Cervical spine injuries are the most feared of all spinal injuries because of the potential for serious neurologic sequelae. Morbidity and mortality related to cervical spine injuries depend on the mechanism of injury and the level of traumatic insult. Greater morbidity results from higher levels of cervical spine injury, with craniocervical junction injuries being associated with the highest mortality. A third of injuries are sustained at the C2 level, and one half of injuries occur at the level of C6 or C7. Most fatal cervical spine injuries affect the upper cervical levels: the craniocervical junction, C1, or C2.
Cervical spine injuries are best classified according to the mechanisms of injury, which include flexion, flexion-rotation, extension, extension-rotation, vertical compression, lateral flexion, and imprecisely understood mechanisms that may result in odontoid fractures and atlanto-occipital dislocation. Inaccurate assessment and diagnosis of cervical spine injuries is still a common problem in trauma medicine. The incidence of delayed diagnosis is said to be 5-20%.
The National Emergency X-Radiography Utilization Study (NEXUS) and the Canadian Cervical Rules (CCR) are well-established clinical criteria for exclusion of clinically significant cervical spine injury.
The quality of the standard radiographs varies greatly; their negative quality and predictive value decreases when the severity of the injury increases, and MDCT has replaced radiography as the initial imaging modality to evaluate suspected cervical spine injuries. MDCT and MRI are complementary, and both may be needed to define injuries and determine management. MDCT rapidly evaluates the bones, and MRI is superior for detecting ligament and cord injuries.
When cervical trauma exists, it may be at multiple levels, justifying the fact that if treatment is to be instituted, imaging should include the upper and lower cervical hinges.
The quality of the standard radiographs varies greatly; their negative quality and predictive value decreases when the severity of the injury increases.
(See the cervical spine illustrations below.)
Schematic lateral view of the cervical spine. A=anterior spinal line; B=posterior spinal line; C=spinolaminar line, SC=spinal canal.
Illustration of the C1 arch (superior surface view) with multiple breaks in the ring, consistent with a Jefferson fracture.
Illustration of the upper cervical spine (side view) with bilateral fractures through the pedicles of C2, consistent with a hangman fracture. When displacement is less than 3 mm, it is classified as type I; when it is greater than 3 mm, it is classified as type II (Levine classification).
Illustration of C2 (front view) with a break through the odontoid process. Type I fracture is classified as an avulsion of the tip of the dens. Type II fractures occur at the base of the dens. Type III fractures extend from the odontoid into the body of the axis.
Illustration of the cervical spine (side view) showing a fracture of the anterior inferior corner of the vertebral body and disruption of the interspinous stabilizing ligaments. This type of injury is often called a flexion tear drop fracture due to the resemblance of the vertebral corner fracture to a tear drop.
CT scanning is the most efficient technique for not only detecting but also formally eliminating an injury. MRI is indicated in patients with a neurologic deficit. Ligamentous injuries are often missed on conventional radiographs and CT, which is an indication for dynamic MRI.
CT cannot visualize the spinal cord or the surrounding soft tissues to the same degree as MRI. The potential benefits of MRI are that it can identify ongoing spinal cord compression; depict soft tissue structures that are responsible for compression, including disc herniation, epidural hematoma, intramedullary hematoma, and preexisting canal stenosis; detect ligamentous instability at the level of injury or at other spinal levels; and identify vertebral artery injury. Furthermore, certain MRI features may correspond to the degree of tissue injury and can help predict neurologic, functional, and safety outcomes.
Johansson described 3 severely injured patients who had been extensively examined without any findings of structural lesions but were diagnosed by functional MRI to have injuries in the CCJ region. These injuries were confirmed at surgery, and after surgical stabilization, the medical condition was highly improved.
Ovadia et al conducted a retrospective study on 860 patients seeking compensation following whiplash injury and concluded that the initial radiograph taken in the emergency room was the best imaging modality and probably the only one needed routinely following whiplash injury.
