Psychological Factors That Influence Surgical Outcomes
Managing Morton’s Entrapment
Premedicated Mask May Hold Promise for Migraine Patients
Mother With Low Back Pain
The Hip Replacement Patient
Evidence-based Medicine: Losing the Patient’s Voice?
What Is Going Wrong With Research?
Risk for Sedation and Car Accidents

Axial Neck Pain, Radiculopathy, and Myelopathy: Recognition and Treatment

Neck pain, radiculopathy, and myelopathy are common presentations of cervical pathology across populations and age groups. Many people experience neck pain at some point in their lives, and nearly everyone has cervical spondylosis associated with aging, although for most it does not produce a limitation in activity. A typical 12-month prevalence rate of neck pain for working adults is 30% to 50%; for children and adolescents, the rate is 20% to 40%.1 Limitation of activity related to this pain has a 12-month prevalence of 2% to 11%.1 To simplify the broad presentation of cervical pathology and best assign its treatment, it is helpful to divide patient findings into axial neck pain, radiculopathy, and myelopathy.

Axial Neck Pain
Axial neck pain can arise from a variety of conditions but occurs primarily from muscular or ligamentous factors and joint pain. The etiology of neck pain arising from a muscular origin is not entirely clear, but it has been shown that in patients with primary muscular pain, there is a lower level of high-energy phosphates in the affected muscle than in normal muscle tissue.2 Whether this is the cause or effect of the pain has yet to be determined. Neck pain also can arise from other joint pain and be referred from primary pain in the temperomandibular joint or craniovertebral junction or from the facet joints in the spine itself.3 Because of the widespread prevalence of facet joint degeneration and lack of consistent presentation with axial neck pain, it is not recommended to assign the presence of pain solely to degenerative changes in the facet joints.3

Diagnosis of Axial Neck Pain
Patients with axial neck pain typically present with pain or soreness in the posterior neck muscles, with frequent radiation to the occiput or shoulder regions that does not usually follow a dermatomal distribution.3 There often is stiffness of the neck, and headaches are common as well. As a general rule, pain in the posterior neck that is exacerbated by neck extension, especially with rotation to the affected side, stems from a discogenic source. Pain that is aggravated by flexion is typically myofascial in origin.3 Because of the frequency of referred pain causing axial neck pain, it is important to rule out other etiologies that are not directly related to the neck, such as temporomandibular joint pain, infection, or neoplasm, to best direct treatment (Table 1).

Treatment of Axial Neck Pain
The simplest treatments for axial neck pain stem from lifestyle and activity modifications (Figure 1). Smoking cessation and avoidance of activities that place strain on the neck (excessive extension or flexion) are early treatment options. There is some evidence for the effectiveness of active physical therapy combined with patient education emphasizing a quick return to normal function in helping to ease axial neck pain.1 Scientific data on the benefits of other nonoperative treatment options, including acupuncture, educational pamphlets, “neck school,” and use of collars, are lacking, but these modalities are often prescribed.1,4 The use of interlaminar epidural steroid injections has been shown to be extremely effective, with short-term relief in as many as 96% of patients and 1-year improvement between 68% and 79%.5 Transforaminal epidural steroid injections are slightly less efficacious, though they still produce positive short-term and long-term relief in more than 60% of patients.5 A medial branch block, which functions by anesthetizing the innervation of facet joints, is often administered if the pain is suspected to originate from these joints.6 Improvement of symptoms after medial branch block is also indicative that radiofrequency ablation will likely be effective.7 This technique is performed by percutaneously placing an electrode against the nerves supplying the painful joint. These electrodes are then heated to 80°C to produce lesions in the nerves and prevent pain transmission. Radiofrequency ablation was shown to be very effective by Lord et al, with a median return of pain at 263 days for patients receiving treatment and 8 days for patients in the control group.8

Because most cases of axial neck pain are self-limited or effectively alleviated with nonsurgical treatment, operative interventions are a last resort and are indicated only after an extended period of time without improvement from nonoperative treatment. There are also contraindications for surgery to treat axial neck pain, including psychosocial problems such as anxiety and depression6 and pain stemming from multiple spinal levels. This has led to the recommendation that computed tomography (CT) examination, physical evaluation, psychological testing, and other diagnostic testing be performed before operative interventions are considered.9

Surgical options for the treatment of axial neck pain include cervical fusion and cervical arthroplasty. In anterior cervical discectomy and fusion, the cervical disc is removed from an anterior approach, replaced with a bone graft, and the adjacent vertebrae are fused. If osteophytes are present, they may be removed as well. Anterior cervical plates may be used to augment fusion, provide stability, and prevent bone graft kick-out. Arthroplasty is similar to anterior discectomy except that there is no fusion of the spine, but rather implantation of a disc replacement. The advantages to this technique are maintenance of flexibility and range of motion after surgery and a theoretical benefit of less adjacent-level degeneration. Several different cervical disc arthroplasty devices are available in the United States, and specific use is driven by both patient and surgeon preference. Both of these techniques show excellent short-term and long-term improvement in severe neck pain12,13 and headaches,14 with arthroplasty producing similar or better results in multiple studies and no evidence of long-term spinal cord trauma because of the additional mobility conferred by arthroplasty.12-15

