1
|
Sutar S, Ganpule SG. In Silico Investigation of Biomechanical Response of a Human Brain Subjected to Primary Blast. J Biomech Eng 2024; 146:081007. [PMID: 38421339 DOI: 10.1115/1.4064968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 02/23/2024] [Indexed: 03/02/2024]
Abstract
The brain response to the explosion-induced primary blast waves is actively sought. Over the past decade, reasonable progress has been made in the fundamental understanding of blast traumatic brain injury (bTBI) using head surrogates and animal models. Yet, the current understanding of how blast waves interact with human is in nascent stages, primarily due to the lack of data in human. The biomechanical response in human is critically required to faithfully establish the connection to the aforementioned bTBI models. In this work, the biomechanical cascade of the brain under a primary blast has been elucidated using a detailed, full-body human model. The full-body model allowed us to holistically probe short- (<5 ms) and long-term (200 ms) brain responses. The full-body model has been extensively validated against impact loading in the past. We have further validated the head model against blast loading. We have also incorporated the structural anisotropy of the brain white matter. The blast wave transmission, and linear and rotational motion of the head were dominant pathways for the loading of the brain, and these loading paradigms generated distinct biomechanical fields within the brain. Blast transmission and linear motion of the head governed the volumetric response, whereas the rotational motion of the head governed the deviatoric response. Blast induced head rotation alone produced diffuse injury pattern in white matter fiber tracts. The biomechanical response under blast was comparable to the impact event. These insights will augment laboratory and clinical investigations of bTBI and help devise better blast mitigation strategies.
Collapse
Affiliation(s)
- Sunil Sutar
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - S G Ganpule
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| |
Collapse
|
2
|
McLean J, Fereydoonpour M, Ziejewski M, Karami G. Modal Analysis of the Human Brain Using Dynamic Mode Decomposition. Bioengineering (Basel) 2024; 11:604. [PMID: 38927840 PMCID: PMC11200981 DOI: 10.3390/bioengineering11060604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 05/31/2024] [Accepted: 06/08/2024] [Indexed: 06/28/2024] Open
Abstract
The majority of observations and criteria related to brain injuries predominantly focus on acceleration and forces, leaving the understanding of the brain in the frequency domain relatively limited. The impact of an injury can be more profound when considering the brain's resonant frequencies in conjunction with external applied loading and motion. This paper employs a finite element method to conduct an analysis of a human brain under impacts from various angles on the human head. A numerical technique, specifically dynamic mode decomposition (DMD), is utilized to extract modal properties for brain tissue in regions proximate to the corpus callosum and brain stem. Three distinct modal frequencies have been identified, spanning the ranges of 44-68 Hz, 68-155 Hz, and 114-299 Hz. The findings underscore the significance of impact angle, displacement direction, and the specific region of the brain in influencing the modal response of brain tissue during an impact event.
Collapse
Affiliation(s)
| | | | | | - Ghodrat Karami
- Department of Mechanical Engineering, North Dakota State University, Fargo, ND 58102, USA; (J.M.); (M.F.); (M.Z.)
| |
Collapse
|
3
|
Sachdeva T, Ganpule SG. Twenty Years of Blast-Induced Neurotrauma: Current State of Knowledge. Neurotrauma Rep 2024; 5:243-253. [PMID: 38515548 PMCID: PMC10956535 DOI: 10.1089/neur.2024.0001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2024] Open
Abstract
Blast-induced neurotrauma (BINT) is an important injury paradigm of neurotrauma research. This short communication summarizes the current knowledge of BINT. We divide the BINT research into several broad categories-blast wave generation in laboratory, biomechanics, pathology, behavioral outcomes, repetitive blast in animal models, and clinical and neuroimaging investigations in humans. Publications from 2000 to 2023 in each subdomain were considered. The analysis of the literature has brought out salient aspects. Primary blast waves can be simulated reasonably in a laboratory using carefully designed shock tubes. Various biomechanics-based theories of BINT have been proposed; each of these theories may contribute to BINT by generating a unique biomechanical signature. The injury thresholds for BINT are in the nascent stages. Thresholds for rodents are reasonably established, but such thresholds (guided by primary blast data) are unavailable in humans. Single blast exposure animal studies suggest dose-dependent neuronal pathologies predominantly initiated by blood-brain barrier permeability and oxidative stress. The pathologies were typically reversible, with dose-dependent recovery times. Behavioral changes in animals include anxiety, auditory and recognition memory deficits, and fear conditioning. The repetitive blast exposure manifests similar pathologies in animals, however, at lower blast overpressures. White matter irregularities and cortical volume and thickness alterations have been observed in neuroimaging investigations of military personnel exposed to blast. Behavioral changes in human cohorts include sleep disorders, poor motor skills, cognitive dysfunction, depression, and anxiety. Overall, this article provides a concise synopsis of current understanding, consensus, controversies, and potential future directions.
Collapse
Affiliation(s)
- Tarun Sachdeva
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, India
| | - Shailesh G. Ganpule
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, India
- Department of Design, Indian Institute of Technology Roorkee, Roorkee, India
| |
Collapse
|
4
|
Huang A, Cao G. An inverse analysis procedure for characterizing the homogeneous skull model used for predicting blast-induced brain response. Comput Methods Biomech Biomed Engin 2024:1-15. [PMID: 38235754 DOI: 10.1080/10255842.2024.2304286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 01/04/2024] [Indexed: 01/19/2024]
Abstract
Based upon the homogeneous skull model, the skull/brain assembly can be simplified as a homogeneous-shell (HMS)/core structure, in which the exterior shell and interior core represent the skull and brain, respectively. From the blast responses of the spherical shell/core structures calculated via finite element modeling, it is found that the existing homogeneous skull model developed by the well-accepted approach based upon three-point bending tests cannot properly describe the blast response of the skull, modeled as a three-layered sandwich (TLS) shell in the present work, e.g. the average error in the calculated core (brain) pressure is up to ∼30%. Moreover, an innovative approach based upon inverse analysis procedure is then proposed to develop a modified homogeneous skull model, which can give a proper description of the blast response of the skull (a TLS shell), e.g. the average error in the calculated core (brain) pressure is reduced to ∼7%. It is concluded that the well-accepted three-point bending approach cannot develop an effective HMS skull model for studying the blast response of the skull/brain assembly, upon which the model parameter will be overestimated by ∼60%; instead, the innovative approach based upon inverse analysis procedure should be adopted.
Collapse
Affiliation(s)
- An Huang
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, China
| | - Guoxin Cao
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, China
| |
Collapse
|
5
|
Grant KW, Phatak SA, Myers JR, Jenkins KA, Kubli LR, Brungart DS. Functional Hearing Difficulties in Blast-Exposed Service Members With Normal to Near-Normal Hearing Thresholds. Ear Hear 2024; 45:130-141. [PMID: 37599415 DOI: 10.1097/aud.0000000000001407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/22/2023]
Abstract
OBJECTIVES Estimated prevalence of functional hearing and communication deficits (FHCDs), characterized by abnormally low speech recognition and binaural tone detection in noise or an abnormally high degree of self-perceived hearing difficulties, dramatically increases in active-duty service members (SMs) who have hearing thresholds slightly above the normal range and self-report to have been close to an explosive blast. Knowing the exact nature of the underlying auditory-processing deficits that contribute to FHCD would not only provide a better characterization of the effects of blast exposure on the human auditory system, but also allow clinicians to prescribe appropriate therapies to treat or manage patient complaints. DESIGN Two groups of SMs were initially recruited: (1) a control group (N = 78) with auditory thresholds ≤20 dB HL between 250 and 8000 Hz, no history of blast exposure, and who passed a short FHCD screener, and (2) a group of blast-exposed SMs (N = 26) with normal to near-normal auditory thresholds between 250 and 4000 Hz, and who failed the FHCD screener (cutoffs based on the study by Grant et al.). The two groups were then compared on a variety of audiometric, behavioral, cognitive, and electrophysiological measures. These tests were selected to characterize various aspects of auditory system processing from the cochlear to the cortex. A third, smaller group of blast-exposed SMs who performed within normal limits on the FHCD screener were also recruited (N = 11). This third subject group was unplanned at the onset of the study and was added to evaluate the effects of blast exposure on hearing and communication regardless of performance on the FHCD screener. RESULTS SMs in the blast-exposed group with FHCD performed significantly worse than control participants on several metrics that measured peripheral and mostly subcortical auditory processing. Cognitive processing was mostly unaffected by blast exposure with the exception of cognitive tests of language-processing speed and working memory. Blast-exposed SMs without FHCD performed similarly to the control group on tests of peripheral and brainstem processing, but performed similarly to blast-exposed SMs with FHCD on measures of cognitive processing. Measures derived from EEG recordings of the frequency-following response revealed that blast-exposed SMs who exhibited FHCD demonstrated increased spontaneous neural activity, reduced amplitude of the envelope-following response, poor internal signal to noise ratio, reduced response stability, and an absent or delayed onset response, compared with the other two participant groups. CONCLUSIONS Degradation in the neural encoding of acoustic stimuli is likely a major contributing factor leading to FHCD in blast-exposed SMs with normal to near-normal audiometric thresholds. Blast-exposed SMs, regardless of their performance on the FHCD screener, exhibited a deficit in language-processing speed and working memory, which could lead to difficulties in decoding rapid speech and in understanding speech in challenging speech communication settings. Further tests are needed to align these findings with clinical treatment protocols being used for patients with suspected auditory-processing disorders.
Collapse
Affiliation(s)
- Ken W Grant
- Walter Reed National Military Medical Center, Audiology and Speech Pathology Center, Bethesda, Maryland, USA
| | - Sandeep A Phatak
- Walter Reed National Military Medical Center, Audiology and Speech Pathology Center, Bethesda, Maryland, USA
| | - Jennifer R Myers
- Walter Reed National Military Medical Center, Audiology and Speech Pathology Center, Bethesda, Maryland, USA
| | - Kimberly A Jenkins
- Walter Reed National Military Medical Center, Audiology and Speech Pathology Center, Bethesda, Maryland, USA
| | - Lina R Kubli
- Walter Reed National Military Medical Center, Audiology and Speech Pathology Center, Bethesda, Maryland, USA
- U.S. Department of Veterans Affairs, Washington, District of Columbia, USA
| | - Douglas S Brungart
- Walter Reed National Military Medical Center, Audiology and Speech Pathology Center, Bethesda, Maryland, USA
| |
Collapse
|
6
|
Kim SY, Yeh PH, Ollinger JM, Morris HD, Hood MN, Ho VB, Choi KH. Military-related mild traumatic brain injury: clinical characteristics, advanced neuroimaging, and molecular mechanisms. Transl Psychiatry 2023; 13:289. [PMID: 37652994 PMCID: PMC10471788 DOI: 10.1038/s41398-023-02569-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 07/18/2023] [Accepted: 07/24/2023] [Indexed: 09/02/2023] Open
Abstract
Mild traumatic brain injury (mTBI) is a significant health burden among military service members. Although mTBI was once considered relatively benign compared to more severe TBIs, a growing body of evidence has demonstrated the devastating neurological consequences of mTBI, including chronic post-concussion symptoms and deficits in cognition, memory, sleep, vision, and hearing. The discovery of reliable biomarkers for mTBI has been challenging due to under-reporting and heterogeneity of military-related mTBI, unpredictability of pathological changes, and delay of post-injury clinical evaluations. Moreover, compared to more severe TBI, mTBI is especially difficult to diagnose due to the lack of overt clinical neuroimaging findings. Yet, advanced neuroimaging techniques using magnetic resonance imaging (MRI) hold promise in detecting microstructural aberrations following mTBI. Using different pulse sequences, MRI enables the evaluation of different tissue characteristics without risks associated with ionizing radiation inherent to other imaging modalities, such as X-ray-based studies or computerized tomography (CT). Accordingly, considering the high morbidity of mTBI in military populations, debilitating post-injury symptoms, and lack of robust neuroimaging biomarkers, this review (1) summarizes the nature and mechanisms of mTBI in military settings, (2) describes clinical characteristics of military-related mTBI and associated comorbidities, such as post-traumatic stress disorder (PTSD), (3) highlights advanced neuroimaging techniques used to study mTBI and the molecular mechanisms that can be inferred, and (4) discusses emerging frontiers in advanced neuroimaging for mTBI. We encourage multi-modal approaches combining neuropsychiatric, blood-based, and genetic data as well as the discovery and employment of new imaging techniques with big data analytics that enable accurate detection of post-injury pathologic aberrations related to tissue microstructure, glymphatic function, and neurodegeneration. Ultimately, this review provides a foundational overview of military-related mTBI and advanced neuroimaging techniques that merit further study for mTBI diagnosis, prognosis, and treatment monitoring.
