Cervical Disk Herniation


Etiology. Cervical disk disease is likely multifactorial, with contributing factors ranging from advancing age to neck trauma to heavy lifting to smoking. The nucleus pulposus in the middle of the disk dehydrates with age, placing more stress on the circumferential annulus fibrosus. Tears in the annulus may permit a sudden herniation of the nucleus—a ruptured disk. Alternatively, chronic annular bulging or nuclear herniation may incite a bony reparative process (spondylosis), leading to the formation of extensive bony spurs (osteophytes). These spurs are generally located along the anterior portion of the disk interspace or posteriorly, within the intervertebral foramen.


Osteophytes or ruptured disks produce neurologic symptoms when they compress the spinal cord or adjacent spinal nerve roots. The cervical nerve roots are most susceptible to injury at the point where they enter the intervertebral foramen (neuroforamen), a space delineated by the uncovertebral joint (anteromedially), the facet joint (posterolaterally), intervertebral disks and the vertebral end plates (medially), and by the pedicles of the vertebral bodies (above and below).


Symptoms. The first manifestation of cervical disk disease is often cervical radiculopathy, with symptoms and signs referable to compression of a cervical nerve root. The cervical nerve roots exit above the vertebral body of the same number, with the exception of the C8 root, which emerges at the C7-T1 interspace. Thus a lesion of the C5-6 disk produces C6 radiculopathy. Spondylosis is implicated in cervical nerve root compression about three times more often than acute disk rupture and most frequently involves the C6 or C7 nerve root. The C5 and C8 nerve roots are involved less often and the T1 root only rarely.


Cervical and unilateral arm pain is the most common symptom of cervical disk disease, and patients often complain of numbness or weakness in the involved arm. Occasionally, pain also involves the shoulder, occiput, or anterior chest. Cervical tenderness is present, and range of motion in the neck is decreased. Hyperextension and rotation of the neck toward the painful side (Spurling’s maneuver) decrease the diameter of the neural foramen and may exacerbate radicular symptoms.


Clinical Diagnosis. Neurologic examination, with careful attention to motor, reflex, and sensory findings in the upper extremities, often reveals a diagnostic constellation of signs. C5 radiculopathy usually causes weakness of shoulder external rotation (infraspinatus muscle) and shoulder abduction (supraspinatus and deltoid muscles), with decreased biceps and brachioradialis reflexes and hypalgesia over the lateral shoulder. C6 radiculopathy is characterized by diminished sensation over the thumb and index finger; however, the pattern of weakness and abnormal reflexes may be difficult to distinguish from C5 radiculopathy due to overlap between the C5 and C6 myotomes. Of note, forearm pronation (pronator teres muscle) is more likely to be involved with injury to the C6 root. In C7 radiculopathy, weakness is noted in the triceps brachii and extensor muscles of the wrist. The triceps reflex is usually decreased or absent, and sensation over the index and middle fingers is often decreased. C8 radiculopathy causes intrinsic hand muscle weakness affecting the finger abductors, adductors, and flexors. The triceps reflex may also be decreased, and sensation may be diminished over the ring and little fingers. The rare T1 radiculopathy may be associated with weakness of the intrinsic hand muscles, particularly abduction of the thumb (abductor pollicis brevis muscle), and Horner syndrome (ptosis, miosis, and anhidrosis), which results from disruption of the sympathetic outflow to the face and eye via the root of C8 or T1, or both.


Treatment. The majority of patients who have symptoms and signs of cervical radiculopathy respond to conservative treatment, including activity modification, use of a soft cervical collar to immobilize the neck for a brief period, mild analgesics, anti-inflammatory medications, and muscle relaxants as required. In some cases, cervical traction and epidural steroid injections may also be considered. If symptoms persist beyond 2 to 4 weeks, further testing, including cervical magnetic resonance imaging (MRI) and electromyography (EMG) may be indicated. If the findings suggest significant nerve root compression in the setting of progressive neurologic deficits or intractable pain, surgical therapy may be considered. Cervical root decompression may be accomplished by an anterior or posterior approach through the neck. However, epidemiologic data suggest that up to 90% of patients improve with conservative treatment alone.


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Sep 2, 2016 | Posted by in NEUROLOGY | Comments Off on Cervical Disk Herniation

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