Clinical Vignette

A 42-year-old woman presented with a 2-week history of increasingly severe neck pain with radiation to the back of her right upper arm. In retrospect, she had developed very acute right medial scapula pain 4 weeks earlier after carrying a heavy briefcase to a meeting; this discomfort improved within 10 days. However, she then developed the cervical and right arm discomfort; this was associated with numbness and tingling in her second and third fingers. She was an active tennis player and tried to play despite her discomfort but noted difficulty serving as she could not fully extend her arm. Her family physician initially treated her for “bursitis” and suggested she might also have an emerging carpal tunnel syndrome because of the hand paresthesiae. However, when the pain suddenly worsened she consulted a neurologist. The neurologist elicited a 2-year history of similar but milder intermittent pain and numbness, especially after driving long distances. Neurologic examination demonstrated modest right triceps weakness with an absent right triceps muscle stretch reflex. A trial of physical therapy was ineffective, and her symptoms significantly worsened after an afternoon of raking leaves. Further neurologic evaluation demonstrated more severe triceps weakness. A magnetic resonance imaging (MRI) of the cervical spine demonstrated a herniated disc at C6–7. A neurosurgeon performed a posterior laminoforaminotomy and microdiscectomy. This provided immediate relief of her radicular pain. Her triceps strength improved to normal in the ensuing 3 months.

Clinical Presentation

The clinical presentations of cervical radiculopathy depend on the specific root involved. It is unusual to have multiple nerve roots compressed at one time. The usual symptoms are pain, motor weakness, and sensory disturbance. Neck and/or medial scapular pain commonly occur with cervical root compression; shoulder or arm pains are often present. Typical clinical findings include both arm weakness and sensory disturbance appropriate to the affected nerve root (Fig. 61-1). Neck movement often exacerbates the radicular pain and may result in an electric shock–like sensation (Fig. 61-2). Very rarely, pressure on the spinal cord as well as the nerve root may result in concomitant evidence of myelopathy. In any patient with cervical radiculopathy, clinical examination requires careful evaluation for evidence of a myelopathy by making certain the neurologic examination does not demonstrate a spastic gait with enhanced muscle stretch reflexes, a Babinski sign, and evidence of a spinal cord sensory level.

Figure 61-1 Dermatomes and Myotomes of Upper Limb.

Figure 61-2 Cervical Disc Herniation: Clinical Manifestations.

Of the various cervical radiculopathies, C7 nerve root is the most commonly affected. It exits the spinal canal between C6 and C7. Typically, compression leads to pain in the posterior arm. Unlike C5 and C6 lesions, C7 has little functional overlap with other roots. C7 innervates the triceps muscle, which extends the elbow (see Fig. 61-2). Unless patients perform activities that demand extension of the elbow, such as hammering for a carpenter, serving in tennis, rowing, or performing pushups, many individuals with a C7 radiculopathy are unaware of significant triceps weakness. In order to best ascertain the presence of triceps weakness, the examiner must ask the patient to flex the arm at the elbow to 90 degrees and then have the patient try to extend against resistance. In contrast, if one first asks the patient to extend his arm fully, relatively subtle degrees of weakness will be missed. In repose, gravity extends the elbow in most cases. Sensory loss in C7 radiculopathy usually extends to the index and middle fingers (Table 61-1).

The C6 nerve root exits the spine between C5 and C6 vertebrae. Compression here leads to pain in the medial scapula and into the arm frequently to the lateral side of the forearm, as well as the hand and into the thumb. Motor loss overlaps with C5 root and there is weakness in the proximal arm muscles, particularly the biceps, with difficulty flexing the arm and abducting the arm at the shoulder. Sensory changes affect the thumb and index finger.

C8 is the lowest of the cervical roots, exiting the spinal column between the C7 and T1 vertebrae. When this nerve root is compressed, the pain radiates from the neck into the medial forearm and into the medial hand. If there is significant C8 compromise, patients develop weakness of their intrinsic hand muscle function. They also often complain of numbness and demonstrate sensory change in the medial hand as well as the fourth and fifth digits.

C5 is the least frequent level for radiculopathy. The C5 nerve root exits the spine between the C4 and C5 vertebral bodies. Compression of the C5 root produces pain within the medial scapula and into the upper arm; the pain rarely radiates below the elbow. There may be weakness of the deltoid resulting in difficulty carrying out tasks with the arm elevated (see Fig. 61-2). Sensory loss will be over the shoulder and upper arm and is often minimal (see Table 61-1).

When evaluating a patient with a suspected radiculopathy, it is important to define the temporal profile as well as the degree of progression of the symptoms. Has there been slow progression or rapid worsening? Has there been a plateau or improvement in the condition? How long have the symptoms persisted? The severity and quality of the pain and its provocative factors provide other useful information. In particular, does the arm pain worsen with movement of the neck? Is the pain of an electric quality? It is important to palpate the axilla or supraclavicular fossa, as a mass there could suggest the presence of an extraspinal tumor (Fig. 61-3) or a tumor of the brachial plexus (Fig. 61-4).

Figure 61-3 Extraspinal Tumor.

Figure 61-4 Desmoid Tumor.