Collapse
Affiliation(s)
- Sharon Y Kim
- School of Medicine, Uniformed Services University, Bethesda, MD, USA
- Program in Neuroscience, Uniformed Services University, Bethesda, MD, USA
| | - Ping-Hong Yeh
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - John M Ollinger
- Program in Neuroscience, Uniformed Services University, Bethesda, MD, USA
- National Intrepid Center of Excellence, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Herman D Morris
- Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD, USA
- Department of Radiology, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Maureen N Hood
- Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD, USA
- Department of Radiology, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Vincent B Ho
- Department of Radiology and Radiological Sciences, Uniformed Services University, Bethesda, MD, USA
- Department of Radiology, Walter Reed National Military Medical Center, Bethesda, MD, USA
| | - Kwang H Choi
- Program in Neuroscience, Uniformed Services University, Bethesda, MD, USA.
- Center for the Study of Traumatic Stress, Uniformed Services University, Bethesda, MD, USA.
- Department of Psychiatry, Uniformed Services University, Bethesda, MD, USA.
| |
Collapse
|
7
|
Muresanu DF, Sharma A, Tian ZR, Lafuente JV, Nozari A, Feng L, Buzoianu AD, Wiklund L, Sharma HS. Nanowired Delivery of Cerebrolysin with Mesenchymal Stem Cells Attenuates Heat Stress-Induced Exacerbation of Neuropathology Following Brain Blast Injury. ADVANCES IN NEUROBIOLOGY 2023; 32:231-270. [PMID: 37480463 DOI: 10.1007/978-3-031-32997-5_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2023]
Abstract
Blast brain injury (bBI) following explosive detonations in warfare is one of the prominent causes of multidimensional insults to the central nervous and other vital organs injury. Several military personnel suffered from bBI during the Middle East conflict at hot environment. The bBI largely occurs due to pressure waves, generation of heat together with release of shrapnel and gun powders explosion with penetrating and/or impact head trauma causing multiple brain damage. As a result, bBI-induced secondary injury causes breakdown of the blood-brain barrier (BBB) and edema formation that further results in neuronal, glial and axonal injuries. Previously, we reported endocrine imbalance and influence of diabetes on bBI-induced brain pathology that was significantly attenuated by nanowired delivery of cerebrolysin in model experiments. Cerebrolysin is a balanced composition of several neurotrophic factors, and active peptide fragment is capable of neuroprotection in several neurological insults. Exposure to heat stress alone causes BBB damage, edema formation and brain pathology. Thus, it is quite likely that hot environment further exacerbates the consequences of bBI. Thus, novel therapeutic strategies using nanodelivery of stem cell and cerebrolysin may further enhance superior neuroprotection in bBI at hot environment. Our observations are the first to show that combined nanowired delivery of mesenchymal stem cells (MSCs) and cerebrolysin significantly attenuated exacerbation of bBI in hot environment and induced superior neuroprotection, not reported earlier. The possible mechanisms of neuroprotection with MSCs and cerebrolysin in bBI are discussed in the light of current literature.
Collapse
Affiliation(s)
- Dafin F Muresanu
- Department of Clinical Neurosciences, University of Medicine & Pharmacy, Cluj-Napoca, Romania
- "RoNeuro" Institute for Neurological Research and Diagnostic, Cluj-Napoca, Romania
| | - Aruna Sharma
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden
| | - Z Ryan Tian
- Department of Chemistry & Biochemistry, University of Arkansas, Fayetteville, AR, USA
| | - José Vicente Lafuente
- LaNCE, Department of Neuroscience, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain
| | - Ala Nozari
- Anesthesiology & Intensive Care, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA, USA
| | - Lianyuan Feng
- Department of Neurology, Bethune International Peace Hospital, Zhongshan, Hebei Province, China
| | - Anca D Buzoianu
- Department of Clinical Pharmacology and Toxicology, "Iuliu Hatieganu" University of Medicine and Pharmacy, Cluj-Napoca, Romania
| | - Lars Wiklund
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden
| | - Hari Shanker Sharma
- International Experimental Central Nervous System Injury & Repair (IECNSIR), Department of Surgical Sciences, Anesthesiology & Intensive Care Medicine, Uppsala University Hospital, Uppsala University, Uppsala, Sweden.
| |
Collapse
|
8
|
Bennion NJ, Zappalá S, Potts M, Woolley M, Marshall D, Evans SL. In vivo measurement of human brain material properties under quasi-static loading. J R Soc Interface 2022; 19:20220557. [PMID: 36514891 PMCID: PMC9748497 DOI: 10.1098/rsif.2022.0557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Computational modelling of the brain requires accurate representation of the tissues concerned. Mechanical testing has numerous challenges, in particular for low strain rates, like neurosurgery, where redistribution of fluid is biomechanically important. A finite-element (FE) model was generated in FEBio, incorporating a spring element/fluid-structure interaction representation of the pia-arachnoid complex (PAC). The model was loaded to represent gravity in prone and supine positions. Material parameter identification and sensitivity analysis were performed using statistical software, comparing the FE results to human in vivo measurements. Results for the brain Ogden parameters µ, α and k yielded values of 670 Pa, -19 and 148 kPa, supporting values reported in the literature. Values of the order of 1.2 MPa and 7.7 kPa were obtained for stiffness of the pia mater and out-of-plane tensile stiffness of the PAC, respectively. Positional brain shift was found to be non-rigid and largely driven by redistribution of fluid within the tissue. To the best of our knowledge, this is the first study using in vivo human data and gravitational loading in order to estimate the material properties of intracranial tissues. This model could now be applied to reduce the impact of positional brain shift in stereotactic neurosurgery.
Collapse
Affiliation(s)
| | - Stefano Zappalá
- School of Computer Science and Informatics, Cardiff University, Cardiff CF24 3AA, UK,Cardiff University Brain Research Imaging Centre (CUBRIC), School of Psychology, Cardiff University, Cardiff CF24 4HQ, UK
| | - Matthew Potts
- School of Engineering, Cardiff University, Cardiff CF10 3AT, UK
| | - Max Woolley
- Functional Neurosurgery Research Group, School of Clinical Sciences, University of Bristol, Bristol, UK,Renishaw Neuro Solutions Ltd, Wotton Road, Wotton-under-Edge GL12 8SP, UK
| | - David Marshall
- School of Computer Science and Informatics, Cardiff University, Cardiff CF24 3AA, UK
| | - Sam L. Evans
- School of Engineering, Cardiff University, Cardiff CF10 3AT, UK
| |
Collapse
|
9
|
Hasan F, Mahmud KAHA, Khan MI, Adnan A. Viscoelastic damage evaluation of the axon. Front Bioeng Biotechnol 2022; 10:904818. [PMID: 36277388 PMCID: PMC9583024 DOI: 10.3389/fbioe.2022.904818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
In this manuscript, we have studied the microstructure of the axonal cytoskeleton and adopted a bottom-up approach to evaluate the mechanical responses of axons. The cytoskeleton of the axon includes the microtubules (MT), Tau proteins (Tau), neurofilaments (NF), and microfilaments (MF). Although most of the rigidity of the axons is due to the MT, the viscoelastic response of axons comes from the Tau. Early studies have shown that NF and MF do not provide significant elasticity to the overall response of axons. Therefore, the most critical aspect of the mechanical response of axons is the microstructural topology of how MT and Tau are connected and construct the cross-linked network. Using a scanning electron microscope (SEM), the cross-sectional view of the axons revealed that the MTs are organized in a hexagonal array and cross-linked by Tau. Therefore, we have developed a hexagonal Representative Volume Element (RVE) of the axonal microstructure with MT and Tau as fibers. The matrix of the RVE is modeled by considering a combined effect of NF and MF. A parametric study is done by varying fiber geometric and mechanical properties. The Young’s modulus and spacing of MT are varied between 1.5 and 1.9 GPa and 20–38 nm, respectively. Tau is modeled as a 3-parameter General Maxwell viscoelastic material. The failure strains for MT and Tau are taken to be 50 and 40%, respectively. A total of 4 RVEs are prepared for finite element analysis, and six loading cases are inspected to quantify the three-dimensional (3D) viscoelastic relaxation response. The volume-averaged stress and strain are then used to fit the relaxation Prony series. Next, we imposed varying strain rates (between 10/sec to 50/sec) on the RVE and analyzed the axonal failure process. We have observed that the 40% failure strain of Tau is achieved in all strain rates before the MT reaches its failure strain of 50%. The corresponding axonal failure strain and stress vary between 6 and 11% and 5–19.8 MPa, respectively. This study can be used to model macroscale axonal aggregate typical of the white matter region of the brain tissue.
Collapse
Affiliation(s)
- Fuad Hasan
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX, United States
| | - KAH Al Mahmud
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX, United States
| | - Md. Ishak Khan
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ashfaq Adnan
- Department of Mechanical and Aerospace Engineering, The University of Texas at Arlington, Arlington, TX, United States
- *Correspondence: Ashfaq Adnan,
| |
Collapse
|
10
|
Du Z, Li Z, Wang P, Wang X, Zhang J, Zhuang Z, Liu Z. Revealing the Effect of Skull Deformation on Intracranial Pressure Variation During the Direct Interaction Between Blast Wave and Surrogate Head. Ann Biomed Eng 2022; 50:1038-1052. [PMID: 35668281 DOI: 10.1007/s10439-022-02982-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 05/13/2022] [Indexed: 11/01/2022]
Abstract
Intracranial pressure (ICP) during the interaction between blast wave and the head is a crucial evaluation criterion for blast-induced traumatic brain injury (bTBI). ICP variation is mainly induced by the blast wave transmission and skull deformation. However, how the skull deformation influences the ICP remains unclear, which is meaningful for mitigating bTBI. In this study, both experimental and numerical models are developed to elucidate the effect of skull deformation on ICP variation. Firstly, we performed the shock tube experiment of the high-fidelity surrogate head to measure the ICP, the blast overpressure, and the skull surface strain of specific positions. The results show that the ICP profiles of all measured points show oscillations with positive and negative change, and the variation is consistent with the skull surface strain. Further numerical analysis reveals that when the blast wave reaches the measured point, the peak overpressure transmits directly through the skull to the brain, forming the local positive ICP peak, and the impulse induces the local inward deformation of the skull. As the peak overpressure passes through, the blast impulse impacts the nearby skull supported by the soft and incompressible brain tissue and extrudes the skull outward in the initial position. The inward and outward skull deformation leads to the oscillation of ICP. These numerical analyses agree with experimental results, which explain the appearance of negative and positive ICP peaks and the synchronization of negative ICP with surface strain. The study has implications for medical injury diagnosis and protective equipment design.
