61 Cervical Radiculopathy

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.

This vignette illustrates the classic history of a C7 nerve root irritation. More than 80% of these radiculopathies resolve spontaneously with conservative therapy. However, on occasion the patient experiences increasingly severe pain and progressive weakness. Unresolved pain and significant weakness are the two primary indications for cervical spine surgery.

Cervical radiculopathy, due to compression of a cervical nerve root, is a common clinical problem. It affects most adult age groups and is uncommon in adolescents and children. The symptoms may be relatively minor and chronic, or acute pain, which may be associated with weakness and sensory disturbance. Although on most occasions the cervical root symptoms have a spontaneous onset, not infrequently, the symptoms begin with a specific precipitating incident, such as trauma.

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).

Table 61-1 Cervical Nerve Roots and Primary Clinical Findings