Neck Pain in Adults _________________________________________________________________________
MRI is contraindicated in patients with certain implanted devices, but MRI scanners compatible with pacemakers are now available. Some patients have panic reactions during MRI from claustrophobia and require mild sedation [51; 103]. Computed Tomography (CT) MRI is superior at imaging soft tissue abnormalities and potential neurologic compromise, while CT better delineates bony pathology by producing multiple 2- and 3-dimensional images of spinal segments [7]. CT alone has limited value in assessing cervical radiculopathy but is useful for visualizing degenerative spine and facet changes, spinal alignment, fractures, herniated disks, spinal and foraminal stenosis, and osteophyte formation, especially when not clearly shown on x-ray [23; 24; 50; 58; 103]. It is important to avoid unnecessary CT scanning to limit patient radiation exposure and associated carcinogenic risk [103]. CT Myelography Myelogram followed by CT scan evaluates the spinal canal, its relationship to the spinal cord, and nerve root impingement from disk, spur, or foraminal encroachment. CT myelography is superior to MRI in detecting encroachment but is reserved for complex cases due to greater expense and morbidity or when MRI is unavailable, intolerable to the patient, or contraindicated [19; 51]. Provocative Cervical Diskography Provocative cervical diskography is the only procedure that can identify a disk as the pain generator. In this test, contrast dye is injected into the nucleus pulposus to visualize disk architecture and provoke a pain response. Discomfort and invasiveness make this procedure less desirable than cervical MRI, which provides much of the anatomic information. Possible complications include diskitis, epidural abscess, quadriplegia, stroke, pneumothorax, and nerve and spinal cord injury [51].
MRI often misses significant tears, which diskography can reveal as diskogenic source of cervical pain. As noted, while MRI can identify most painful disks, it has relatively high error rates [41]. Electrodiagnostic Tests Electromyography and nerve conduction studies are the standard for evaluating cervical spine neurologic function and have advantages of limited cost and morbidity [51]. With persistent radicular symptoms, electromyography can help identify injuries to cervical nerve roots, brachial plexus, or peripheral nerves [16]. It may show nerve injury missed by imaging studies that only show structural injury [41]. Electromyography shows abnormalities with high specificity in cervical radiculopathy, diagnosed when two muscles innervated from the same nerve root are abnormal. Multiple muscles should be examined, including the paraspinals [11; 12; 22]. Nerve conduction studies are useful when extremity pain rather than cervical pain is more severe [7]. Initial Imaging Initial imaging is recommended for some patients when they first present for medical attention with neck pain or symptom complaints. Acute Cervical Spine Injury The Canadian C-spine Rule identifies patient risk of cervical spine injury and appropriate diagnostic imaging. “Dangerous mechanism of injury” is defined as falling from a height greater than 3 feet or axial load to the head from diving, high-speed or rollover motor vehicle accident, ejection from a motor vehicle, accident involving motorized recreational vehicles or horse riding, or bicycle collision [110]. The Canadian C-spine Rule assesses high, low, or no patient risk of cervical spine injury ( Table 4 ). Importantly, neck movement is unsafe to assess in high-risk patients [108; 110].
ASSESSMENT OF RISK LEVEL FOR CERVICAL SPINE INJURY
High Risk One or more of the following factors: • Dangerous mechanism of injury • Age 65 years or older • Paresthesia in upper or lower limbs Low Risk Patients unable to rotate their neck 45° left and right and one or more of the following factors: • Involved in a minor rear-end motor vehicle accident • Comfortable in a sitting position
• Ambulatory at any time since the injury • No midline cervical spine tenderness • Delayed onset of neck pain No Risk Patient has one low-risk factor and can rotate his/her neck 45° left and right. Source: [110]
Table 4
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