Cervical Radiculopathy
Radiculopathy is the result of compression of a spinal nerve root, which causes pain and numbness in a dermatomal distribution (Figure 2), muscle weakness, and impaired deep tendon reflexes.16-18 Cervical radiculopathy has an estimated prevalence of 3.5 cases per 1,000,19 with the highest rate of incidence in the sixth decade of life.20 Symptoms typically manifest as pain traveling down the neck and shoulder into the arm of the patient. The pain can vary substantially, ranging from sharp localized pain to dull general pain in the neck and upper extremity. In general, the presence of muscle weakness and loss of sensation correspond with increased severity. This is due to the relative number of neurons that must be damaged to produce each set of symptoms, with pain requiring the least neuronal damage and total loss of sensation requiring the most.21

There are several pathologic processes that can give rise to cervical radiculopathy, including disc herniation, cervical spondylosis, extraspinal compressive radiculopathies, and noncompressive radiculopathies. Disc herniation is typically related to aging, because the nucleus pulposus loses hydration and the annulus weakens and becomes more likely to herniate. However, herniation also can occur after trauma. This herniated material most frequently expands into the lateral side of the spinal canal, which causes direct pressure on the nerve root.22 Cervical spondylosis results in radiculopathy by compressing the nerve via osteophytes or reducing the distance between pedicles via decreased intervertebral disc height.22 The majority (70%) of degenerative cervical radiculopathies are due to spondylosis.23

Extraspinal compressive forces that can cause radiculopathy include neurogenic thoracic outlet syndrome and postmedian sternotomy brachial plexopathy. Neurogenic thoracic outlet syndrome occurs when a congenital band of tissue stretches from the first rib to the transverse process of C7, in turn placing pressure on nerve fibers T1 and C8.23 Postmedian sternotomy brachial plexopathy can occur after surgery in the chest and is due to an occult fracture of the first rib, which then places pressure on nerve fiber C8.23 Cervical radiculopathy also can be due to infection, inflammatory lesions, or neoplasm that either directly compress the nerve root, cause its inflammation, or disrupt its blood supply (Table 2).23

Diagnosis of Cervical Radiculopathy
There are several physical examination tests that can be very helpful in the diagnosis of cervical radiculopathy. The first is the Spurling test, which involves tilting the patient’s head to the affected side to aggravate the symptoms of the radiculopathy.24 The physician then applies pressure to the top of the head and observes if the symptoms are intensified. Alleviation of the symptoms is achieved by tilting the head to the opposite side. If the application of pressure during the test produces radicular pain traveling into the ipsilateral arm, it is considered a positive test.21 A recent study has shown that when done properly, the Spurling test has 92% sensitivity and 95% specificity, making it the standard for physical evaluation of cervical radiculopathy.25

Another test pioneered by Spurling, called the shoulder abduction test, involves raising the arm above the head with concurrent relief of radicular symptoms. This test lacks the sensitivity and specificity required to be a strong diagnostic indicator, but it has been shown to be an excellent predictor of surgical outcomes21 and can be incorporated into nonoperative treatment regimens for its therapeutic value. The final physical test that may be beneficial for diagnosis is the Hoffman sign, which involves flicking the fingernail of the third digit from posterior to anterior while supporting the patient’s hand. Flexion of ipsilateral digits confirms a positive test, which indicates neuronal damage (although not necessarily radiculopathy). The reliability of the Hoffman sign is questionable,26 but one study did find sensitivity of 58% and specificity of 78% for the test.27

Diagnosis of radiculopathy also can be aided by electrodiagnostic testing. These tests should be interpreted in conjunction with the physical examination findings, because almost half of patients with abnormal electrodiagnostic tests have received normal physical examinations.28 Electrodiagnosis is a class of tests that includes needle electrode examination and nerve conduction studies, which are important in the diagnosis of radiculopathy.18 Needle electrode examination is performed by inserting a needle electrode into the muscle tissue and observing the electrical activity within the muscle. The presence of abnormalities in two or more muscles innervated by the same root but different peripheral nerves is indicative of radiculopathy.28 Because this procedure can be quite painful for the patient, minimizing testing to the fewest possible sites is optimal. It has been determined that screening six different muscles, including the cervical paraspinal muscles, with needle electrode examination will identify 94% to 99% of cervical radiculopathies.28