Differential Diagnosis

A modest number of pathologic conditions affect the cervical spine and require consideration in the evaluation of the individual with neck pain associated with limb muscle weakness and sensory loss. Radiculopathy secondary to ruptured cervical disc is the most common cause (Fig. 61-5). Degenerative encroachment of the neural foramen from cervical spondylitic disease is another common cause. Primary or secondary neoplastic tumors of the cervical spine or vertebral infection can mimic disc herniation. Metastatic extradural tumor is the most common neoplasm within the cervical spine; the common sites of origin are breast, lung, prostate, and myeloma. The intradural extramedullary tumors, that is, schwannoma and meningioma, are also considerations. In contrast, intramedullary lesions, including a tumor or syrinx, usually present with symptoms of myelopathy. Spinal infection, especially epidural abscess, has increased in frequency; this may be due to sepsis associated with infection in the skin, wounds, urinary tract, and dental manipulation; there is a higher incidence in drug abusers and immune-suppressed patients. Patients with spinal infection usually have a great deal of spine and root pain and may have significant myelopathy. The presence of myelopathic signs, in this clinical setting, demands urgent surgical decompression. Furthermore, these patients frequently have significant spinal instability, which must be a consideration when planning surgery.

Figure 61-5 Large Right Lateral C6-C7 Disc Herniation.

On occasion, a lesion in the brachial plexus may be confused with a cervical radiculopathy. Neoplasms, either cancers or lymphoma invading the medial brachial plexus, may mimic a C8 radiculopathy; this also occurs with occult superior sulcus apical lung tumors (Pancoast syndrome). Schwannomas are the most common primary nerve tumors arising from the brachial plexus. Brachial plexitis (Parsonage–Turner syndrome) may mimic a C5 radiculopathy. Other diagnostic considerations include ulnar neuropathy and the rare neurogenic thoracic outlet syndrome.

Diagnostic Approach

Approximately 80% of patients with cervical radiculopathy improve spontaneously, and therefore imaging is often unnecessary. MR imaging studies of the spine are important in patients with unusual presentations or those who do not improve. To ensure there is no mismatch between symptoms and imaging findings, evaluate the studies carefully. It is not uncommon for asymptomatic patients to have significant abnormalities on imaging that are of no consequence. The clinical findings must correlate with imaging abnormalities in order to consider surgical treatment.

It is common practice to omit standard cervical radiographs but these may have some clinical value. Such images provide excellent visualization of the degree of spondylosis and disc degeneration and are of great importance to detect the presence of kyphosis. Flexion and extension lateral views of the spine are important in defining the presence of abnormal movement between the vertebrae.

MRI is the imaging modality of choice for evaluating the spine and spinal cord. Occasionally open MRI or CT myelography are good options for claustrophobic patients. Imaging studies will demonstrate the nerve root compression caused by disc herniation or spondylosis. A bright signal in the spinal cord on the T2-weighted image is indicative of an injury to the cord (Fig. 61-6). Additionally, it is possible to visualize tumors within the vertebrae or epidural space. Intradural tumors have a well-defined relationship to both the nerve root and spinal cord; MRI clearly demonstrates these lesions. Extramedullary tumors usually readily enhance with gadolinium; in contrast, intramedullary tumors are often difficult to differentiate from intrinsic spinal cord demyelinating lesions such as multiple sclerosis.

Figure 61-6 Cervical Spinal Stenosis.

Spinal computed tomography (CT) has limited value when used as a stand-alone diagnostic modality. However, CT used in conjunction with myelography is particularly useful in patients unable to have an MRI (e.g., because of cardiac pacemakers). Standard myelography followed by postmyelogram CT will show nonfilling of nerve root sleeves or direct compression of the nerve roots (see Fig. 61-2). It may also demonstrate pressure on the spinal cord (extramedullary lesions) as well as pathology within the cord (intramedullary lesions). CT is particularly effective for demonstration of ossification of the posterior longitudinal ligament (OPLL). Additionally reconstructed spinal CT is an excellent study when attempting to understand complex spinal deformities. We recommend electrodiagnostic studies if there is conflict between the clinical story and imaging findings or if a diagnosis other than radiculopathy is suspected, for example, brachial plexopathy.

Treatment and Prognosis

The choice of therapy for a cervical radiculopathy depends on the clinical presentation of the patient. Because most individuals improve spontaneously, early imaging and active treatment are rarely necessary unless there is significant weakness or signs of a concomitant myelopathy. Approximately 80% of patients with cervical radiculopathy secondary to either disc herniation or foraminal narrowing will improve spontaneously within 3 months. Heavy activity is restricted in individuals with acute nerve root compression. This particularly applies to activity that exerts tension on the cervical nerve roots leading to protective muscle spasm, with consequent worsening of the pain. Examples include carrying a heavy briefcase, heavy lifting, or making a bed, etc. These patients are reexamined within few weeks. Occasionally, muscle relaxants, simple analgesics, or anti-inflammatory agents are helpful adjuncts. Narcotics are used for severe pain, usually only for a limited period. Usually these modalities are successful. The good results of these conservative treatments and similarly of treatments such as traction, acupuncture, chiropractic manipulation and massage, probably owe their therapeutic success to the natural history of the condition.

For those patients with unremitting severe pain, or with significant neurologic deficit, or with evidence of myelopathy MRI is mandatory. If there is evidence of cervical disc herniation and the finding is appropriate to the clinical examination, surgery is an option.

Spine surgeons differ on the best surgical means to repair a ruptured lateral cervical disc, either an anterior or posterior approach. One approach involves anterior neck dissection, complete removal of the disc, and reconstruction commonly with spinal fusion. For a lateral disc herniation, a posterior medial facetectomy, with elevation of the nerve root and removal of the ruptured disc fragment is an option. The posterior approach is more uncomfortable than the anterior approach for the patient, but the exposure of the nerve root is superior and the patient does not have the potential long-term problems of fusion. An anterior approach is used for midline disc herniations causing cord and/or root symptoms.

If imaging demonstrates a diagnosis such as tumor or infection, then treatment is appropriately tailored. In the near future, replacement of the degenerative disc by an artificial disc may become a therapeutic option. Arthroplasty may prevent the late development of stress-related degenerative changes that can occur at levels adjacent to a fusion.