Approach Considerations
With regard to laboratory studies, the following may be helpful:
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Arterial blood gas (ABG) measurements may be useful to evaluate adequacy of oxygenation and ventilation
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Lactate levels to monitor perfusion status can be helpful in the presence of shock
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Hemoglobin and/or hematocrit levels may be measured initially and monitored serially to detect or monitor sources of blood loss
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Urinalysis can be performed to detect any associated genitourinary injury
Diagnostic imaging traditionally begins with the acquisition of standard radiographs of the affected region of the spine. Investigators have shown that computed tomography (CT) scanning is exquisitely sensitive for the detection of spinal fractures and is cost effective. [34, 35] In many centers, CT scanning has supplanted plain radiographs.
A properly performed lateral radiograph of the cervical spine that includes the C7-T1 junction can provide sufficient information to allow the multiple trauma victim to proceed emergently to the operating room if necessary without additional intervention other than maintenance of full spinal immobilization and a hard cervical collar.
Noncontiguous spinal fractures are defined as spinal fractures separated by at least 1 normal vertebra. Noncontiguous fractures are common and occur in 10-15% of patients with spinal cord injury. Therefore, once a spinal fracture is identified, the entire axial skeleton must be imaged, preferably by CT scanning, to assess for noncontiguous fractures. [31, 36, 37]
Plain Radiography
In many emergency departments (EDs), radiology support is limited. If unsure of a finding, request a formal interpretation or immobilize the patient appropriately, pending formal review of the studies.
In addition, note that the failure to adequately immobilize the spine when the mechanism of injury is consistent with the diagnosis is a pitfall.
Agitated, intoxicated patients are often the most difficult to manage properly. Pharmacologic restraint may be required to allow proper assessment. Haldol and intravenous (IV) droperidol have been used successfully, even in large doses, without hemodynamic or respiratory compromise. Occasionally, rapid-sequence intubation and pharmacologic paralysis is required to manage these patients.
Physical examination and radiographic studies could be delayed until the patient is more cooperative, if his or her overall condition permits.
Radiographic views
Radiographs are only as good as the first and last vertebrae seen, therefore, radiographs must adequately depict all vertebrae. A common cause of missed injury is the failure to obtain adequate images (eg, cervical spine radiograph that incompletely depicts the C7-T1 junction). However, be aware that radiography is insensitive to small fractures of the vertebra.
Published clinical criteria have established guidelines for cervical spine radiography in symptomatic trauma patients with neck pain. The NEXUS (National Emergency X-Radiography Utilization Study) criteria and the Canadian C-spine rules were validated in large clinical trials. [38, 39, 40] These algorithms may be used to guide physicians to determine whether or not imaging of the cervical spine is required. [38, 39, 40]
The standard 3 views of the cervical spine are recommended in patients with suspected spinal cord injury (SCI): anteroposterior (AP), lateral, and odontoid.
The cervical spine radiographs must include the C7-T1 junction to be considered adequate. Subtle findings (eg, increased prevertebral soft tissue swelling or widening of the C1-C2 preodontoid space) indicate potentially unstable cervical spine injuries that could have serious consequences if they are not detected.
Dynamic flexion/extension views are safe and effective for detecting occult ligamentous injury of the cervical spine in the absence of fracture. The negative predictive value of a normal 3-view cervical spine series and flexion/extension views exceeds 99%. The incidence of occult injury in the setting of normal findings on cervical spine radiography and CT scanning is low, so clinical judgment and the mechanism of injury should be used to guide the decision to order flexion/extension views.
Anteroposterior and lateral views of the thoracic and lumbar spine are recommended for suspected injuries to the thoracolumbar spine.
Adequate spinal radiography supplemented by computed tomography (CT) scanning through areas that are difficult to visualize or are suspicious detects the vast majority of fractures with a reported negative predictive value between 99% and 100%. [34]
Computed Tomography Scanning
Computed tomography (CT) scanning is reserved for delineating bony abnormalities or fracture. Some studies have suggested that CT scanning with sagittal and coronal reformatting is more sensitive than plain radiography for the detection of spinal fractures. [34, 41]
Perform CT scanning in the following situations:
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When plain radiography is inadequate or fails to visualize segments of the axial skeleton
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Convenience and speed: If a CT scan of the head is required, then it is usually simpler and faster to obtain a CT of the cervical spine at the same time. Similarly, CT images of the thoracic or lumbar spine might be easier and faster to obtain than plain radiographs.
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To provide further evaluation when radiography depicts suspicious and/or indeterminate abnormalities
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When radiography depicts fracture or displacement, CT scanning provides better visualization of the extent and displacement of the fracture
Magnetic Resonance Imaging
Magnetic resonance imaging (MRI) is best for suspected spinal cord lesions, ligamentous injuries, or other soft-tissue injuries or pathology. This imaging modality should be used to evaluate nonosseous lesions, such as extradural spinal hematoma; abscess or tumor; disk rupture; and spinal cord hemorrhage, contusion, and/or edema.
Neurologic deterioration is usually caused by secondary injury, resulting in edema and/or hemorrhage. MRI is the best diagnostic image to depict these changes.
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American Spinal Injury Association (ASIA) method for classifying spinal cord injury (SCI) by neurologic level.
