Access Type

Open Access Dissertation

Date of Award

1-1-2011

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Biomedical Engineering

First Advisor

Cynthia A. Bir

Second Advisor

Pamela J. VandeVord

Abstract

Shock wave induced brain injury remains a field of research that has great consequences for the rehabilitation of soldiers and civilians that are exposed to an explosion. As such, for the research to be successful in developing strategies to mitigate the effects of these injuries, appropriate research methods need to be developed. Animal models are currently employed to understand the brain's response to a shock wave exposure. Unfortunately no criteria have been established that indicates in what way the mechanical inputs that the cells in an animal's brain are subjected to are similar to a human. The purpose of this dissertation was to investigate these biomechanical responses.

To address this question, the biomechanical responses of the rat, pig, and post mortem human subject were analyzed. Each of the species was exposed to multiple shock waves within a shock tube. Skull strain was measured using strain gages and intracranial pressure was measured using fiber optic pressure sensors. The effect of orientation was also addressed for the cadaver and the porcine.

The results of the project indicate that for all three species, as the incident shock wave amplitude increases, the peak strain and ICP also increases. Also, the response of the head is unique to orientation. A front facing head will respond differently than a side facing head. The relationships between skull strain and ICP were also demonstrated. Skull flexure has a dominate effect on the ICP response. Additionally key characteristic waveforms describing the skull surface and ICP wave dynamics were identified.

Overall this project provides much needed information in the field of blast biomechanics. The results of the study indicate that each species will experience pressure wave profiles in the brain partially by means of skull flexure. And that the intracranial pressure environment is dependent on intensity, orientation of the head, and species being tested. It is possible that the responses of each species can be simplified into relative contributions of the identified waveforms. This research provides a basis for further studies that will either investigate methods for mitigating the effects of shock wave exposure or investigating brain cell response to pressure waveforms that are generated within the brain when exposed to a shock wave.

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