Collapse
Affiliation(s)
- Zhibo Du
- School of Aerospace Engineering, Tsinghua University, Beijing, 100084, P.R. China
| | - Zhijie Li
- School of Aerospace Engineering, Tsinghua University, Beijing, 100084, P.R. China
| | - Peng Wang
- School of Aerospace Engineering, Tsinghua University, Beijing, 100084, P.R. China
| | - Xinghao Wang
- School of Aerospace Engineering, Tsinghua University, Beijing, 100084, P.R. China
| | - Jiarui Zhang
- School of Aerospace Engineering, Tsinghua University, Beijing, 100084, P.R. China
| | - Zhuo Zhuang
- School of Aerospace Engineering, Tsinghua University, Beijing, 100084, P.R. China
| | - Zhanli Liu
- School of Aerospace Engineering, Tsinghua University, Beijing, 100084, P.R. China.
| |
Collapse
|
11
|
Liu Y, Lu Y, Shao Y, Wu Y, He J, Wu C. Mechanism of the traumatic brain injury induced by blast wave using the energy assessment method. Med Eng Phys 2022; 101:103767. [DOI: 10.1016/j.medengphy.2022.103767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/20/2022] [Accepted: 02/06/2022] [Indexed: 11/26/2022]
|
12
|
Subramaniam DR, Unnikrishnan G, Sundaramurthy A, Rubio JE, Kote VB, Reifman J. Cerebral Vasculature Influences Blast-Induced Biomechanical Responses of Human Brain Tissue. Front Bioeng Biotechnol 2021; 9:744808. [PMID: 34805106 PMCID: PMC8599150 DOI: 10.3389/fbioe.2021.744808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 10/18/2021] [Indexed: 11/13/2022] Open
Abstract
Multiple finite-element (FE) models to predict the biomechanical responses in the human brain resulting from the interaction with blast waves have established the importance of including the brain-surface convolutions, the major cerebral veins, and using non-linear brain-tissue properties to improve model accuracy. We hypothesize that inclusion of a more detailed network of cerebral veins and arteries can further enhance the model-predicted biomechanical responses and help identify correlates of blast-induced brain injury. To more comprehensively capture the biomechanical responses of human brain tissues to blast-wave exposure, we coupled a three-dimensional (3-D) detailed-vasculature human-head FE model, previously validated for blunt impact, with a 3-D shock-tube FE model. Using the coupled model, we computed the biomechanical responses of a human head facing an incoming blast wave for blast overpressures (BOPs) equivalent to 68, 83, and 104 kPa. We validated our FE model, which includes the detailed network of cerebral veins and arteries, the gyri and the sulci, and hyper-viscoelastic brain-tissue properties, by comparing the model-predicted intracranial pressure (ICP) values with previously collected data from shock-tube experiments performed on cadaver heads. In addition, to quantify the influence of including a more comprehensive network of brain vessels, we compared the biomechanical responses of our detailed-vasculature model with those of a reduced-vasculature model and a no-vasculature model for the same blast-loading conditions. For the three BOPs, the predicted ICP values matched well with the experimental results in the frontal lobe, with peak-pressure differences of 4-11% and phase-shift differences of 9-13%. As expected, incorporating the detailed cerebral vasculature did not influence the ICP, however, it redistributed the peak brain-tissue strains by as much as 30% and yielded peak strain differences of up to 7%. When compared to existing reduced-vasculature FE models that only include the major cerebral veins, our high-fidelity model redistributed the brain-tissue strains in most of the brain, highlighting the importance of including a detailed cerebral vessel network in human-head FE models to more comprehensively account for the biomechanical responses induced by blast exposure.
Collapse
Affiliation(s)
- 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, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - 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, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - 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, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - 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, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - Vivek Bhaskar Kote
- 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, United States
- The Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc., Bethesda, MD, United States
| | - 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, United States
| |
Collapse
|
13
|
Estimated Prevalence of Functional Hearing Difficulties in Blast-Exposed Service Members With Normal to Near-Normal-Hearing Thresholds. Ear Hear 2021; 42:1615-1626. [PMID: 34108398 DOI: 10.1097/aud.0000000000001067] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Over the past decade, U.S. Department of Defense and Veterans Affairs audiologists have reported large numbers of relatively young adult patients who have normal to near-normal audiometric thresholds but who report difficulty understanding speech in noisy environments. Many of these service members also reported having experienced exposure to explosive blasts as part of their military service. Recent studies suggest that some blast-exposed patients with normal to near-normal-hearing thresholds not only have an awareness of increased hearing difficulties, but also poor performance on various auditory tasks (sound source localization, speech recognition in noise, binaural integration, gap detection in noise, etc.). The purpose of this study was to determine the prevalence of functional hearing and communication deficits (FHCD) among healthy Active-Duty service men and women with normal to near-normal audiometric thresholds. DESIGN To estimate the prevalence of such FHCD in the overall military population, performance of roughly 3400 Active-Duty service members with hearing thresholds mostly within the normal range were measured on 4 hearing tests and a brief 6-question survey to assess FHCD. Subjects were subdivided into 6 groups depending on the severity of the blast exposure (3 levels: none, far away, or close enough to feel heat or pressure) and hearing thresholds (2 levels: audiometric thresholds of 20 dB HL or better, slight elevation in 1 or more thresholds between 500 and 4000 Hz in either ear). RESULTS While the probability of having hearing difficulty was low (≈4.2%) for the overall population tested, that probability increased by 2 to 3 times if the service member was blast-exposed from a close distance or had slightly elevated hearing thresholds (>20 dB HL). Service members having both blast exposure and mildly elevated hearing thresholds exhibited up to 4 times higher risk for performing abnormally on auditory tasks and more than 5 times higher risk for reporting abnormally low ratings on the subjective questionnaire, compared with service members with no history of blast exposure and audiometric thresholds ≤20 dB HL. Blast-exposed listeners were roughly 2.5 times more likely to experience subjective or objective hearing deficits than those with no-blast history. CONCLUSIONS These elevated rates of abnormal performance suggest that roughly 33.6% of Active-Duty service members (or approximately 423,000) with normal to near-normal-hearing thresholds (i.e., H1 profile) are at some risk for FHCD, and about 5.7% (approximately 72,000) are at high risk, but are currently untested and undetected within the current fitness-for-duty standards. Service members identified as "at risk" for FHCD according to the metrics used in the present study, in spite of their excellent hearing thresholds, require further testing to determine whether they have sustained damage to peripheral and early-stage auditory processing (bottom-up processing), damage to cognitive processes for speech (top-down processing), or both. Understanding the extent of damage due to noise and blast exposures and the balance between bottom-up processing deficits and top-down deficits will likely lead to better therapeutic strategies.
Collapse
|
14
|
Sundar S, Ponnalagu A. Biomechanical Analysis of Head Subjected to Blast Waves and the Role of Combat Protective Headgear Under Blast Loading: A Review. J Biomech Eng 2021; 143:100801. [PMID: 33954580 DOI: 10.1115/1.4051047] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Indexed: 01/10/2023]
Abstract
Blast-induced traumatic brain injury (bTBI) is a rising health concern of soldiers deployed in modern-day military conflicts. For bTBI, blast wave loading is a cause, and damage incurred to brain tissue is the effect. There are several proposed mechanisms for the bTBI, such as direct cranial entry, skull flexure, thoracic compression, blast-induced acceleration, and cavitation that are not mutually exclusive. So the cause-effect relationship is not straightforward. The efficiency of protective headgears against blast waves is relatively unknown as compared with other threats. Proper knowledge about standard problem space, underlying mechanisms, blast reconstruction techniques, and biomechanical models are essential for protective headgear design and evaluation. Various researchers from cross disciplines analyze bTBI from different perspectives. From the biomedical perspective, the physiological response, neuropathology, injury scales, and even the molecular level and cellular level changes incurred during injury are essential. From a combat protective gear designer perspective, the spatial and temporal variation of mechanical correlates of brain injury such as surface overpressure, acceleration, tissue-level stresses, and strains are essential. This paper outlines the key inferences from bTBI studies that are essential in the protective headgear design context.
Collapse
Affiliation(s)
- Shyam Sundar
- Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| | - Alagappan Ponnalagu
- Department of Civil Engineering, Indian Institute of Technology Madras, Chennai 600036, India
| |
Collapse
|
15
|
Taddei L, Bracq A, Delille R, Bourel B, Marechal C, Lauro F, Roth S. Effect of blast loading on the risk of rib fractures: a preliminary 3D numerical investigation. Forensic Sci Int 2021; 326:110930. [PMID: 34332264 DOI: 10.1016/j.forsciint.2021.110930] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 06/23/2021] [Accepted: 07/19/2021] [Indexed: 11/16/2022]
Abstract
Blast is a complex phenomenon which needs to be understood, especially in a military framework, where this kind of loading can have severe consequences on the human body. Indeed, the literature lists a number of studies which try to investigate the dangerousness of such a phenomenon, both at experimental and numerical level, and the injuries that could occur when the fighters or police officers are stroke by blast wave. When focusing on primary blast effect, this paper analyses the effect of this loading on the occurrence of rib fracture, using previously developed injury risk curves.
Collapse
Affiliation(s)
- Lorenzo Taddei
- Laboratoire Interdisciplinaire Carnot de Bourgogne, site UTBM, UMR CNRS 6303/Univ. Bourgogne Franche-Comte (UBFC), Belfort, France
| | - Anthony Bracq
- Laboratory LAMIH UMR 8201 CNRS, Univ. Polytechnique Hauts-de-France, 59313 Valenciennes, France
| | - Remi Delille
- Laboratory LAMIH UMR 8201 CNRS, Univ. Polytechnique Hauts-de-France, 59313 Valenciennes, France
| | - Benjamin Bourel
- Laboratory LAMIH UMR 8201 CNRS, Univ. Polytechnique Hauts-de-France, 59313 Valenciennes, France
| | - Christophe Marechal
- Laboratory LAMIH UMR 8201 CNRS, Univ. Polytechnique Hauts-de-France, 59313 Valenciennes, France
| | - Franck Lauro
- Laboratory LAMIH UMR 8201 CNRS, Univ. Polytechnique Hauts-de-France, 59313 Valenciennes, France
| | - Sebastien Roth
- Laboratoire Interdisciplinaire Carnot de Bourgogne, site UTBM, UMR CNRS 6303/Univ. Bourgogne Franche-Comte (UBFC), Belfort, France.
| |
Collapse
|
16
|
Miller ST, Cooper CF, Elsbernd P, Kerwin J, Mejia-Alvarez R, Willis AM. Localizing Clinical Patterns of Blast Traumatic Brain Injury Through Computational Modeling and Simulation. Front Neurol 2021; 12:547655. [PMID: 34093380 PMCID: PMC8173077 DOI: 10.3389/fneur.2021.547655] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 03/10/2021] [Indexed: 11/13/2022] Open
Abstract
Blast traumatic brain injury is ubiquitous in modern military conflict with significant morbidity and mortality. Yet the mechanism by which blast overpressure waves cause specific intracranial injury in humans remains unclear. Reviewing of both the clinical experience of neurointensivists and neurosurgeons who treated service members exposed to blast have revealed a pattern of injury to cerebral blood vessels, manifested as subarachnoid hemorrhage, pseudoaneurysm, and early diffuse cerebral edema. Additionally, a seminal neuropathologic case series of victims of blast traumatic brain injury (TBI) showed unique astroglial scarring patterns at the following tissue interfaces: subpial glial plate, perivascular, periventricular, and cerebral gray-white interface. The uniting feature of both the clinical and neuropathologic findings in blast TBI is the co-location of injury to material interfaces, be it solid-fluid or solid-solid interface. This motivates the hypothesis that blast TBI is an injury at the intracranial mechanical interfaces. In order to investigate the intracranial interface dynamics, we performed a novel set of computational simulations using a model human head simplified but containing models of gyri, sulci, cerebrospinal fluid (CSF), ventricles, and vasculature with high spatial resolution of the mechanical interfaces. Simulations were performed within a hybrid Eulerian—Lagrangian simulation suite (CTH coupled via Zapotec to Sierra Mechanics). Because of the large computational meshes, simulations required high performance computing resources. Twenty simulations were performed across multiple exposure scenarios—overpressures of 150, 250, and 500 kPa with 1 ms overpressure durations—for multiple blast exposures (front blast, side blast, and wall blast) across large variations in material model parameters (brain shear properties, skull elastic moduli). All simulations predict fluid cavitation within CSF (where intracerebral vasculature reside) with cavitation occurring deep and diffusely into cerebral sulci. These cavitation events are adjacent to high interface strain rates at the subpial glial plate. Larger overpressure simulations (250 and 500kPa) demonstrated intraventricular cavitation—also associated with adjacent high periventricular strain rates. Additionally, models of embedded intraparenchymal vascular structures—with diameters as small as 0.6 mm—predicted intravascular cavitation with adjacent high perivascular strain rates. The co-location of local maxima of strain rates near several of the regions that appear to be preferentially damaged in blast TBI (vascular structures, subpial glial plate, perivascular regions, and periventricular regions) suggest that intracranial interface dynamics may be important in understanding how blast overpressures leads to intracranial injury.
