Analysis of spinal motion and loads during frontal impacts. Comparison between PMHS and ATD

F.J. López-Valdés, A. Lau, J. Lamp, P.O. Riley, D.J. Lessley, A. Damon, M. Kindig, R. W. Kent, S. Balasubramanian, T. Seacrist, M. Maltese, K.B. Arbogast, K. Higuchi, H. Tanji

54th AAAM Annual Scientific Conference - AAAM 2010, Las Vegas (United States of America). 17-20 octubre 2010

Summary:

Quantifying the kinematics of the human spine during a frontal impact is a challenge due to the multi-degree-offreedom structure of the vertebral column. This papers reports on a series of six frontal impacts sled tests performed on three Post Mortem Human Surrogates (PMHS). Each subject was exposed first to a low-speed, non-injurious frontal impact (9 km/h) and then to a high-speed one (40 km/h). Five additional tests were performed using the Hybrid III 50 th percentile male ATD for comparison with the PMHS. A 3D motion capture system was used to record the 6-degree-of-freedom motion of body segments (head, T1, T8, L2, L4 and pelvis). The 3D trajectories of individual bony structures in the PMHS were determined using bonemounted marker arrays, thus avoiding skin-attached markers and their potential measurements artifacts. The PMHS spines showed different behavior between low and high speed. While at low speed the head and upper spinal segments lagged the lower portion of the spine and pelvis in reaching their maximum forward displacement (time for maximum forward head excursion was 254.3±31.9 ms and 140.3±9 ms for the pelvis), these differences were minimal at high speed (127±2.6 ms for the head vs. 116.7±3.5 ms for the pelvis). The ATD did not exhibit this speed-dependant behavior. Furthermore, the ATD's forward displacements were consistently less than those exhibited by the PMHS, regardless of the speed. Neck loads at the atlantooccipital joint were estimated for the PMHS using inverse dynamics techniques and compared to those measured in the ATD. It was found that the axial and shear forces and the flexion moment at the upper neck of the PMHS were higher than those measured in the ATD.

Publication date: October 2010.

Citation:
López-Valdés, F.J., Lau, A., Lamp, J., Riley, P.O., Lessley, D.J., Damon, A., Kindig, M., Kent, R. W., Balasubramanian, S., Seacrist, T., Maltese, M., Arbogast, K.B., Higuchi, K., Tanji, H., Analysis of spinal motion and loads during frontal impacts. Comparison between PMHS and ATD, 54th AAAM Annual Scientific Conference - AAAM 2010, Las Vegas (United States of America). 17-20 October 2010.

IIT-10-087A