Spinal Burst or Compression Fractures within Automotive Crashes Due to Vertical Force Components

The purpose of this research was to present and analyze a previously unreported mechanism of injury within the automotive crash environment - spinal burst or compression fractures due to a vertical force component. Spinal burst fractures are comminuted fractures of the vertebral body which are often associated with retropulsed bone fragments into the spinal. Compression fractures are less traumatic fractures of the vertebral body with minimal comminution. Both fracture types can have varying degrees of neurologic deficit. The mechanism of injury is hypothesized to be a high energy compressive load along the axis of the spine initiated through the buttocks and pelvis or through torso augmentation (inertial loading of the lumbar spine by the torso).

Four crashes are presented as evidence of this injury mechanism within the automotive crash environment: two in the United States and two in Germany. All crashes involved a vertical force component to the wheels of the vehicle and subsequently to the occupants. Injuries included burst or compression fractures of the lumbar spine (3 cases) and the thoracic spine (1 case) with varying degrees of neurologic deficit. Injured occupants were males and females of various age (mean 30.5 ± 8 years), size, and physical condition. The range of axial loads experienced by the occupants in two of the cases was estimated between 10 and 20 Gs.