Thoracic and lumbar fractures and dislocations

Pearls

Stable if two or more of the spinal columns are intact:
Anterior (anterior longitudinal ligament, annulus fibrosus, ant. half of the vertebral body)
Middle (posterior longitudinal ligament, posterior annulus fibrous, and post. half of vertebral body
Posterior (supraspinous and interspinous ligaments, facet joint capsule)
Unstable if:
50% loss of vertebral height
Kyphotic angulation around the fx:
>30o for compression fx
> 25o for burst fx
Neurologic deficit

Wedge compression fracture
Only unstable if posterior ligament complex ruptures (requires a rotational force)
Suspect instability and obtain CT if:
Severe compression (>50% loss of vertebral height)
Kyphosis >30o
Rotational component to the injury
Compression fx at multiple sites
Posterior cortex abnormality
Burst fracture
Unstable
Can occur with or without injury to posterior elements (posterior involvement increases risk for neuro deficits)
Be certain not to mistakenly call a burst fracture a wedge fracture
Obtain CT if unsure
Flexion-distraction Injuries (lap belt)
Obtain sagittally reconstructed CT if suspect lap-belt mechanism or flexion-distraction
Unstable
Intra-abdominal injuries more commonly associated than neuro deficits
Chance Fx
Lap belt worn above the pelvic bones without a shoulder harness
Forceful flexion at the lap belt > compressive failure of the ant and middle columns
One or both articular processes fx > upper vertebrae anteriorly dislocates
Imaging
Compression fx + increased posterior interspinous spaces caused by distraction
Translational
Massive direct trauma to the back > failure of all 3 columns
Almost invariably demonstrate neuro deficits

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