Anterolateral compression fracture of the thoracolumbar spine. A seat belt injury.

A thoracolumbar injury is reported in four patients who were involved in motor vehicle accidents while wearing shoulder-lap belt assemblies. These injuries consisted of anterolateral wedge compression of a thoracolumbar vertebra with lateral compression occurring on the side opposite the restrained shoulder. The posterior elements were disrupted contralateral to the anterolateral body compression. There was no translation in any of these fractures, and there were no neurological injuries. All fractures united without significant late disability. Although there was no gross clinical instability in these fractures, two of the three columns of the spine are disrupted, suggesting potential instability. The postulated mechanism of injury, referred to as the roll-out phenomenon, is flexion and rotation about the axis of the shoulder strap.