History
Pertinent history should include the following information:
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Information about pain onset (eg, abrupt onset suggests acute injury)
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Time since injury
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Mechanism of injury
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Percentage of axial versus peripheral pain (eg, 90% neck pain vs 10% upper limb)
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Review of systems to uncover possible systemic illness (eg, fever suggests infection, weight loss suggests malignancy), as well as any other associated symptoms, including postural changes and pain that primarily occurs at night may also indicate an etiology that warrants further investigation
Discogenic pain without nerve root involvement is typically vague, diffuse and distributed axially.
Pain referred from disc to upper limb usually is nondermatomal, and does not follow any predictable course
In a study using provocative discography for symptom mapping, Slipman et al showed that unilateral symptoms were found just as often as bilateral symptoms. Slight variation was noted for referred somatic pain originating from each disc level to the neck, shoulder, and upper thoracic region but with a great amount of overlap. [23]
Activities that increase intradiscal pressure (eg, lifting, Valsalva maneuver) intensify symptoms. Conversely, lying supine provides relief by decreasing intradiscal pressure.
Vibrational stress from driving can also exacerbate discogenic pain. Yates et al showed that vibration and shock loading provided sufficient mechanical injury to exacerbate preexisting herniations, whereas a flexed posture did not influence the distance of nucleus pulposus tracking. [24]
Depending on whether primarily motor or sensory involvement is present, radicular pain is deep, dull, and achy or sharp, burning, and electric. Such radicular pain follows a dermatomal or myotomal pattern into the upper limb. Cervical radicular pain most commonly radiates to the interscapular region, although pain can be referred to the occiput, shoulder, or arm as well. Neck pain does not necessarily accompany radiculopathy and frequently is absent.
Patients may present with distal limb numbness and proximal weakness in addition to pain. Atrophy may be present.
A study has demonstrated cervical HNP-induced thermal changes (ie, thermatomes) in specific upper extremity distributions.
Mechanical stimulation of cervical nerve roots has shown that the distribution of referred radicular symptoms (ie, dynatome) may be different from sensory deficits outlined by traditional dermatomal maps.
Physical
The patient with radicular pain also displays decreased cervical range of motion (ROM). The 3 most common maneuvers to test for cervical radiculopathy are the Spurling maneuver, shoulder abduction (relief) sign, and neck distraction test.
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Spurling maneuver: The patient's neck is extended, laterally bent, and held down and performed in the seated position. It is designed to elicit radicular symptoms. A positive test finding is reproduction of radicular symptoms distal to the neck. A positive test finding has shown a sensitivity of 40-60% and specificity of 92-100%. [25]
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Shoulder abduction sign: Active abduction of symptomatic arm, placing the patient’s hand on head, is performed in the seated position. Positive test finding is relief or reduction of ipsilateral cervical radicular symptoms. Sensitivity is 43-50%, and specificity is 80-100%. [25]
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Neck distraction test: The examiner grasps the patient’s head under occiput and chin and applies an axial traction force. It is performed in the supine position with an approximate traction force of 10-15 Kg. Positive test finding is relief or reduction of cervical radicular symptoms. Sensitivity is 40-43%, and specificity is 100%. [25]
Decreased sensation to pain, light touch, or vibration may be present in the distal upper limb. Proximal limb weakness manifests when significant motor root compromise exists, but this symptom must be differentiated from pain-related weakness.
Diminished or absent reflexes corresponding to the root level may be present. Increased upper and lower limb reflexes or other upper motor neuron signs suggest myelopathy and mandate aggressive diagnostic evaluation as well as differentiation from other causes of upper motor neuron pathology
The patient with discogenic pain without nerve root involvement demonstrates decreased cervical range of motion, normal neurologic examination, and possible pain exacerbation with axial compression and pain alleviation with distraction.
Myofascial tender or trigger points, which may be primary in origin or secondary to other pathologic processes, commonly, are palpable.
Tenderness with posteroanterior mobilization may suggest disc pathology.
Causes
HNP results from repetitive cervical stress or, rarely, from a single traumatic incident. Increased risk may accrue because of vibrational stress, heavy lifting, prolonged sedentary position, whiplash accidents, and frequent acceleration/deceleration.
DDD is part of natural aging, but it is also a consequence of poor nutrition, smoking, atherosclerosis, job-related activities, and genetics.
IDD can result from cervical trauma, including whiplash, cervical flexion/rotation injury, and repetitive use.
Cervical radiculopathy results from nerve root compression secondary to herniated disc material, stenosis, or proteoglycan-mediated chemical inflammation released from discs. Smoking and certain occupational activities also predispose patients to cervical radiculopathy.
A study by Abdalkader et al found that of 100 athletes from the 2016 Olympic Summer Games in Rio de Janeiro who, during the games, underwent spinal MRI, 126 cervical discs fell into one of the Pfirrmann disc degeneration grades, I through V. That included 55 discs (43.6%) with mild degenerative changes, 17 discs (13.5%) with moderate degenerative changes, and 1 disc (0.8%) with severe degenerative changes. Cervical DDD was most prevalent among athletes who competed in athletics, boxing, or swimming. [26]
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Disc herniation classification. A: Normal disc anatomy demonstrating nucleus pulposus (NP) and annular margin (AM). B: Disc protrusion, with NP penetrating asymmetrically through annular fibers but confined within the AM. C: Disc extrusion with NP extending beyond the AM. D: Disc sequestration, with nuclear fragment separated from extruded disc.
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Axial magnetic resonance imaging (MRI) scan (C3-C4) demonstrating left-sided posterolateral protrusion of the nucleus pulposus with compression of the cerebrospinal fluid.
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Sagittal magnetic resonance imaging (MRI) scan demonstrating cervical intervertebral disc protrusions at C3-C4 and C7-T1.
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Right C7 cervical transforaminal epidural steroid injection demonstrating epidural and radicular spread of radiologic contrast dye.
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Cervical epidural steroid injection at the C7-T1 interlaminar space.
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Cervical discography. Anteroposterior fluoroscopic image.
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Cervical discography. Lateral fluoroscopic image.
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Postdiscography axial computed tomography (CT) scan demonstrating right posterolateral subligamentous protrusion.