Nerve conduction studies do not directly help in diagnosing radiculopathy but can exclude other, similar conditions. They are performed by stimulating a portion of a peripheral nerve, either sensory or motor, and detecting the latency and amplitude of the impulse once it reaches the recording electrode. Both motor and sensory nerve conduction studies are used to rule out other conditions similar to radiculopathy, such as peripheral neuropathy and entrapment mononeuropathy.29 Motor nerve conduction studies also can produce results diagnostic of axon loss in radiculopathy.28

Imaging studies are perhaps the most important facet in the diagnosis of cervical radiculopathy. Plain radiographs are routinely used as the first imaging study when investigating spine pain, but many articles have been written refuting the usefulness of plain radiographs in making relevant diagnoses because of their inability to visualize soft tissue or fine detail of bony tissue.30 To better differentiate these types of tissues, magnetic resonance imaging (MRI) is used. It is much better for visualizing the soft tissue of the intervertebral discs and spinal nerves and thus determining if they are being compressed. CT scan is another imaging test that is very useful in diagnosing radiculopathy because of its ability to detect osteophytes and stenosis of vertebral foramina. CT myelography is useful in situations where MRI is contraindicated, such as in patients with pacemakers or metallic instrumentation.30 CT myelography improves imaging of soft tissues and foraminal stenosis compared with regular CT scans.

Treatment of Cervical Radiculopathy
Spontaneous recovery has been reported in cases of cervical radiculopathy. It is more likely to occur in the case of disc herniation, because most cervical disc herniations have been shown to improve with time.16 At the onset of symptoms, most patients begin treatment with analgesics, such as nonsteroidal anti-inflammatory agents, which are effective at treating pain in the setting of acute radiculopathy.32 At this point, cessation of aggravating activities is very important (Figure 3). Pharmaceutical treatments such as muscle relaxers, narcotic analgesics, and corticosteroids are frequently prescribed and show good short-term effects on pain. Translaminar or transforaminal epidural corticosteroid injections also have shown long-term success rates of 40% to 70%33,34 by reducing inflammation of the spinal nerve and its roots.35 Potential complications of these injections can be reduced substantially by using fluoroscopy during the injection process.36 Physical therapy with range of motion exercises, aerobic conditioning, and resistive exercises has been shown to be beneficial in treating cervical radiculopathy.37 Spinal manipulation and mobilization treatments have limited evidence of efficacy and generally are not recommended.38 As a whole, nonoperative treatments have been shown to completely resolve symptoms in more than 40% of patients.39

Operative treatments are generally considered for radiculopathy when nonoperative treatments have failed to produce noticeable improvements after 3 months.31 Three operative treatments are recommended for cervical radiculopathy: anterior cervical discectomy and fusion, arthroplasty, and posterior foraminotomy. Lateral disc herniations can be approached using either anterior or posterior surgical operations, but in patients with central or bilateral disc lesions, an anterior approach is preferred.31 Anterior discectomy and fusion is the most commonly performed procedure to correct radiculopathy (see case 1). The procedure typically provides rapid relief of arm and neck pain, weakness, and loss of sensation that is maintained for a minimum of 12 months with high rates of success, but rates of recurrence have been shown to reach levels as high as 30%.40 Smoking reduces the rate of successful surgical outcomes, and patients should be strongly encouraged to stop smoking before and after surgery.41 Arthroplasty has produced results similar to or better than those with anterior discectomy and fusion in multiple studies11-15 and maintains a greater degree of spinal mobility in the patient. Posterior foraminotomy is performed by removing bone from the lamina and part of the facet joint to decompress the exiting nerve root.10 The success rates of posterior foraminotomy are excellent, with 96% resolution of radicular symptoms.10

Cervical Myelopathy
Cervical myelopathy arises from degenerative changes in the cervical spine that cause spinal cord compression (Table 3). Patients suffering from cervical myelopathy frequently present with weakness, loss of balance, decreased fine motor skills, spasticity, loss of sensation in the extremities, and concurrent radiculopathy. A very common feature of myelopathy is an increase in symptoms while extending the neck. This occurs because the spinal cord must shorten in response to neck extension, thus exacerbating the compressive forces.3,42 Paresthesias also are a common finding and typically occur in a global, nondermatomal distribution.42 Patients frequently present with hyperreflexia of deep tendons and loss of pinprick and vibrational sensation.