Collapse
Affiliation(s)
- Scott T Miller
- Computational Solid Mechanics & Structural Dynamics, Sandia National Laboratories, Albuquerque, NM, United States
| | - Candice F Cooper
- Terminal Ballistics Technology, Sandia National Laboratories, Albuquerque, NM, United States
| | - Paul Elsbernd
- Department of Neurology, Brooke Army Medical Center, Fort Sam Houston, TX, United States
| | - Joseph Kerwin
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States
| | - Ricardo Mejia-Alvarez
- Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States
| | - Adam M Willis
- Department of Neurology, Brooke Army Medical Center, Fort Sam Houston, TX, United States.,Department of Mechanical Engineering, Michigan State University, East Lansing, MI, United States
| |
Collapse
|
17
|
Zhang L, Jackson WJ, Bentil SA. Deformation of an airfoil-shaped brain surrogate under shock wave loading. J Mech Behav Biomed Mater 2021; 120:104513. [PMID: 34010798 DOI: 10.1016/j.jmbbm.2021.104513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 03/30/2021] [Accepted: 04/07/2021] [Indexed: 10/21/2022]
Abstract
Improvised explosive devices (IEDs), during military operations, has increased the incidence of blast-induced traumatic brain injuries (bTBI). The shock wave is created following detonation of the IED. This shock wave propagates through the atmosphere and may cause bTBI. As a result, bTBI research has gained increased attention since this injury's mechanism is not thoroughly understood. To develop better protection and treatment against bTBI, further studies of soft material (e.g. brain and brain surrogate) deformation due to shock wave exposure are essential. However, the dynamic mechanical behavior of soft materials, subjected to high strain rates from shock wave exposure, remains unknown. Thus, an experimental approach was applied to study the interaction between the shock wave and an unconfined brain surrogate fabricated from a biomaterial (i.e. polydimethylsiloxane (PDMS)). The 1:70 ratio of curing agent-to-base determined the stiffness of the PDMS (Sylgard 184, Dow Corning Corporation). A stretched NACA 2414 (upper airfoil surface) geometry was utilized to resemble the shape of a porcine brain. Digital image correlation (DIC) technique was applied to measure the deformation on the brain surrogate's surface following shock wave exposure. A shock tube was utilized to create the shock wave and pressure transducers measured the pressure in the vicinity of the brain surrogate. A transient structural analysis using ANSYS Workbench was performed to predict the elastic modulus of 1:70 airfoil-shaped PDMS, at a strain rate on the order of 6 × 103 s-1. Both compression and protrusion of the PDMS surface were found due to the shock wave exposure. Negative pressure was found in a semi-ring area, which was the cause of protrusion. Oscillation of the brain surrogate, due to the shock wave loading, was found. The frequency of oscillation does not depend on the geometry. This work will add to the limited data describing the dynamic behavior of soft materials due to shock wave loading.
Collapse
Affiliation(s)
- Ling Zhang
- Department of Mechanical Engineering, Iowa State University of Science and Technology, 2529 Union Drive, Ames, IA, 50011, USA
| | - William J Jackson
- Department of Mechanical Engineering, Iowa State University of Science and Technology, 2529 Union Drive, Ames, IA, 50011, USA
| | - Sarah A Bentil
- Department of Mechanical Engineering, Iowa State University of Science and Technology, 2529 Union Drive, Ames, IA, 50011, USA.
| |
Collapse
|
18
|
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; 143:051007. [PMID: 33493319 DOI: 10.1115/1.4049889] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [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.
Collapse
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
| |
Collapse
|
19
|
Wang Y, Urioste RT, Wei Y, Wilder DM, Arun P, Sajja V, Gist ID, Fitzgerald TS, Chang W, Kelley MW, Long JB. Blast-induced hearing impairment in rats is associated with structural and molecular changes of the inner ear. Sci Rep 2020; 10:10652. [PMID: 32606369 PMCID: PMC7327022 DOI: 10.1038/s41598-020-67389-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 04/29/2020] [Indexed: 02/08/2023] Open
Abstract
Auditory dysfunction is the most prevalent injury associated with blast overpressure exposure (BOP) in Warfighters and civilians, yet little is known about the underlying pathophysiological mechanisms. To gain insights into these injuries, an advanced blast simulator was used to expose rats to BOP and assessments were made to identify structural and molecular changes in the middle/inner ears utilizing otoscopy, RNA sequencing (RNA-seq), and histopathological analysis. Deficits persisting up to 1 month after blast exposure were observed in the distortion product otoacoustic emissions (DPOAEs) and the auditory brainstem responses (ABRs) across the entire range of tested frequencies (4–40 kHz). During the recovery phase at sub-acute time points, low frequency (e.g. 4–8 kHz) hearing improved relatively earlier than for high frequency (e.g. 32–40 kHz). Perforation of tympanic membranes and middle ear hemorrhage were observed at 1 and 7 days, and were restored by day 28 post-blast. A total of 1,158 differentially expressed genes (DEGs) were significantly altered in the cochlea on day 1 (40% up-regulated and 60% down-regulated), whereas only 49 DEGs were identified on day 28 (63% up-regulated and 37% down-regulated). Seven common DEGs were identified at both days 1 and 28 following blast, and are associated with inner ear mechanotransduction, cytoskeletal reorganization, myelin development and axon survival. Further studies on altered gene expression in the blast-injured rat cochlea may provide insights into new therapeutic targets and approaches to prevent or treat similar cases of blast-induced auditory damage in human subjects.
Collapse
Affiliation(s)
- Ying Wang
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA.
| | - Rodrigo T Urioste
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA
| | - Yanling Wei
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA
| | - Donna M Wilder
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA
| | - Peethambaran Arun
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA
| | - Venkatasivasaisujith Sajja
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA
| | - Irene D Gist
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA
| | | | - Weise Chang
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, MD, USA
| | - Matthew W Kelley
- Section on Developmental Neuroscience, National Institute on Deafness and Other Communication Disorders (NIDCD), Bethesda, MD, USA
| | - Joseph B Long
- Blast-Induced Neurotrauma Branch, Center for Military Psychiatry and Neuroscience, Walter Reed Army Institute of Research, Bethesda, MD, USA.
| |
Collapse
|
20
|
Losurdo M, Davidsson J, Sköld MK. Diffuse Axonal Injury in the Rat Brain: Axonal Injury and Oligodendrocyte Activity Following Rotational Injury. Brain Sci 2020; 10:E229. [PMID: 32290212 PMCID: PMC7225974 DOI: 10.3390/brainsci10040229] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/03/2020] [Accepted: 04/07/2020] [Indexed: 02/06/2023] Open
Abstract
Traumatic brain injury (TBI) commonly results in primary diffuse axonal injury (DAI) and associated secondary injuries that evolve through a cascade of pathological mechanisms. We aim at assessing how myelin and oligodendrocytes react to head angular-acceleration-induced TBI in a previously described model. This model induces axonal injuries visible by amyloid precursor protein (APP) expression, predominantly in the corpus callosum and its borders. Brain tissue from a total of 27 adult rats was collected at 24 h, 72 h and 7 d post-injury. Coronal sections were prepared for immunohistochemistry and RNAscope® to investigate DAI and myelin changes (APP, MBP, Rip), oligodendrocyte lineage cell loss (Olig2), oligodendrocyte progenitor cells (OPCs) (NG2, PDGFRa) and neuronal stress (HSP70, ATF3). Oligodendrocytes and OPCs numbers (expressed as percentage of positive cells out of total number of cells) were measured in areas with high APP expression. Results showed non-statistically significant trends with a decrease in oligodendrocyte lineage cells and an increase in OPCs. Levels of myelination were mostly unaltered, although Rip expression differed significantly between sham and injured animals in the frontal brain. Neuronal stress markers were induced at the dorsal cortex and habenular nuclei. We conclude that rotational injury induces DAI and neuronal stress in specific areas. We noticed indications of oligodendrocyte death and regeneration without statistically significant changes at the timepoints measured, despite indications of axonal injuries and neuronal stress. This might suggest that oligodendrocytes are robust enough to withstand this kind of trauma, knowledge important for the understanding of thresholds for cell injury and post-traumatic recovery potential.
Collapse
Affiliation(s)
- Michela Losurdo
- Department of Neuroscience, Karolinska Institute, 171 77 Stockholm, Sweden;
- Department of Molecular Medicine, Università degli Studi di Pavia, 27100 Pavia, Italy
| | - Johan Davidsson
- Department of Mechanics and Maritime Sciences, Chalmers University of Technology, 412 96 Gothenburg, Sweden;
| | - Mattias K. Sköld
- Department of Neuroscience, Karolinska Institute, 171 77 Stockholm, Sweden;
- Department of Neuroscience, Section of Neurosurgery, Uppsala University, 751 85 Uppsala, Sweden
| |
Collapse
|
21
|
The Strain Rates in the Brain, Brainstem, Dura, and Skull under Dynamic Loadings. MATHEMATICAL AND COMPUTATIONAL APPLICATIONS 2020. [DOI: 10.3390/mca25020021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Knowing the precise material properties of intracranial head organs is crucial for studying the biomechanics of head injury. It has been shown that these biological tissues are significantly rate-dependent; hence, their material properties should be determined with respect to the range of deformation rate they experience. In this paper, a validated finite element human head model is used to investigate the biomechanics of the head in impact and blast, leading to traumatic brain injuries (TBI). We simulate the head under various directions and velocities of impacts, as well as helmeted and unhelmeted head under blast shock waves. It is demonstrated that the strain rates for the brain are in the range of 36 to 241 s−1, approximately 1.9 and 0.86 times the resulting head acceleration under impacts and blast scenarios, respectively. The skull was found to experience a rate in the range of 14 to 182 s−1, approximately 0.7 and 0.43 times the head acceleration corresponding to impact and blast cases. The results of these incident simulations indicate that the strain rates for brainstem and dura mater are respectively in the range of 15 to 338 and 8 to 149 s−1. These findings provide a good insight into characterizing the brain tissue, cranial bone, brainstem and dura mater, and also selecting material properties in advance for computational dynamical studies of the human head.
