Citation

Stemper BD, Baisden JL, Yoganandan NA, Pintar FA, DeRosia J, Whitley P, Paskoff GR, Shender BS. Proc. IRCOBI 2012; 40: 217-224.

Copyright

(Copyright © 2012, International Research Council on Biomechanics of Injury)

DOI

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PMID

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Abstract

Military occupants can be exposed to more severe environments than civilian. High-rate vertical acceleration occurs under a variety of military activities and spinal injury distribution may be dependent upon acceleration characteristics. This preliminary investigation determined spinal fracture patterns in post-mortem human subject (PMHS) lumbar spines for two simulated environments: catapult phase of aviator ejection and helicopter crash. Vertical accelerations simulating ejections had peak magnitudes of 20-22 G with rates of onset less than 525 G/s. Accelerations simulating helicopter crashes had peak magnitudes of 44-65 G with rates of onset exceeding 1000 G/s in one specimen and exceeding 2000 G/s in two specimens. In this study, two lumbar spines were subjected to simulated ejections and three spines were subjected to simulated helicopter crashes. Results demonstrated fractures primarily affecting vertebral bodies and a majority occurring under axial compression mechanisms. Although fracture types were not different between environments (burst and anterior compression fractures occurred in each), injury location migrated caudally for higher severity accelerations. Whereas compression fractures affected the L1 spinal level for ejection accelerations, fractures were distributed between L1 and L4 levels for helicopter crash accelerations. More severe helicopter crash accelerations (60 g, 2000 g/s) demonstrated injuries affecting L2-L4 levels. Results from this experimental study are validated by clinical reports of military personnel, wherein caudal injury locations were evident for higher severity accelerations such as helicopter crashes.