Platzer et al looked at the frequency and reasons for delayed or missed diagnosis at a level 1 trauma unit with a view to provide recommendations for optimal examination of patients with suspected cervical spine injuries. The authors suggested that for optimal examination of patients with suspected cervical spine injuries, specific diagnostic algorithms are needed, including complete sets of proper radiographs with functional flexion/extension views, secondary evaluation of the radiographs by experienced staff, and further radiologic examinations (CT, MRI) if evaluation of standard views is difficult. In this study, the diagnostic failure rate was 4.9%. In 44% of patients, radiologic misinterpretation was responsible for delay in diagnosis; in 28%, incomplete sets of radiographs were responsible; and in 22%, the injury was missed because inadequate radiographs did not show the level of injury.
Nontraumatic upper cervical spine instability can result from abnormal development of osseous or ligamentous structures or from gradually increasing ligamentous laxity associated with connective tissue disorders. Such instability can lead to compression of the spinal cord during movement of the cervical spine. Establishing a correct diagnosis includes performing a thorough physical examination as well as evaluating radiographic relationships and measurements.
Intraoperative ultrasonography is a useful noninvasive technique to monitor, and to reduce the potential for, spinal cord compromise when a posterior surgical approach is used for complex spinal fractures. Intraoperative ultrasonography has also been found to be useful in localizing posttraumatic subarachnoid and spinal cord cysts. Ultrasound imaging needs dedicated training and remains an operator-dependent technique.
American College of Radiology recommendations
ACR recommendations include the following
Imaging is not recommended for initial imaging of patients 16 through 65 years of age who are suspected of having acute blunt cervical spine trauma when it is not indicated by NEXUS or CCR clinical criteria and the patient meets low-risk criteria.
CT cervical spine without IV contrast is usually appropriate for the initial imaging of patients 16 years or older with suspected acute blunt trauma of the cervical spine when imaging is indicated by NEXUS or CCR clinical criteria.
MRI cervical spine without IV contrast is usually appropriate as the next imaging study for patients 16 years or older with suspected acute blunt trauma of the cervical spine and confirmed or suspected cervical spinal cord or nerve root injury, with or without traumatic injury identified on cervical CT.
CT cervical spine without IV contrast and MRI cervical spine without IV contrast are usually appropriate for patients 16 years or older with acute cervical spine injury detected on radiographs and treatment planning for mechanically unstable spine.
CTA head and neck with IV contrast or MRA neck without and with IV contrast is usually appropriate as the next imaging study for patients 16 years or older with suspected acute blunt trauma of the cervical spine and clinical or imaging findings suggesting arterial injury with or without positive cervical spine CT.
MRI cervical spine without IV contrast is usually appropriate as the next imaging study after CT cervical spine without IV contrast for obtunded patients 16 years or older with suspected suspected acute blunt trauma of the cervical spine and no traumatic injury identified on cervical spine CT.
MRI cervical spine without IV contrast is usually appropriate as the next imaging study after CT cervical spine without IV contrast for patients 16 years or older with suspected acute blunt trauma of the cervical spine and clinical or imaging findings suggesting ligamentous injury.
CT cervical spine without IV contrast, MRI cervical spine without IV contrast, or radiographs of the cervical spine may be appropriate for patients 16 years or older with suspected acute blunt trauma of the cervical spine and as follow-up imaging for patients with no unstable injury demonstrated initially but kept in collar for neck pain and no new neurologic symptoms, including whiplash-associated disorders.
CT thoracic and lumbar spine without IV contrast is usually appropriate for the initial imaging of patients 16 years or older with blunt trauma meeting criteria for thoracic and lumbar imaging. Thoracic and lumbar spine CT reconstructions can be performed from concurrently obtained CT imaging of the thorax or abdomen and pelvis in trauma patients who have undergone imaging for soft-tissue injuries without the need for additional radiation exposure.
MRI thoracic and lumbar spine without IV contrast is usually appropriate as the next imaging study for patients 16 years or older with neurologic abnormalities and acute thoracic or lumbar spine injury detected on radiographs or noncontrast CT.
For more information on cervical spine injuries, see the Medscape Reference articlesCervical Spine Anatomy, Cervical Spine Fracture in Emergency Medicine, and Cervical Spine Injuries in Sports.