Collapse
|
22
|
Hoursan H, Farahmand F, Ahmadian MT. A Three-Dimensional Statistical Volume Element for Histology Informed Micromechanical Modeling of Brain White Matter. Ann Biomed Eng 2020; 48:1337-1353. [PMID: 31965358 DOI: 10.1007/s10439-020-02458-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 01/11/2020] [Indexed: 02/02/2023]
Abstract
This study presents a novel statistical volume element (SVE) for micromechanical modeling of the white matter structures, with histology-informed randomized distribution of axonal tracts within the extracellular matrix. The model was constructed based on the probability distribution functions obtained from the results of diffusion tensor imaging as well as the histological observations of scanning electron micrograph, at two structures of white matter susceptible to traumatic brain injury, i.e. corpus callosum and corona radiata. A simplistic representative volume element (RVE) with symmetrical arrangement of fully alligned axonal fibers was also created as a reference for comparison. A parametric study was conducted to find the optimum grid and edge size which ensured the periodicity and ergodicity of the SVE and RVE models. A multi-objective evolutionary optimization procedure was used to find the hyperelastic and viscoelastic material constants of the constituents, based on the experimentally reported responses of corpus callosum to axonal and transverse loadings. The optimal material properties were then used to predict the homogenized and localized responses of corpus callosum and corona radiata. The results indicated similar homogenized responses of the SVE and RVE under quasi-static extension, which were in good agreement with the experimental data. Under shear strain, however, the models exhibited different behaviors, with the SVE model showing much closer response to the experimental observations. Moreover, the SVE model displayed a significantly better agreement with the reports of the experiments at high strain rates. The results suggest that the randomized fiber architecture has a great influence on the validity of the micromechanical models of white matter, with a distinguished impact on the model's response to shear deformation and high strain rates. Moreover, it can provide a more detailed presentation of the localized responses of the tissue substructures, including the stress concentrations around the low caliber axonal tracts, which is critical for studying the axonal injury mechanisms.
Collapse
Affiliation(s)
- Hesam Hoursan
- Mechanical Engineering Department, Sharif University of Technology, Tehran, Iran
| | - Farzam Farahmand
- Mechanical Engineering Department, Sharif University of Technology, Tehran, Iran.
- RCBTR, Tehran University of Medical Sciences, Tehran, Iran.
| | | |
Collapse
|
23
|
Bing Y, Garcia-Gonzalez D, Voets N, Jérusalem A. Medical imaging based in silico head model for ischaemic stroke simulation. J Mech Behav Biomed Mater 2020; 101:103442. [DOI: 10.1016/j.jmbbm.2019.103442] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 09/03/2019] [Accepted: 09/18/2019] [Indexed: 12/15/2022]
|
24
|
Yu X, Ghajari M. An assessment of blast modelling techniques for injury biomechanics research. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2019; 35:e3258. [PMID: 31518061 DOI: 10.1002/cnm.3258] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/06/2019] [Accepted: 09/01/2019] [Indexed: 06/10/2023]
Abstract
Blast-induced traumatic brain injury (TBI) has been affecting combatants and civilians. The blast pressure wave is thought to have a significant contribution to blast-related TBI. Due to the limitations and difficulties of conducting blast tests on surrogates, computational modelling has been used as a key method for exploring this field. However, the blast wave modelling methods reported in current literature have drawbacks. They either cannot generate the desirable blast pressure wave history or they are unable to accurately simulate the blast wave/structure interaction. In addition, boundary conditions, which can have significant effects on model predictions, have not been described adequately. Here, we critically assess the commonly used methods for simulating blast wave propagation in air (open-field blast) and its interaction with the human body. We investigate the predicted blast wave time history, blast wave transmission, and the effects of various boundary conditions in three-dimensional (3D) models of blast prediction. We propose a suitable meshing topology, which enables accurate prediction of blast wave propagation and interaction with the human head and significantly decreases the computational cost in 3D simulations. Finally, we predict strain and strain rate in the human brain during blast wave exposure and show the influence of the blast wave modelling methods on the brain response. The findings presented here can serve as guidelines for accurately modelling blast wave generation and interaction with the human body for injury biomechanics studies and design of prevention systems.
Collapse
Affiliation(s)
- Xiancheng Yu
- Dyson School of Design Engineering, Imperial College London, South Kensington Campus, London, UK
- Centre for Blast Injury Studies, Imperial College London, South Kensington Campus, London, UK
| | - Mazdak Ghajari
- Dyson School of Design Engineering, Imperial College London, South Kensington Campus, London, UK
- Centre for Blast Injury Studies, Imperial College London, South Kensington Campus, London, UK
| |
Collapse
|
25
|
Sutar S, Ganpule S. Investigation of wave propagation through head layers with focus on understanding blast wave transmission. Biomech Model Mechanobiol 2019; 19:875-892. [PMID: 31745681 DOI: 10.1007/s10237-019-01256-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 11/06/2019] [Indexed: 11/25/2022]
Abstract
Blast-induced traumatic brain injury (bTBI) is a critical health concern. This issue is being addressed in terms of identifying a cause-effect relationship between the mechanical insult in the form of a blast and resulting injury to the brain. Understanding wave propagation through the head is an important aspect in this regard. The objective of this work was to study the blast wave propagation through the layered architecture of the head with an emphasis on understanding the wave transmission mechanism. Toward this end, one-dimensional (1D) finite element head model is built for a simplified surrogate, human, and rat. Motivated from experimental investigations, four different head layer configurations have been considered. These configurations are: (A) Skull-Brain, (B) Skin-Skull-Brain, (C) Skin-Skull-Dura-Arachnoid-CSF-Pia-Brain, (D) Skin-Skull-Dura-Arachnoid-AT-Pia-Brain. The validated head model is subjected to flattop and Friedlander loading implied in the blast, and the resulting response is evaluated in terms of brain pressures. Our results suggest that wave propagation through head parenchyma plays an important role in blast wave transmission. The thickness, material properties of head layers, and rise time of an input pulse govern the temporal evolution of pressure in the brain. The key findings of this work are: (a) Skin and meninges amplify the applied input pressure, whereas air sinus has an attenuation effect. (b) Model is able to describe experimentally recorded peak pressures and rise times in the brain, including variations within the aforementioned experimental head models of TBI. This reinforces that the wave transmission is an important loading pathway to the brain. (c) Equivalent layer theory for modeling meningeal layers as a single layer has been proposed, and it gives reasonable agreement with each meningeal layer modeled explicitly. This modeling approach has a great utility in 3D head models. The potential applications of 1D head model in evaluation of new helmet materials, brain sensor calibration, and brain pressure estimation for a given explosive strength have also been demonstrated. Overall, these results provide important insights into the understanding of mechanics of blast wave transmission in the head.
Collapse
Affiliation(s)
- Sunil Sutar
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - S Ganpule
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee, 247667, India.
| |
Collapse
|
26
|
Kubli LR, Pinto RL, Burrows HL, Littlefield PD, Brungart DS. The effects of repeated low-level blast exposure on hearing in marines. Noise Health 2019; 19:227-238. [PMID: 28937017 PMCID: PMC5644382 DOI: 10.4103/nah.nah_58_16] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND The study evaluates a group of Military Service Members specialized in blast explosive training called "Breachers" who are routinely exposed to multiple low-level blasts while teaching breaching at the U.S. Marine Corps in Quantico Virginia. The objective of this study was to determine if there are any acute or long-term auditory changes due to repeated low-level blast exposures used in training. The performance of the instructor group "Breachers" was compared to a control group, "Engineers". METHODS A total of 11 Breachers and four engineers were evaluated in the study. The participants received comprehensive auditory tests, including pure-tone testing, speech-in-noise (SIN) measures, and central auditory behavioral and objective tests using early and late (P300) auditory evoked potentials over a period of 17 months. They also received shorter assessments immediately following the blast-exposure onsite at Quantico. RESULTS No acute or longitudinal effects were identified. However, there were some interesting baseline effects found in both groups. Contrary to the expected, the onsite hearing thresholds and distortion product otoacoustic emissions were slightly better at a few frequencies immediately after blast-exposure than measurements obtained with the same equipment weeks to months after each blast-exposure. CONCLUSIONS To date, the current study is the most comprehensive study that evaluates the long-term effects of blast-exposure on hearing. Despite extensive testing to assess changes, the findings of this study suggest that the levels of current exposures used in this military training environment do not seem to have an obvious deleterious effect on hearing.
Collapse
Affiliation(s)
- Lina R Kubli
- US Army Public Health Center (Provisional), Aberdeen Proving Grounds, Edgewood, Maryland; Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | - Robin L Pinto
- Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | - Holly L Burrows
- Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | - Philip D Littlefield
- Department of Otolaryngology, Walter Reed National Military Medical Center, Bethesda, Maryland; Department of Otolaryngology, Tripler Army Medical Center, Honolulu, Hawaii, USA
| | - Douglas S Brungart
- Audiology and Speech Pathology Center, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| |
Collapse
|
27
|
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.
Collapse
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.
| |
Collapse
|
28
|
Multi-Scale Modeling of Head Kinematics and Brain Tissue Response to Blast Exposure. Ann Biomed Eng 2019; 47:1993-2004. [PMID: 30671753 DOI: 10.1007/s10439-018-02193-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/19/2018] [Indexed: 12/22/2022]
Abstract
Injuries resulting from blast exposure have been increasingly prevalent in recent conflicts, with a particular focus on the risk of head injury. In the current study, a multibody model (GEBOD) was used to investigate the gross kinematics resulting from blast exposure, including longer duration events such as the fall and ground impact. Additionally, detailed planar head models, in the sagittal and transverse planes, were used to model the primary blast wave interaction with the head, and resulting tissue response. For severe blast load cases (scaled distance less than 2), the translational head accelerations during primary blast were found to increase as the height-of-burst (HOB) was lowered, while the HOB was found to have no effect for cases with scaled distance greater than 2. The HOB was found to affect both the magnitude and direction of rotational accelerations, with increasing magnitudes as the HOB deviated from the height of the head. The choice of ground contact stiffness was found to greatly affect the predicted head accelerations during ground impact. For a medium soil ground material, the kinematics during ground impact were greater for scaled distances exceeding 1.5, below which the primary blast produced greater kinematic head response.
Collapse
|
29
|
Townsend MT, Alay E, Skotak M, Chandra N. Effect of Tissue Material Properties in Blast Loading: Coupled Experimentation and Finite Element Simulation. Ann Biomed Eng 2018; 47:2019-2032. [PMID: 30523466 DOI: 10.1007/s10439-018-02178-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 11/28/2018] [Indexed: 01/26/2023]
Abstract
Computational models of blast-induced traumatic brain injury (bTBI) require a robust definition of the material models of the brain. The mechanical constitutive models of these tissues are difficult to characterize, leading to a wide range of values reported in literature. Therefore, the sensitivity of the intracranial pressure (ICP) and maximum principal strain to variations in the material model of the brain was investigated through a combined computational and experimental approach. A finite element model of a rat was created to simulate a shock wave exposure, guided by the experimental measurements of rats subjected to shock loading conditions corresponding to that of mild traumatic brain injury in a field-validated shock tube. In the numerical model, the properties of the brain were parametrically varied. A comparison of the ICP measured at two locations revealed that experimental and simulated ICP were higher in the cerebellum (p < 0.0001), highlighting the significance of pressure sensor locations within the cranium. The ICP and strain were correlated with the long-term bulk (p < 0.0001) and shear moduli (p < 0.0001), with an 80 MPa effective bulk modulus value matching best with experimental measurements. In bTBI, the solution is sensitive to the brain material model, necessitating robust validation methods.