Another characteristic finding of cervical myelopathy is “myelopathy hand,” which is a term for a broad range of symptoms involving the hand. These include an inability to maintain extension and adduction of the fingers for more than 30 seconds (finger escape), loss of dexterity, weakness, and failure to rapidly form and release a fist repeatedly.31 These symptoms have been attributed to anterior horn necrosis43 thought to arise from compressive ischemia of the spinal cord vasculature.44

The rates of incidence and prevalence are unknown,43 but a congenitally narrow spinal canal can predispose patients to developing myelopathy.45 The degeneration can include intervertebral discs, joints, and/or ligaments and typically includes multiple spinal levels.45 Multiple causes of myelopathic damage can occur, including a decrease in the diameter of the canal, changes in the spinal cord resulting in its own compression, and damage to nearby ligaments resulting in cord compression. The most common sources of spinal canal stenosis are disc degeneration and bulging, vertebral subluxation, and osteophyte formation.45 The ligamentum flavum also can thicken or buckle in response to a decrease in disc height, further narrowing the spinal canal.42 Ossification of the posterior longitudinal ligament also can place pressure on the spinal cord and produce myelopathy.42

Diagnosis of Cervical Myelopathy
Diagnosis of cervical myelopathy typically begins with recognition of the typical pattern of myelopathic symptoms, including changes in gait, weakness, spasticity, paresthesias, and hyperreflexia. These symptoms can be revealed on physical exam, vibratory testing, pinprick examination, and reflex testing, as well as the patient’s personal account of symptoms. The European Myelopathy Score, an assessment tool that evaluates the severity of these symptoms, can be given to determine the severity of myelopathic damage. Higher scores correspond with lower severity of symptoms, with progressively worse severity ranked into classes I to III.43 If indicated, patients frequently undergo electrodiagnostic examination, which includes testing such as nerve conduction, electromyography, and electroneurography.46 The diagnostic ability of these tests is not ideal, however, and should be supplemented with radiographic testing.

Plain radiographs are useful in detecting large changes to the spinal canal, particularly those related to bony structures, including degenerative vertebral subluxations or ossification of the posterior longitudinal ligament. CT scans also can evaluate these findings and are better at detecting osteophytes and other small bony changes. MRI is the most useful method for diagnosis of the degree of spinal canal stenosis and evaluation of spinal cord myelomalacia. It is the best technique for detecting ligamentum flavum buckling and disc deformities.

Treatment of Cervical Myelopathy
Cervical myelopathy should be treated according to the severity of symptoms but is generally remedied only through surgical means (Figure 4). Activities that exacerbate symptoms, such as prolonged extension and flexion and manipulation therapies, are strongly discouraged if myelopathy is suspected. High-risk activities such as contact sports are essentially forbidden. Noninvasive therapies, including analgesics, cervical collars, and bed rest, are generally ineffective at stopping or reversing the progression of myelopathic symptoms31 but are a reasonable alternative for patients refusing surgery. The effectiveness of nonoperative treatments is unclear, because some studies have shown them to be as effective as surgery in patients with mild myelopathy,47 but others have shown surgery to be more efficacious,48 particularly in patients with severe or progressing myelopathy.31,45,49 In general, cervical myelopathy is a progressive disease with stepwise deterioration in functional ability spanned by time periods of no disease progression.

Surgical outcomes for patients with cervical myelopathy have been shown to correlate strongly with patient age and duration of symptoms prior to surgery. Older patients cannot typically expect the same level of recovery as younger ones, and the earlier the surgery is performed in the course of the disease, the better the prognosis.49 The three primary surgical interventions to treat cervical myelopathy are anterior cervical discectomy and fusion, arthroplasty, and posterior decompression with either a laminectomy or laminoplasty.

Anterior cervical discectomy and fusion and arthroplasty are typically favored in cases where three or fewer spinal levels require decompression or the compressive lesion is located in the anterior spine (ie, large disc herniation). Posterior decompression with laminectomy or laminoplasty is used to decompress more than three levels.31 Arthroplasty has been shown to produce results similar to or better than those with anterior cervical discectomy and fusion in treating myelopathy while maintaining greater range of motion in patients11 (see case 2).

Laminectomy or laminoplasty also is indicated in cases where the anterior column has already been fused previously.31 Instrumentation is nearly always used posteriorly with laminectomy, except in patients with preserved lordosis, and confers a better prognosis than laminectomy alone.31 These surgical interventions have been shown to improve symptoms such as gait difficulty and motor deficits in as many as 90% of patients50 and neurological symptoms in 55% of patients.51 Complications of surgery to correct cervical myelo-
pathy have been reported at 6.5%,52 with the risk for mortality increased 44-fold in patients older than age 85 years.53

Summary
Neck pain is a common cause of discomfort that affects nearly everyone at some point in his or her life. It can be associated with cervical radiculopathy or cervical myelopathy, with overlap between these categories. Diagnosis includes physical testing, electrodiagnostic testing, and radiographic imaging. Treatment ranges broadly between these three categories, with nonoperative solutions strongly favored and surgery strongly contraindicated for axial neck pain, and the opposite for myelopathy. This reinforces the need for physicians to be aware of the differentiating characteristics of these types of spinal pathologies in order to best treat these symptoms and help improve their patients’ outcomes.

Last updated on: December 6, 2012
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