Volume 5, Case 4
Linton L. Yee, MD
Kapiolani Medical Center For Women And Children
University of Hawaiʻi John A. Burns School of Medicine
A 7-year-old male was diving off a ledge when he landed head first in shallow water. He was pulled semiconscious from the water by lifeguards. While maintaining his airway, the lifeguards placed the patient in full C-spine immobilization. When the patient became more alert, he complained of pain to his upper neck region. Paramedics transported the patient to the ED.
Upon arrival, the patient is awake, alert, cooperative, and in C-spine immobilization. His vital signs are normal, and the neurologic exam is nonfocal. He continues to complain of upper neck pain.
A cross table lateral neck radiograph is obtained.
View lateral neck radiograph.
With the patient in in-line manual immobilization, the cervical collar is released, and the cervical spine is palpated. The exam is remarkable for tenderness in the upper cervical spine region. The lateral neck radiograph is suggestive of mild prevertebral soft tissue widening.
AP and odotoid open mouth views are obtained. The AP view is normal.
View the odontoid views.
This is a poorly taken radiograph. The ideal open mouth odontoid view should have the odontoid centered in the mouth with the lateral masses of C1 clearly visible. However, emergency physicians are commonly presented with such poorly positioned radiographs because it is often very difficult to properly position a patient, with neck pain. It is often impossible to obtain a satisfactory open mouth view in very young children who are not cooperative. In such patients, a CT scan may be necessary. Avoid the pitfall of misinterpreting a poorly positioned odontoid view. In this radiograph, only the lower lateral corners of the lateral masses of C1 are visible. However, this should be sufficient to make the diagnosis of a Jefferson fracture.
View the alignment of the lateral masses.
The lateral margins of the lateral masses (inferior articular facets of C1) should align with the lateral margins of the structures below it (superior articular facets of C2). The space between these two facets is the atlanto-axial joint. In this radiograph, the lateral masses of C1 are displaced outward, indicating a "bursting" of the ring of C1 (the Jefferson Fracture).
A Jefferson fracture is a compression and/or bursting fracture of C1. This unstable fracture is the result of a direct blow to the vertex of the head (axial compression load), either from a fall or from an object striking the vertex of the head. Neurologic injury is rare but can occur if there is involvement of C2.
The axial load to the head (skull and occipital condyles) focuses the stress on the C1 lateral masses, causing them to be compressed against the superior articular facets of C2. In the most classic cases, the damage to C1 usually occurs in four places, with fractures in two sites anteriorly and two sites posteriorly. The transverse diameter of the spinal canal is increased as a result of the displacement of the lateral masses. When C1 is fractured in less than four places, transverse ligament tears are common and can lead to more instability. If the transverse ligament remains intact, there will be no neurologic deficits, and the lateral cervical spine X-ray may appear normal. If the transverse ligament is ruptured, C1 will move forward on C2, and the spinal cord will be compressed.
Radiographic findings can show bilateral displacement of the C1 lateral masses when compared to the C2 articular pillars. There can be unilateral lateral displacement of the C1 lateral mass if there is no movement of the opposite lateral mass. Routine radiographs sometimes may not show evidence of a fracture.
The open mouth odontoid view will best show the lateral displacement of the C1 lateral masses. Neck rotation can cause false positive radiographs. A pseudo-Jefferson fracture has the radiographic appearance of a true Jefferson, but is the result of cartilage artifact and the increased growth of the atlas in comparison to C2. CT of the upper cervical spine is indicated if there is any suggestion of a Jefferson fracture.
Approximately one-third of Jefferson fractures are associated with other cervical spine fractures, with C2 associated fractures being the most common.
A repeat open mouth odontoid view of our patient is obtained.
View repeat odontoid view.
The lateral (outward) displacement of the lateral masses is clearly visible in this radiograph.
View anatomic outlines for above.
The lateral masses are clearly displaced.
View normal odontoid radiographs.
These two odontoid views show the normal alignment of the lateral masses and the superior facets of C2 below them.
View our patient's CT scan.
This CT image of our patient shows the unilateral fracture of the "ring" of C1. The odontoid process is visible. The spinal cord is faintly visible posterior to the odointoid within the neural arch.
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