Collapse
Affiliation(s)
- Molly T Townsend
- Biomedical Engineering Department, New Jersey Institute of Technology, Newark, NJ, USA
| | - Eren Alay
- Biomedical Engineering Department, New Jersey Institute of Technology, Newark, NJ, USA
| | - Maciej Skotak
- Biomedical Engineering Department, New Jersey Institute of Technology, Newark, NJ, USA
| | - Namas Chandra
- Biomedical Engineering Department, New Jersey Institute of Technology, Newark, NJ, USA.
| |
Collapse
|
30
|
Studlack PE, Keledjian K, Farooq T, Akintola T, Gerzanich V, Simard JM, Keller A. Blast-induced brain injury in rats leads to transient vestibulomotor deficits and persistent orofacial pain. Brain Inj 2018; 32:1866-1878. [PMID: 30346868 PMCID: PMC6381394 DOI: 10.1080/02699052.2018.1536282] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 09/18/2018] [Accepted: 10/03/2018] [Indexed: 12/12/2022]
Abstract
Blast-induced traumatic brain injury (blast-TBI) is associated with vestibulomotor dysfunction, persistent post-traumatic headaches and post-traumatic stress disorder, requiring extensive treatments and reducing quality-of-life. Treatment and prevention of these devastating outcomes require an understanding of their underlying pathophysiology through studies that take advantage of animal models. Here, we report that cranium-directed blast-TBI in rats results in signs of pain that last at least 8 weeks after injury. These occur without significantly elevated behavioural markers of anxiety-like conditions and are not associated with glial up-regulation in sensory thalamic nuclei. These injuries also produce transient vestibulomotor abnormalities that resolve within 3 weeks of injury. Thus, blast-TBI in rats recapitulates aspects of the human condition.
Collapse
Affiliation(s)
- Paige E. Studlack
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St., HSFII S251, Baltimore, MD 21201, USA
| | - Kaspar Keledjian
- Department of Neurosurgery, University of Maryland School of Medicine, 10 S. Pine St., MSTF 634B, Baltimore, MD 21201, USA
| | - Tayyiaba Farooq
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St., HSFII S251, Baltimore, MD 21201, USA
| | - Titilola Akintola
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St., HSFII S251, Baltimore, MD 21201, USA
| | - Volodymyr Gerzanich
- Department of Neurosurgery, University of Maryland School of Medicine, 10 S. Pine St., MSTF 634B, Baltimore, MD 21201, USA
| | - J. Marc Simard
- Department of Neurosurgery, University of Maryland School of Medicine, 10 S. Pine St., MSTF 634B, Baltimore, MD 21201, USA
| | - Asaf Keller
- Program in Neuroscience and Department of Anatomy and Neurobiology, University of Maryland School of Medicine, 20 Penn St., HSFII S251, Baltimore, MD 21201, USA
| |
Collapse
|
31
|
Teferra K, Tan XG, Iliopoulos A, Michopoulos J, Qidwai S. Effect of human head morphological variability on the mechanical response of blast overpressure loading. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3109. [PMID: 29804323 DOI: 10.1002/cnm.3109] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Accepted: 05/20/2018] [Indexed: 06/08/2023]
Abstract
A methodology is introduced to investigate the effect of intersubject head morphological variability on the mechanical response of the brain when subjected to blast overpressure loading. Nonrigid image registration techniques are leveraged to warp a manually segmented template model to an arbitrary number of subjects following a procedure to coarsely segment the subjects in batch. Finite element meshes are autogenerated, and blast analysis is conducted. The template model is initially constructed to enable the full automated implementation and application of the proposed methodology. The application of the proposed approach for an anterior-oriented blast has been demonstrated, and the results reveal that the pressure response in the brain does exhibit some dependence on head morphological variability. While the magnitude of the peak pressure response can vary by more than 30%, its location within the brain is unaffected by head morphological variability. A linear least squares analysis was conducted to demonstrate that the peak magnitude of pressure is uncorrelated with head volume while it is correlated with aspect ratio relating to the amount of exposed surface area to the blast. These features of the pressure response are likely due to the peak pressure occurring during the early stages of stress wave transmission and reflection. As a result, the pressure response due to blast overpressure loading is predominantly loading dependent while morphological variability has a secondary effect.
Collapse
Affiliation(s)
| | - X Gary Tan
- US Naval Research Laboratory, Washington, DC, USA
| | | | | | - Siddiq Qidwai
- Division of Civil, Mechanical and Manufacturing Innovation, NSF, Alexandria, VA, USA
| |
Collapse
|
32
|
BERTUCCI ROBBIN, PRABHU RAJ, HORSTEMEYER MF, MAO YUXIONG, GILBRECH RYAN, SHENG JAMES, WILLIAMS LAKIESHAN, LIAO JUN. AN ANATOMICALLY-RELEVANT COMPUTATIONAL MODEL FOR PRIMARY BLAST EFFECTS ON THE HUMAN LOWER EXTREMITY. J MECH MED BIOL 2018. [DOI: 10.1142/s0219519418500574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Explosions pose serious threats to US soldiers and civilians, often resulting in disability and death. Due to its direct contact with the ground, the lower extremity is commonly injured, and the blast loading often results in traumatic amputations and soft tissue rupture. The exact overpressure signatures that induce these primary blast injuries are still unknown. A high fidelity FE model of the lower extremity blast condition is thus essential to reveal the underlying injury mechanism. In this study, we created an anatomically-relevant lower extremity model and analyzed several different blast cases using Abaqus/Explicit. Pressures, impulses, stresses, and maximum principal strains were evaluated and compared to previous results in the literature. Our FE model and simulation were able to capture the detailed structural responses to a blast wave in the lower extremity; moreover, we showed that the injury patterns could be correlated to biomechanical metrics that may have incited pathologies such as amputations and compartment syndrome. The lower extremity FE model developed in this project allows for a cost-effective and reproducible analysis of blast events and has the potential to improve injury metrics and personal protective equipment design by accurately evaluating the damage imposed on the lower extremity.
Collapse
Affiliation(s)
- ROBBIN BERTUCCI
- Department of Biological Engineering, Mississippi State University, Mississippi State, MS 39762, USA
| | - RAJ PRABHU
- Department of Biological Engineering, Mississippi State University, Mississippi State, MS 39762, USA
| | - M. F. HORSTEMEYER
- Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - YUXIONG MAO
- Center for Advanced Vehicular Systems, Mississippi State University, Mississippi State, MS 39762, USA
| | - RYAN GILBRECH
- Department of Biological Engineering, Mississippi State University, Mississippi State, MS 39762, USA
| | - JAMES SHENG
- U. S. Army Tank Automotive Research, Development and Engineering Center (TARDEC), USA
| | - LAKIESHA N. WILLIAMS
- Department of Biological Engineering, Mississippi State University, Mississippi State, MS 39762, USA
| | - JUN LIAO
- Department of Biological Engineering, Mississippi State University, Mississippi State, MS 39762, USA
- Department of Bioengineering, University of Texas, Arlington, TX 79010, USA
| |
Collapse
|
33
|
Abstract
PURPOSE OF REVIEW This review investigates the relationship between sensory sensitivity and traumatic brain injury (TBI), and the role sensory sensitivity plays in chronic disability. RECENT FINDINGS TBI is a significant cause of disability with a range of physical, cognitive, and mental health consequences. Sensory sensitivities (e.g., noise and light) are among the most frequently reported, yet least outwardly recognizable symptoms following TBI. Clinicians and scientists alike have yet to identify consistent nomenclature for defining noise and light sensitivity, making it difficult to accurately and reliably assess their influence. Noise and light sensitivity can profoundly affect critical aspects of independent function including communication, productivity, socialization, cognition, sleep, and mental health. Research examining the prevalence of sensory sensitivity and evidence for the association of sensory sensitivity with TBI is inconclusive. Evidence-based interventions for sensory sensitivity, particularly following TBI, are lacking.
Collapse
|
34
|
|
35
|
Esenaliev RO, Petrov IY, Petrov Y, Guptarak J, Boone DR, Mocciaro E, Weisz H, Parsley MA, Sell SL, Hellmich H, Ford JM, Pogue C, DeWitt D, Prough DS, Micci MA. Nano-Pulsed Laser Therapy Is Neuroprotective in a Rat Model of Blast-Induced Neurotrauma. J Neurotrauma 2018; 35:1510-1522. [PMID: 29562823 PMCID: PMC5998828 DOI: 10.1089/neu.2017.5249] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We have developed a novel, non-invasive nano-pulsed laser therapy (NPLT) system that combines the benefits of near-infrared laser light (808 nm) and ultrasound (optoacoustic) waves, which are generated with each short laser pulse within the tissue. We tested NPLT in a rat model of blast-induced neurotrauma (BINT) to determine whether transcranial application of NPLT provides neuroprotective effects. The laser pulses were applied on the intact rat head 1 h after injury using a specially developed fiber-optic system. Vestibulomotor function was assessed on post-injury days (PIDs) 1–3 on the beam balance and beam walking tasks. Cognitive function was assessed on PIDs 6–10 using a working memory Morris water maze (MWM) test. BDNF and caspase-3 messenger RNA (mRNA) expression was measured by quantitative real-time PCR (qRT-PCR) in laser-captured cortical neurons. Microglia activation and neuronal injury were assessed in brain sections by immunofluorescence using specific antibodies against CD68 and active caspase-3, respectively. In the vestibulomotor and cognitive (MWM) tests, NPLT-treated animals performed significantly better than the untreated blast group and similarly to sham animals. NPLT upregulated mRNA encoding BDNF and downregulated the pro-apoptotic protein caspase-3 in cortical neurons. Immunofluorescence demonstrated that NPLT inhibited microglia activation and reduced the number of cortical neurons expressing activated caspase-3. NPLT also increased expression of BDNF in the hippocampus and the number of proliferating progenitor cells in the dentate gyrus. Our data demonstrate a neuroprotective effect of NPLT and prompt further studies aimed to develop NPLT as a therapeutic intervention after traumatic brain injury (TBI).
Collapse
Affiliation(s)
- Rinat O Esenaliev
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas.,2 Department of Neuroscience and Cell Biology, University of Texas Medical Branch , Galveston, Texas.,3 Center for Biomedical Engineering, University of Texas Medical Branch , Galveston, Texas
| | - Irene Y Petrov
- 3 Center for Biomedical Engineering, University of Texas Medical Branch , Galveston, Texas
| | - Yuriy Petrov
- 3 Center for Biomedical Engineering, University of Texas Medical Branch , Galveston, Texas
| | - Jutatip Guptarak
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Debbie R Boone
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Emanuele Mocciaro
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Harris Weisz
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Margaret A Parsley
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Stacy L Sell
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Helen Hellmich
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Jonathan M Ford
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Connor Pogue
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Douglas DeWitt
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Donald S Prough
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| | - Maria-Adelaide Micci
- 1 Department of Anesthesiology, University of Texas Medical Branch , Galveston, Texas
| |
Collapse
|
36
|
Do blast induced skull flexures result in axonal deformation? PLoS One 2018; 13:e0190881. [PMID: 29547663 PMCID: PMC5856259 DOI: 10.1371/journal.pone.0190881] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 12/21/2017] [Indexed: 12/28/2022] Open
Abstract
Subject-specific computer models (male and female) of the human head were used to investigate the possible axonal deformation resulting from the primary phase blast-induced skull flexures. The corresponding axonal tractography was explicitly incorporated into these finite element models using a recently developed technique based on the embedded finite element method. These models were subjected to extensive verification against experimental studies which examined their pressure and displacement response under a wide range of loading conditions. Once verified, a parametric study was developed to investigate the axonal deformation for a wide range of loading overpressures and directions as well as varying cerebrospinal fluid (CSF) material models. This study focuses on early times during a blast event, just as the shock transverses the skull (< 5 milliseconds). Corresponding boundary conditions were applied to eliminate the rotation effects and the resulting axonal deformation. A total of 138 simulations were developed– 128 simulations for studying the different loading scenarios and 10 simulations for studying the effects of CSF material model variance–leading to a total of 10,702 simulation core hours. Extreme strains and strain rates along each of the fiber tracts in each of these scenarios were documented and presented here. The results suggest that the blast-induced skull flexures result in strain rates as high as 150–378 s-1. These high-strain rates of the axonal fiber tracts, caused by flexural displacement of the skull, could lead to a rate dependent micro-structural axonal damage, as pointed by other researchers.
