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Indications Who needs radiographic studies of the cervical spine? Indications for X-ray are: 1. Mental status less than alert or intoxicated 2. Reports neck pain 3. Midline neck tenderness 4. Neurologic signs and symptoms 5. Distracting injury (i.e. painful injuries elsewhere, e.g. extremity fractures) Not all trauma patients with a significant injury need c-spine films. Criteria for excluding cervical spine fractures on a clinical basis are: no neck pain, no neck tenderness on palpation, having full, painless, active range of motion of c-spine, no history of loss of consciousness, no mental status change, no neurologic deficit from neck injury, and no distracting symptoms. If patient meets all these criteria, cervical spine injury is excluded on clinical basis and the cervical collar may be removed. Question: A patient arrived at the ED on backboard and a cervical collar. He has a blood alcohol level of 0.2. He does not complain of any neck pain. Shoud he get a complete cervical series? (push the button for answer) Plain Films Plain films provide the quickest way to survey the cervical spine. An adequate spine series includes three views: a true lateral view (which must include all seven cervical vertebrae as well as the C7-T1 junction), an AP view, and an open-mouth odontoid view. These three views do not require the patient to move his neck, and should be obtained without the removal of the cervical collar. The Lateral View The single most important radiographic examination of the acutely injured cervical spine is the horizontal-beam lateral radiograph that is obtained before patient is moved. This film should be obtained and examed before any other films are taken. All 7 cervical vertebrae and C7-T1 junction must be visualized because the cervicothoracic junction is a common place for traumatic injury. Visualization of C7-T1 may be limited by the amount of soft tissue in the shoulder region and can be enhanced by: 1. traction on arms if no arm injury is present, or, 2. swimmer's view (taken with one arm extended over the head). Repeat lateral views with the cervical collar removed may also help in clarifying subtle abnormalities. The lateral view is obtained as follows: AP and Odontoid Views The complete radiographic examination includes AP and open-mouth views. If there are no obvious fractures or dislocations on the lateral view and the patient's condition permits, then proceed with the AP and the open-mouth views. It is important to obtain technically adequate films. The most frequent cause of overlooked injury is an inadequate film series. Patient should be maintained in cervical immobilization, and plain films should be repeated or CT scans obtained until all vertebrae are clearly visible. The AP view and Odontoid view are obtained as follows: Flexion and Extension Views What if no fracture is seen on initial films and pain is present? Flexion and extension views may be used if a pure soft tissue injury is suspected or an injury of questionable stability is noted. The patient should perform the flexion and extension voluntarily. Flexion/extension views are absolutely contraindicated in documented unstable injuries. CT Up to 20 % of fractures are missed on conventional radiographs. CT can help. CT scan is not mandatory for every patient with cervical spine injury. Most injuries can be diagnosed by plain films. However, if there is a question on the radiograph, CT of the cervical spine should be obtained. CT scan are particularly useful in fractures that result in neurologic deficit and in fractures of the posterior elements of the cervical canal (e.g. Jefferson's fracture) because the axial display eliminates the superimposition of bony structures. The advantages of CT are: 1. CT is excellent for characterizing fractures and identifying osseous compromise of the vertebral canal because of the absence of superimposition from the transverse view. The higher contrast resolution of CT also provides improved visualization of subtle fractures. 2. CT provides patient comfort by being able to reconstruct images in the axial, sagittal, coronal, and oblique planes from one patient positioning. The limitations of CT are: 1. difficult to identify those fractures oriented in axial plane (e.g. dens fractures). 2. unable to show ligamentous injuries. 3. relatively high costs. At the University of Virginia, the CT protocol for cervcial spine trauma to rule out fracture or dislocation is as follows: patient is put on a supine position in the CT scanner. Patient is scaned from top of the vertebral body above the fracture or question of fracture to bottom of the vertebral body below the fracture with slice thickness of 1.5 mm and 1.5 mm spacing. Sagittal and coronal reconstructions are done in all cases. Click here to see an example of coronal reconstruction. MRI MRI is indicated in cervical fractures that have spinal canal involvement, clinical neurologic deficits or ligamentous injuries. MRI provides the best visualization of the soft tissues, including ligaments, intervertebral disks, spinal cord, and epidural hematomas. The advantages of MRI are: 1. excellent soft tissue constrast, making it the study of choice for spinal cord survey, hematoma, and ligamentous injuries. 2. provides good general overview because of its ability to show information in different planes (e.g. sagital, coronal, etc.). 3. ability to demostrate vertebral arteries, which is useful in evaluating fractures involving the course of the vertebral arteries. 4. no ionizing radiation. The disadvantages of MRI are: 1. loss of bony details. 2. relatively high cost. At the University of Virginia, the protocol for MRI in cervical spine trauma follows five sequential scans: T1 turbo spin echo in sagittal plane, Turbo T2 in sagittal plane, 2D flash in sagittal plane, 2D flash in axial plane and T1 turbo spine echo in axial plane. Here is an example of a MRI image of the cervical spine demostrating a ligamentous injury. Notice that the spinal cord is also very well delinated. A dens fracture is not obvious on the lateral film, but is clearly revealed on MRI. Interpretation It is important to approach a cervical spine film series in a stepwise fashion. One can follow an easily remembered mnemoic AABCDS. On each film, sequentially evaluate adequacy, alignment, bone, cartilage, disc, and soft tissue. A adequacy, A alignment, B bone, C cartilage, D disc, and S soft tissue. The Lateral View The lateral view is the most important film of all. Interpretation follows the mnemonic AABCDS. First, is the film Adequate? An adequate film should include all 7 vertebrae and C7- T1 junction. It should also have correct density and show the soft tissue and bony structures well. Alignment Assess four parallel lines. These are: 1. Anterior vertebral line (anterior margin of vertebral bodies) 2. Posterior vertebral line (posterior margin of vertebral bodies) 3. Spinolaminar line (posterior margin of spinal canal) 4. Posterior spinous line (tips of the spinous processes) These lines should follow a slightly lordotic curve, smooth and without step-offs. Any malalignment should be considered evidence of ligmentous injury or occult fracture, and cervical spine immobilization should be maintained until a definitive diagnosis is made. Sometimes, misalignment may be physiological. Subluxation Pseudosubluxation