Imaging for a cervical injury is generally a standard requirement for all trauma patients. Cervical collars are not removed until the films are read. NEXUS does allow modifications to this rule if a patient is not exhibiting neurological deficits, are alert and not confused, they do not complain of any midline pain or tenderness, and they are not intoxicated.
Using plain x-rays for a quick assessment of fractures, alignment and soft tissue swelling is typically the first method used to evaluate a spinal cord injury. Anteroposterior, open-mouth odontoid and lateral views are included in a complete x-ray set. If a lateral mass or facet injury is suspected, an oblique view may be required. An evaluation must include a visual check of all cervical vertebrae and the top of T1. If the lower vertebrae and T1 are not seen, a swimmer’s view should be used.
Any neurological signs and/or symptoms seen in a set of normal x-rays require further imaging.
Centers that have CT scanning readily available can use this method to screen TCSI cases. Studies indicate this type of screening has a higher sensitivity for detecting spinal fractures. A CT can be done without moving the patient from the supine position. This method can also look for potential head injuries at the same time.
Any abnormalities viewed in the original CT are reevaluated with a more detailed scan of the area in question. If a spinal cord injury is suspected, patients who appear to have normal plain x-rays should undergo CT scanning for verification. The CT can also assess the patency of the spinal cord.
If an MRI is not available, myelography can be used to evaluate spinal cord injury.
Magnetic resonance imaging or MRI does not have any specific indications for determining an acute TCSI.
An MRI is ideal for viewing intervertebral discs, spinal ligaments, paraspinal soft tissues and can better detect epidural hematomas versus the CT. The CT is better used for assessing bone structures. MRI is not sensitive to cord damage during the early stages of TCSI. An MRI may also interfere with pacemakers, life sustaining machines and metallic foreign bodies. Because a patient is enclosed within an MRI, monitoring vital signs is difficult as well as maintaining an airway.
Regardless of the disadvantages to an MRI, the information, the screening can reveal is very valuable. It can provide information about the extent of the injury which directly affects prognosis and treatment. Patients who have a normal CT but are suspected to have a TSCI can benefit from an MRI’s ability to detect epidural hematomas, disc injury or occult ligamentous.
Spinal cord injury without radiographic abnormality is a type of TSCI that was created before MRIs were used. Patients with a suspected spinal cord injury without evidence of a vertebral injury on plain x-rays or CT are considered to have SCIWORA.
One explanation that is common with this type of occurrence is a transient ligamentous deformation with spontaneous reduction. Children are more prone to this due to weak paraspinal muscles. Lax soft tissue, elastic spinal ligaments also contribute to the susceptibility to protect the spinal cord from force. A number of other conditions may be responsible for a SCIWORA diagnosis that can be detected with an MRI. They include epidural or intramedullary hemorrhage, radiographically occult intravertebral disc herniation, fibrocartilaginous emboli as a result of an intravertebral ruptured disc into the radicular artery or traumatic aortic dissection with spinal cord infarction.
Myelography
When MRI is available, myelography is rarely if ever used, but remains an alternative in combination with CT when MRI cannot be performed and spinal canal compromise is suspected. More on myelography for SCI.