Collapse
|
37
|
Song H, Cui J, Simonyi A, Johnson CE, Hubler GK, DePalma RG, Gu Z. Linking blast physics to biological outcomes in mild traumatic brain injury: Narrative review and preliminary report of an open-field blast model. Behav Brain Res 2018; 340:147-158. [DOI: 10.1016/j.bbr.2016.08.037] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 08/13/2016] [Accepted: 08/19/2016] [Indexed: 12/14/2022]
|
38
|
Rodriguez UA, Zeng Y, Deyo D, Parsley MA, Hawkins BE, Prough DS, DeWitt DS. Effects of Mild Blast Traumatic Brain Injury on Cerebral Vascular, Histopathological, and Behavioral Outcomes in Rats. J Neurotrauma 2018; 35:375-392. [PMID: 29160141 PMCID: PMC5784797 DOI: 10.1089/neu.2017.5256] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
To determine the effects of mild blast-induced traumatic brain injury (bTBI), several groups of rats were subjected to blast injury or sham injury in a compressed air-driven shock tube. The effects of bTBI on relative cerebral perfusion (laser Doppler flowmetry [LDF]), and mean arterial blood pressure (MAP) cerebral vascular resistance were measured for 2 h post-bTBI. Dilator responses to reduced intravascular pressure were measured in isolated middle cerebral arterial (MCA) segments, ex vivo, 30 and 60 min post-bTBI. Neuronal injury was assessed (Fluoro-Jade C [FJC]) 24 and 48 h post-bTBI. Neurological outcomes (beam balance and walking tests) and working memory (Morris water maze [MWM]) were assessed 2 weeks post-bTBI. Because impact TBI (i.e., non-blast TBI) is often associated with reduced cerebral perfusion and impaired cerebrovascular function in part because of the generation of reactive oxygen and nitrogen species such as peroxynitrite (ONOO-), the effects of the administration of the ONOO- scavenger, penicillamine methyl ester (PenME), on cerebral perfusion and cerebral vascular resistance were measured for 2 h post-bTBI. Mild bTBI resulted in reduced relative cerebral perfusion and MCA dilator responses to reduced intravascular pressure, increases in cerebral vascular resistance and in the numbers of FJC-positive cells in the brain, and significantly impaired working memory. PenME administration resulted in significant reductions in cerebral vascular resistance and a trend toward increased cerebral perfusion, suggesting that ONOO- may contribute to blast-induced cerebral vascular dysfunction.
Collapse
Affiliation(s)
- Uylissa A. Rodriguez
- Cell Biology Graduate Program, Department of Neuroscience and Cell Biology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Yaping Zeng
- The Moody Project for Translational Traumatic Brain Injury Research, Charles R. Allen Research Laboratories, Department of Anesthesiology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Donald Deyo
- The Moody Project for Translational Traumatic Brain Injury Research, Charles R. Allen Research Laboratories, Department of Anesthesiology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Margaret A. Parsley
- The Moody Project for Translational Traumatic Brain Injury Research, Charles R. Allen Research Laboratories, Department of Anesthesiology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Bridget E. Hawkins
- Cell Biology Graduate Program, Department of Neuroscience and Cell Biology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Donald S. Prough
- The Moody Project for Translational Traumatic Brain Injury Research, Charles R. Allen Research Laboratories, Department of Anesthesiology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| | - Douglas S. DeWitt
- Cell Biology Graduate Program, Department of Neuroscience and Cell Biology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
- The Moody Project for Translational Traumatic Brain Injury Research, Charles R. Allen Research Laboratories, Department of Anesthesiology, Department of Anesthesiology, University of Texas Medical Branch, Galveston, Texas
| |
Collapse
|
39
|
Tan LB, Tse KM, Tan YH, Sapingi MAB, Tan VBC, Lee HP. Face shield design against blast-induced head injuries. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33. [PMID: 28329435 DOI: 10.1002/cnm.2884] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 01/07/2017] [Accepted: 03/19/2017] [Indexed: 06/06/2023]
Abstract
Blast-induced traumatic brain injury has been on the rise in recent years because of the increasing use of improvised explosive devices in conflict zones. Our study investigates the response of a helmeted human head subjected to a blast of 1 atm peak overpressure, for cases with and without a standard polycarbonate (PC) face shield and for face shields comprising of composite PC and aerogel materials and with lateral edge extension. The novel introduction of aerogel into the laminate face shield is explored and its wave-structure interaction mechanics and performance in blast mitigation is analysed. Our numerical results show that the face shield prevented direct exposure of the blast wave to the face and help delays the transmission of the blast to reduce the intracranial pressures (ICPs) at the parietal lobe. However, the blast wave can diffract and enter the midface region at the bottom and side edges of the face shield, resulting in traumatic brain injury. This suggests that the bottom and sides of the face shield are important regions to focus on to reduce wave ingress. The laminated PC/aerogel/PC face shield yielded higher peak positive and negative ICPs at the frontal lobe, than the original PC one. For the occipital and temporal brain regions, the laminated face shield performed better than the original. The composite face shield with extended edges reduced ICP at the temporal lobe but increases ICP significantly at the parietal lobe, which suggests that a greater coverage may not lead to better mitigating effects.
Collapse
Affiliation(s)
- Long Bin Tan
- Department of Mechanical Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore
| | - Kwong Ming Tse
- Department of Mechanical Engineering, University of Melbourne, Parkville, VIC, 3010, Australia
| | - Yuan Hong Tan
- Department of Mechanical Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore
| | - Mohamad Ali Bin Sapingi
- Department of Mechanical Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore
| | - Vincent Beng Chye Tan
- Department of Mechanical Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore
| | - Heow Pueh Lee
- Department of Mechanical Engineering, National University of Singapore, 21 Lower Kent Ridge Rd, 119077, Singapore
| |
Collapse
|
40
|
Hua Y, Tong J, Ghate D, Kedar S, Gu L. Intracranial Pressure Influences the Behavior of the Optic Nerve Head. J Biomech Eng 2017; 139:2593203. [PMID: 27935009 DOI: 10.1115/1.4035406] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2016] [Indexed: 11/08/2022]
Abstract
In this work, the biomechanical responses of the optic nerve head (ONH) to acute elevations in intracranial pressure (ICP) were systematically investigated through numerical modeling. An orthogonal experimental design was developed to quantify the influence of ten input factors that govern the anatomy and material properties of the ONH on the peak maximum principal strain (MPS) in the lamina cribrosa (LC) and postlaminar neural tissue (PLNT). Results showed that the sensitivity of ONH responses to various input factors was region-specific. In the LC, the peak MPS was most strongly dependent on the sclera thickness, LC modulus, and scleral canal size, whereas in the PLNT, the peak MPS was more sensitive to the scleral canal size, neural tissue modulus, and pia mater modulus. The enforcement of clinically relevant ICP in the retro-orbital subarachnoid space influenced the sensitivity analysis. It also induced much larger strains in the PLNT than in the LC. Moreover, acute elevation of ICP leads to dramatic strain distribution changes in the PLNT, but had minimal impact on the LC. This work could help to better understand patient-specific responses, to provide guidance on biomechanical factors resulting in optic nerve diseases, such as glaucoma, papilledema, and ischemic optic neuropathy, and to illuminate the possibilities for exploiting their potential to treat and prevent ONH diseases.
Collapse
Affiliation(s)
- Yi Hua
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656
| | - Junfei Tong
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656
| | - Deepta Ghate
- Stanley Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE 68105-1119;Center for Advanced Surgical Technology, University of Nebraska Medical Center, Omaha, NE 68198-6245
| | - Sachin Kedar
- Stanley Truhlsen Eye Institute, University of Nebraska Medical Center, Omaha, NE 68105-1119;Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE 68198-8440
| | - Linxia Gu
- Department of Mechanical and Materials Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588-0656;Center for Advanced Surgical Technology, University of Nebraska Medical Center, Omaha, NE 68198-6245;Nebraska Center for Materials and Nanoscience, Lincoln, NE 68588-0656 e-mail:
| |
Collapse
|
41
|
Garcia-Gonzalez D, Jayamohan J, Sotiropoulos S, Yoon SH, Cook J, Siviour C, Arias A, Jérusalem A. On the mechanical behaviour of PEEK and HA cranial implants under impact loading. J Mech Behav Biomed Mater 2017; 69:342-354. [DOI: 10.1016/j.jmbbm.2017.01.012] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Revised: 01/03/2017] [Accepted: 01/08/2017] [Indexed: 10/20/2022]
|
42
|
Simulated blast overpressure induces specific astrocyte injury in an ex vivo brain slice model. PLoS One 2017; 12:e0175396. [PMID: 28403239 PMCID: PMC5389806 DOI: 10.1371/journal.pone.0175396] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 03/25/2017] [Indexed: 12/14/2022] Open
Abstract
Exposure to explosive blasts can produce functional debilitation in the absence of brain pathology detectable at the scale of current diagnostic imaging. Transient (ms) overpressure components of the primary blast wave are considered to be potentially damaging to the brain. Astrocytes participate in neuronal metabolic maintenance, blood–brain barrier, regulation of homeostatic environment, and tissue remodeling. Damage to astrocytes via direct physical forces has the potential to disrupt local and global functioning of neuronal tissue. Using an ex vivo brain slice model, we tested the hypothesis that viable astrocytes within the slice could be injured simply by transit of a single blast wave consisting of overpressure alone. A polymer split Hopkinson pressure bar (PSHPB) system was adapted to impart a single positive pressure transient with a comparable magnitude to those that might be present inside the head. A custom built test chamber housing the brain tissue slice incorporated revised design elements to reduce fluid space and promote transit of a uniform planar waveform. Confocal microscopy, stereology, and morphometry of glial fibrillary acidic protein (GFAP) immunoreactivity revealed that two distinct astrocyte injury profiles were identified across a 4 hr post-test survival interval: (a) presumed conventional astrogliosis characterized by enhanced GFAP immunofluorescence intensity without significant change in tissue area fraction and (b) a process comparable to clasmatodendrosis, an autophagic degradation of distal processes that has not been previously associated with blast induced neurotrauma. Analysis of astrocyte branching revealed early, sustained, and progressive differences distinct from the effects of slice incubation absent overpressure testing. Astrocyte vulnerability to overpressure transients indicates a potential for significant involvement in brain blast pathology and emergent dysfunction. The testing platform can isolate overpressure injury phenomena to provide novel insight on physical and biological mechanisms.
Collapse
|
43
|
Sarvghad-Moghaddam H, Rezaei A, Ziejewski M, Karami G. Evaluation of brain tissue responses because of the underwash overpressure of helmet and faceshield under blast loading. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33. [PMID: 26968860 DOI: 10.1002/cnm.2782] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 01/06/2016] [Accepted: 03/06/2016] [Indexed: 05/16/2023]
Abstract
Head protective tools such as helmets and faceshields can induce a localized high pressure region on the skull because of the underwash of the blast waves. Whether this underwash overpressure can affect the brain tissue response is still unknown. Accordingly, a computational approach was taken to confirm the incidence of underwash with regards to blast direction, as well as examine the influence of this effect on the mechanical responses of the brain. The variation of intracranial pressure (ICP) as one of the major injury predictors, as well as the maximum shear stress were mainly addressed in this study. Using a nonlinear finite element (FE) approach, generation and interaction of blast waves with the unprotected, helmeted, and fully protected (helmet and faceshield protected) FE head models were modeled using a multi-material arbitrary Lagrangian-Eulerian (ALE) method and a fluid-structure interaction (FSI) coupling algorithm. The underwash incidence overpressure was found to greatly change with the blast direction. Moreover, while underwash induced ICP (U-ICP) did not exceed the peak ICP of the unprotected head, it was comparable and even more than the peak ICP imposed on the protected heads by the primary shockwaves (Coup-ICP). It was concluded that while both helmet and faceshield protected the head against blast waves, the underwash overpressure affected the brain tissue response and altered the dynamic load experienced by the brain as it led to increased ICP levels at the countercoup site, imparted elevated skull flexure, and induced high negative pressure regions. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.
