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Yu X, Ghajari M. Protective Performance of Helmets and Goggles in Mitigating Brain Biomechanical Response to Primary Blast Exposure. Ann Biomed Eng 2022; 50:1579-1595. [PMID: 35296943 PMCID: PMC9652178 DOI: 10.1007/s10439-022-02936-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 02/15/2022] [Indexed: 12/02/2022]
Abstract
The current combat helmets are primarily designed to mitigate blunt impacts and ballistic loadings. Their protection against primary blast wave is not well studied. In this paper, we comprehensively assessed the protective capabilities of the advanced combat helmet and goggles against blast waves with different intensity and directions. Using a high-fidelity human head model, we compared the intracranial pressure (ICP), cerebrospinal fluid (CSF) cavitation, and brain strain and strain rate predicted from bare head, helmet-head and helmet-goggles-head simulations. The helmet was found to be effective in mitigating the positive ICP (24–57%) and strain rate (5–34%) in all blast scenarios. Goggles were found to be effective in mitigating the positive ICP in frontal (6–16%) and lateral (5–7%) blast exposures. However, the helmet and goggles had minimal effects on mitigating CSF cavitation and even increased brain strain. Further investigation showed that wearing a helmet leads to higher risk of cavitation. In addition, their presence increased the head kinetic energy, leading to larger strains in the brain. Our findings can improve our understanding of the protective effects of helmets and goggles and guide the design of helmet pads to mitigate brain responses to blast.
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Affiliation(s)
- Xiancheng Yu
- Dyson School of Design Engineering, Imperial College London, South Kensington, London, SW72AZ, UK. .,Centre for Blast Injury Studies, Imperial College London, South Kensington, London, SW72AZ, UK.
| | - Mazdak Ghajari
- Dyson School of Design Engineering, Imperial College London, South Kensington, London, SW72AZ, UK.,Centre for Blast Injury Studies, Imperial College London, South Kensington, London, SW72AZ, UK
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Unnikrishnan G, Mao H, Sajja VSSS, van Albert S, Sundaramurthy A, Rubio JE, Subramaniam DR, Long J, Reifman J. Animal Orientation Affects Brain Biomechanical Responses to Blast-Wave Exposure. J Biomech Eng 2021; 143:1096850. [PMID: 33493319 DOI: 10.1115/1.4049889] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Indexed: 11/08/2022]
Abstract
In this study, we investigated how animal orientation within a shock tube influences the biomechanical responses of the brain and cerebral vasculature of a rat when exposed to a blast wave. Using three-dimensional finite element (FE) models, we computed the biomechanical responses when the rat was exposed to the same blast-wave overpressure (100 kPa) in a prone (P), vertical (V), or head-only (HO) orientation. We validated our model by comparing the model-predicted and the experimentally measured brain pressures at the lateral ventricle. For all three orientations, the maximum difference between the predicted and measured pressures was 11%. Animal orientation markedly influenced the predicted peak pressure at the anterior position along the midsagittal plane of the brain (P = 187 kPa; V = 119 kPa; and HO = 142 kPa). However, the relative differences in the predicted peak pressure between the orientations decreased at the medial (21%) and posterior (7%) positions. In contrast to the pressure, the peak strain in the prone orientation relative to the other orientations at the anterior, medial, and posterior positions was 40-88% lower. Similarly, at these positions, the cerebral vasculature strain in the prone orientation was lower than the strain in the other orientations. These results show that animal orientation in a shock tube influences the biomechanical responses of the brain and the cerebral vasculature of the rat, strongly suggesting that a direct comparison of changes in brain tissue observed from animals exposed at different orientations can lead to incorrect conclusions.
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Affiliation(s)
- Ginu Unnikrishnan
- Department of Defense, Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD 21702; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Drive, Bethesda, MD 20817
| | - Haojie Mao
- Department of Defense, Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD 21702; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Drive, Bethesda, MD 20817
| | - Venkata Siva Sai Sujith Sajja
- Blast Induced Neurotrauma Division, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, 503 Robert Grant Drive, Silver Spring, MD 20910
| | - Stephen van Albert
- Blast Induced Neurotrauma Division, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, 503 Robert Grant Drive, Silver Spring, MD 20910
| | - Aravind Sundaramurthy
- Department of Defense, Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD 21702; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Drive, Bethesda, MD 20817
| | - Jose E Rubio
- Department of Defense, Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD 21702; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Drive, Bethesda, MD 20817
| | - Dhananjay Radhakrishnan Subramaniam
- Department of Defense, Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD 21702; The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., 6720A Rockledge Drive, Bethesda, MD 20817
| | - Joseph Long
- Blast Induced Neurotrauma Division, Center for Military Psychiatry and Neurosciences, Walter Reed Army Institute of Research, 503 Robert Grant Drive, Silver Spring, MD 20910
| | - Jaques Reifman
- Department of Defense, Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Development Command, Fort Detrick, MD 21702
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Unnikrishnan G, Mao H, Sundaramurthy A, Bell ED, Yeoh S, Monson K, Reifman J. A 3-D Rat Brain Model for Blast-Wave Exposure: Effects of Brain Vasculature and Material Properties. Ann Biomed Eng 2019; 47:2033-2044. [PMID: 31054004 PMCID: PMC6757019 DOI: 10.1007/s10439-019-02277-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 04/23/2019] [Indexed: 11/30/2022]
Abstract
Exposure to blast waves is suspected to cause primary traumatic brain injury. However, existing finite-element (FE) models of the rat head lack the necessary fidelity to characterize the biomechanical responses in the brain due to blast exposure. They neglect to represent the cerebral vasculature, which increases brain stiffness, and lack the appropriate brain material properties characteristic of high strain rates observed in blast exposures. To address these limitations, we developed a high-fidelity three-dimensional FE model of a rat head. We explicitly represented the rat’s cerebral vasculature and used high-strain-rate material properties of the rat brain. For a range of blast overpressures (100 to 230 kPa) the brain-pressure predictions matched experimental results and largely overlapped with and tracked the incident pressure–time profile. Incorporating the vasculature decreased the average peak strain in the cerebrum, cerebellum, and brainstem by 17, 33, and 18%, respectively. When compared with our model based on rat-brain properties, the use of human-brain properties in the FE model led to a three-fold reduction in the strain predictions. For simulations of blast exposure in rats, our findings suggest that representing cerebral vasculature and species-specific brain properties has a considerable influence in the resulting brain strain but not the pressure predictions.
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Affiliation(s)
- Ginu Unnikrishnan
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, MCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc (HJF), 6720A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Haojie Mao
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, MCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc (HJF), 6720A Rockledge Drive, Bethesda, MD, 20817, USA
| | - Aravind Sundaramurthy
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, MCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702, USA
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc (HJF), 6720A Rockledge Drive, Bethesda, MD, 20817, USA
| | - E David Bell
- Department of Bioengineering, The University of Utah, 36 S. Wasatch Drive, Salt Lake City, UT, 84112, USA
| | - Stewart Yeoh
- Department of Bioengineering, The University of Utah, 36 S. Wasatch Drive, Salt Lake City, UT, 84112, USA
| | - Kenneth Monson
- Department of Bioengineering, The University of Utah, 36 S. Wasatch Drive, Salt Lake City, UT, 84112, USA
- Department of Mechanical Engineering, The University of Utah, 1495 E 100 S (1550 MEK), Salt Lake City, UT, 84112, USA
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, MCMR-TT, 504 Scott Street, Fort Detrick, MD, 21702, USA.
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