Comparison of standard automotive industry injury predictors and actual injury sustained during significant whiplash events.

PURPOSE

We present a unique opportunity to compare standard neck injury criteria (used by the automotive industry to predict injury) with real-life injuries. The injuries sustained during, and the overall kinematics of, a television demonstration of whiplash mechanics were used to inform and validate a vertebral level model of neck mechanics to examine the relevance of current injury criteria used by the automotive industry.

METHODS

Frontal and rear impact pulses, obtained from videos of sled motion, were used to drive a MADYMO human model to generate detailed segmental level biomechanics. The maximum amplitude of the frontal and rear crash pulses was 166 ms and 196 ms, respectively, both with a duration of 0.137 s. The MADYMO model was used to predict standard automotive neck injury criteria as well as detailed mechanics of each cervical segment.

RESULTS

Whilst the subject suffered significant upper neck injuries, these were not predicted by conventional upper neck injury criteria (Nij and Nkm). However, the model did predict anterior accelerations of C1 and C2 of 40 g, which is 5 times higher than the threshold of the acceleration for alar ligament injury. Similarly, excessive anterior shear displacement (15 mm) of the skull relative to C2 was predicted. Predictions of NIC, an injury criterion relevant to the lower neck, as well as maximum flexion angles for the lower cervical segments (C3-T1) exceeded injury thresholds.

CONCLUSION

The criteria used by the automotive industry as standard surrogates for upper neck injury (Nij and Nkm) did not predict the significant cranio-cervical junction injury observed clinically.