Blast-induced Mild Traumatic Brain Injury through Ear Canal: A Finite Element Study

다국어 초록 (Multilingual Abstract)

Purpose The role of ear canal in transmitting blast waves tothe brain is not clear. The goal of this work is to characterizethe influence of ear canal on blast-induced mild traumaticbrain injury through a computational approach.
Methods A three-dimensional human head model withsingle-side ear canal details was reconstructed from computedtomography images. The ear canal was positioned eitherfacing the incident blast wave or facing away from the blastwave.
Results The blast wave-head interaction has demonstratedthat the overpressure within the ear canal was substantiallyamplified when the ear directly faced the blast wave. Whenit faced away from the blast wave, the overpressure withinthe ear canal was less than the actual incident blast pressure.
Regardless of the substantial pressure differences within theear canal induced by the blast wave, the resulting intracranialpressures were almost the same for both cases.
Conclusions The blast wave-head interaction has demonstratedthat the role of the ear canal in brain dynamics, and thusbrain injury, was negligible. However, the peak overpressurewithin the ear canal exceeded the documented tympanicmembrane rupture and inner ear damage thresholds. Thiswas speculated to cause the degeneration of axons along theauditory pathway up to the midbrain. This work providedfundamental understanding of the load transmission throughthe ear canal and could serve as a platform for designingbetter protective armors.

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