Collapse
Affiliation(s)
- Hesam Sarvghad-Moghaddam
- Department of Mechanical Engineering, North Dakota State University Fargo, ND, 58108-6050, U.S.A
| | - Asghar Rezaei
- Department of Mechanical Engineering, North Dakota State University Fargo, ND, 58108-6050, U.S.A
| | - Mariusz Ziejewski
- Department of Mechanical Engineering, North Dakota State University Fargo, ND, 58108-6050, U.S.A
| | - Ghodrat Karami
- Department of Mechanical Engineering, North Dakota State University Fargo, ND, 58108-6050, U.S.A
| |
Collapse
|
44
|
Comparative analysis of bleeding risk by the location and shape of arachnoid cysts: a finite element model analysis. Childs Nerv Syst 2017; 33:125-134. [PMID: 27718069 DOI: 10.1007/s00381-016-3252-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 02/08/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Although arachnoid cysts (ACs) are observed in various locations, only sylvian ACs are mainly regarded to be associated with bleeding. The reason for this selective association of sylvian ACs with bleeding is not understood well. This study is to investigate the effect of the location and shape of ACs on the risk of bleeding. METHODS A developed finite element model of the head/brain was modified for models of sylvian, suprasellar, and posterior fossa ACs. A spherical AC was placed at each location to compare the effect of AC location. Bowl-shaped and oval-shaped AC models were developed to compare the effect by shape. The shear force on the spot-weld elements (SFSW) was measured between the dura and the outer wall of the ACs or the comparable arachnoid membrane in the normal model. RESULTS All AC models revealed higher SFSW than comparable normal models. By location, sylvian AC displayed the highest SFSW for frontal and lateral impacts. By shape, small outer wall AC models showed higher SFSW than large wall models in sylvian area and lower SFSW than large ones in posterior fossa. In regression analysis, the presence of AC was the only independent risk of bleeding. CONCLUSION The bleeding mechanism of ACs is very complex, and the risk quantification failed to show a significant role of location and shape of ACs. The presence of AC increases shear force on impact condition and may be a risk factor of bleeding, and sylvian location of AC may not have additive risks of AC bleeding.
Collapse
|
45
|
Yeh P, Guan Koay C, Wang B, Morissette J, Sham E, Senseney J, Joy D, Kubli A, Yeh C, Eskay V, Liu W, French LM, Oakes TR, Riedy G, Ollinger J. Compromised Neurocircuitry in Chronic Blast-Related Mild Traumatic Brain Injury. Hum Brain Mapp 2017; 38:352-369. [PMID: 27629984 PMCID: PMC6867097 DOI: 10.1002/hbm.23365] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 08/16/2016] [Accepted: 08/23/2016] [Indexed: 12/20/2022] Open
Abstract
The aim of this study was to apply recently developed automated fiber segmentation and quantification methods using diffusion tensor imaging (DTI) and DTI-based deterministic and probabilistic tractography to access local and global diffusion changes in blast-induced mild traumatic brain injury (bmTBI). Two hundred and two (202) male active US service members who reported persistent post-concussion symptoms for more than 6 months after injury were recruited. An additional forty (40) male military controls were included for comparison. DTI results were examined in relation to post-concussion and post-traumatic stress disorder (PTSD) symptoms. No significant group difference in DTI metrics was found using voxel-wise analysis. However, group comparison using tract profile analysis and tract specific analysis, as well as single subject analysis using tract profile analysis revealed the most prominent white matter microstructural injury in chronic bmTBI patients over the frontal fiber tracts, that is, the front-limbic projection fibers (cingulum bundle, uncinate fasciculus), the fronto-parieto-temporal association fibers (superior longitudinal fasciculus), and the fronto-striatal pathways (anterior thalamic radiation). Effects were noted to be sensitive to the number of previous blast exposures, with a negative association between fractional anisotropy (FA) and time since most severe blast exposure in a subset of the multiple blast-exposed group. However, these patterns were not observed in the subgroups classified using macrostructural changes (T2 white matter hyperintensities). Moreover, post-concussion symptoms and PTSD symptoms, as well as neuropsychological function were associated with low FA in the major nodes of compromised neurocircuitry. Hum Brain Mapp 38:352-369, 2017. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Ping‐Hong Yeh
- Henry Jackson Foundation for the Advancement of Military MedicineRockledgeMaryland
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Cheng Guan Koay
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Binquan Wang
- Henry Jackson Foundation for the Advancement of Military MedicineRockledgeMaryland
| | - John Morissette
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Elyssa Sham
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Justin Senseney
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - David Joy
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Alex Kubli
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Chen‐Haur Yeh
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Victora Eskay
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Wei Liu
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Louis M. French
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
- Center for Neuroscience and Regenerative Medicine (CNRM)Uniformed Services University of the Health Sciences (USUHS)BethesdaMaryland
| | - Terrence R. Oakes
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| | - Gerard Riedy
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
- Center for Neuroscience and Regenerative Medicine (CNRM)Uniformed Services University of the Health Sciences (USUHS)BethesdaMaryland
| | - John Ollinger
- National Intrepid Center of Excellence (NICoE)Walter Reed National Military Medical CenterBethesdaMaryland
| |
Collapse
|
46
|
Feng K, Zhang L, Jin X, Chen C, Kallakuri S, Saif T, Cavanaugh J, King A. Biomechanical Responses of the Brain in Swine Subject to Free-Field Blasts. Front Neurol 2016; 7:179. [PMID: 27822197 PMCID: PMC5075707 DOI: 10.3389/fneur.2016.00179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/04/2016] [Indexed: 01/05/2023] Open
Abstract
Blast-induced traumatic brain injury (bTBI) is a signature wound of modern warfare. The current incomplete understanding of its injury mechanism impedes the development of strategies for effective protection of bTBI. Despite a considerable amount of experimental animal studies focused on the evaluation of brain neurotrauma caused by blast exposure, there is very limited knowledge on the biomechanical responses of the gyrenecephalic brain subjected to primary free-field blast waves imposed in vivo. This study aims to evaluate the external and internal mechanical responses of the brain against different levels of blast loading with Yucatan swine in free field. The incident overpressure (IOP) was generated using 3.6 kg of C4 charge placed at three standoff distances from the swine. Five swine were exposed to a total of 19 blasts. The three average peak IOP pressure levels in this study were 148.8, 278.9, and 409.2 kPa as measured by a pencil probe. The duration of the first positive wave was in the range of 2.1–3 ms. Pressure changes in the brain and head kinematics were recorded with intracranial pressure (ICP) sensors, linear accelerometers, and angular rate sensors. The corresponding average peak ICPs were in the range of 79–143, 210–281, and 311–414 kPa designated as low, medium, and high blast level, respectively. Peak head linear accelerations were in the range of 120–412 g. A positive correlation between IOP and its corresponding biomechanical responses of the brain was also observed. These experimental data can be used to validate computer models of bTBI.
Collapse
Affiliation(s)
- Ke Feng
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| | - Liying Zhang
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| | - Xin Jin
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| | - Chaoyang Chen
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| | - Srinivasu Kallakuri
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| | - Tal Saif
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| | - John Cavanaugh
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| | - Albert King
- Department of Biomedical Engineering, Wayne State University , Detroit, MI , USA
| |
Collapse
|
47
|
Affiliation(s)
- Graham Martin
- Accident Compensation Corporation of New Zealand, Wellington, New Zealand
| |
Collapse
|
48
|
Nathan DE, Bellgowan JF, Oakes TR, French LM, Nadar SR, Sham EB, Liu W, Riedy G. Assessing Quantitative Changes in Intrinsic Thalamic Networks in Blast and Nonblast Mild Traumatic Brain Injury: Implications for Mechanisms of Injury. Brain Connect 2016; 6:389-402. [PMID: 26956452 DOI: 10.1089/brain.2015.0403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the global war on terror, the increased use of improvised explosive devices has resulted in increased incidence of blast-related mild traumatic brain injury (mTBI). Diagnosing mTBI is both challenging and controversial due to heterogeneity of injury location, trauma intensity, transient symptoms, and absence of focal biomarkers on standard clinical imaging modalities. The goal of this study is to identify a brain biomarker that is sensitive to mTBI injury. Research suggests the thalamus may be sensitive to changes induced by mTBI. A significant number of connections to and from various brain regions converge at the thalamus. In addition, the thalamus is involved in information processing, integration, and regulation of specific behaviors and mood. In this study, changes in task-free thalamic networks as quantified by graph theory measures in mTBI blast (N = 186), mTBI nonblast (N = 80), and controls (N = 21) were compared. Results show that the blast mTBI group had significant hyper-connectivity compared with the controls and nonblast mTBI group. However, after controlling for post-traumatic stress symptoms (PTSS), the blast mTBI group was not different from the controls, but the nonblast mTBI group showed significant hypo-connectivity. The results suggest that there are differences in the mechanisms of injury related to mTBI as reflected in the architecture of the thalamic networks. However, the effect of PTSS and its relationship to mTBI is difficult to distinguish and warrants more research.
Collapse
Affiliation(s)
- Dominic E Nathan
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.,2 North Tide LLC , Dulles, Virginia.,3 Uniformed Services University of the Health Sciences , Bethesda, Maryland
| | - Julie F Bellgowan
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.,2 North Tide LLC , Dulles, Virginia
| | - Terrence R Oakes
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland
| | - Louis M French
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.,4 Center of Neuroscience and Regenerative Medicine (CNRM) , Bethesda, Maryland
| | - Sreenivasan R Nadar
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.,5 Henry M. Jackson Foundation , Bethesda, Maryland
| | - Elyssa B Sham
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.,2 North Tide LLC , Dulles, Virginia
| | - Wei Liu
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.,2 North Tide LLC , Dulles, Virginia
| | - Gerard Riedy
- 1 National Intrepid Center of Excellence (NICoE), Walter Reed National Military Medical Center , Bethesda, Maryland.,3 Uniformed Services University of the Health Sciences , Bethesda, Maryland
| |
Collapse
|
49
|
Abstract
In the 20th century, the complications of head injuries were controlled but not eliminated. The wars of the 21st century turned attention to blast, the instant of impact and the primary injury of concussion. Computer calculations have established that in the first 5 milliseconds after the impact, four independent injuries on the brain are inflicted: 1) impact and its shockwave, 2) deceleration, 3) rotation and 4) skull deformity with vibration (or resonance). The recovery, pathology and symptoms after acute brain trauma have always been something of a puzzle. The variability of these four modes of injury, along with a variable reserve of neurones, explains some of this problem.
Collapse
Affiliation(s)
- G T Martin
- Accident Compensation Corporation , New Zealand
| |
Collapse
|
50
|
Salimi Jazi M, Rezaei A, Azarmi F, Ziejewski M, Karami G. Computational biomechanics of human brain with and without the inclusion of the body under different blast orientation. Comput Methods Biomech Biomed Engin 2015; 19:1019-31. [DOI: 10.1080/10255842.2015.1088525] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|