Experimental and numerical evaluation of the effect of shock waves on the brain.

2010 ◽  
Vol 127 (3) ◽  
pp. 1790-1790
Author(s):  
Albert I. King
Keyword(s):  
Shock Waves ◽  
Numerical Evaluation ◽  
The Brain

Axonal damage and behavioral deficits in rats with repetitive exposure of the brain to laser-induced shock waves: Effects of inter-exposure time

2021 ◽  
Vol 749 ◽  
pp. 135722
Author(s):  
Kosuke Miyai ◽  
Satoko Kawauchi ◽  
Tamaki Kato ◽  
Tetsuo Yamamoto ◽  
Yasuo Mukai ◽  
...  
Keyword(s):  
Shock Waves ◽  
Exposure Time ◽  
Axonal Damage ◽  
Behavioral Deficits ◽  
Repetitive Exposure ◽  
The Brain

Simulations of focused shear shock waves in soft solids and the brain

2014 ◽  
Vol 136 (4) ◽  
pp. 2279-2280
Author(s):  
Bruno Giammarinaro ◽  
François Coulouvrat ◽  
Gianmarco Pinton
Keyword(s):  
Shock Waves ◽  
Soft Solids ◽  
The Brain

A Multi-Scale Finite Element Model for Shock Wave-Induced Axonal Brain Injury

2008 ◽  
Author(s):  
M. Sotudeh-Chafi ◽  
N. Abolfathi ◽  
A. Nick ◽  
V. Dirisala ◽  
G. Karami ◽  
...  
Keyword(s):  
Shock Wave ◽  
Brain Injury ◽  
Shock Waves ◽  
Brain Tissue ◽  
Scale Model ◽  
Micro Scale ◽  
Multi Scale ◽  
Injury Criteria ◽  
Wave Induced ◽  
The Brain

Traumatic brain injuries (TBIs) involve a significant portion of human injuries resulting from a wide range of civilian accidents as well as many military scenarios. Axonal damage is one of the most common and important pathologic features of traumatic brain injury. Axons become brittle when exposed to rapid deformations associated with brain trauma. Accordingly, rapid stretch of axons can damage the axonal cytoskeleton, resulting in a loss of elasticity and impairment of axoplasmic transport. Subsequent swelling of the axon occurs in discrete bulb formations or in elongated varicosities that accumulate organelles. Ultimately, swollen axons may become disconnected [1]. The shock waves generated by a blast, subject all the organs in the head to displacement, shearing and tearing forces. The brain is especially vulnerable to these forces — the fronts of compressed air waves cause rapid forward or backward movements of the head, so that the brain rattles against the inside of the skull. This can cause subdural hemorrhage and contusions. The forces exerted on the brain by shock waves are known to damage axons in the affected areas. This axonal damage begins within minutes of injury, and can continue for hours or days following the injury [2]. Shock waves are also known to damage the brain at the subcellular level, but exactly how remains unclear. Kato et al., [3] described the effects of a small controlled explosion on rats’ brain tissue. They found that high pressure shock waves led to contusions and hemorrhage in both cortical and subcortical brain regions. Based on their result, the threshold for shock wave-induced brain injury is speculated to be under 1 MPa. This is the first report to demonstrate the pressure-dependent effect of shock wave on the histological characteristics of brain tissue. An important step in understanding the primary blast injury mechanism due to explosion is to translate the global head loads to the loading conditions, and consequently damage, of the cells at the local level and to project cell level and tissue level injury criteria towards the level of the head. In order to reach this aim, we have developed a multi-scale non-linear finite element modeling to bridge the micro- and macroscopic scales and establish the connection between microstructure and effective behavior of brain tissue to develop acceptable injury threshold. Part of this effort has been focused on measuring the shock waves created from a blast, and studying the response of the brain model of a human head exposed to such an environment. The Arbitrary Lagrangian Eulerian (ALE) and Fluid/Solid Interactions (FSI) formulation have been used to model the brain-blast interactions. Another part has gone into developing a validated fiber-matrix based micro-scale model of a brain tissue to reproduce the effective response and to capturing local details of the tissue’s deformations causing axonal injury. The micro-model of the axon and matrix is characterized by a transversely isotropic viscoelastic material and the material model is formulated for numerical implementation. Model parameters are fit to experimental frequency response of the storage and loss modulus data obtained and determined using a genetic algorithm (GA) optimizing method. The results from macro-scale model are used in the micro-scale brain tissue to study the effective behavior of this tissue under injury-based loadings. The research involves the development of a tool providing a better understanding of the mechanical behavior of the brain tissue against blast loads and a rational multi-scale approach for driving injury criteria.

Numerical evaluation of steam normal shock waves

1995 ◽  
Vol 110 (1-4) ◽  
pp. 183-197 ◽  
Author(s):  
X. K. Kakatsios
Keyword(s):  
Shock Waves ◽  
Numerical Evaluation ◽  
Normal Shock

Study the Effects of Padding Materials on the Level of the Load in the Brain

2013 ◽  
Author(s):  
Mehdi Salimi Jazi ◽  
Asghar Rezaei ◽  
Ghodrat Karami ◽  
Fardad Azarmi ◽  
Mariusz Ziejewski
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Shock Waves ◽  
Military Service ◽  
Ballistic Impact ◽  
Motor Vehicles ◽  
Common Causes ◽  
The Military ◽  
The Brain

Experiencing a speedy strain or acceleration causes Traumatic Brain Injury (TBI) that can be classified into mild, moderate and severe, based on the level of the injury. Motor vehicles crashes; violence related injuries; collisions in sports; and falls are most common causes of TBI. Moreover in the military service TBI can be happened when soldiers are exposed to shock waves due to blasts or because of ballistic impact.

scholarly journals Shear Shock Waves Observed in the Brain

2017 ◽  
Vol 8 (4) ◽  
Author(s):  
David Espíndola ◽  
Stephen Lee ◽  
Gianmarco Pinton
Keyword(s):  
Shock Waves ◽  
The Brain

scholarly journals Numerical Simulation of Focused Shock Shear Waves in Soft Solids and a Two-Dimensional Nonlinear Homogeneous Model of the Brain

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
B. Giammarinaro ◽  
F. Coulouvrat ◽  
G. Pinton
Keyword(s):  
Shock Wave ◽  
Numerical Methods ◽  
Shock Waves ◽  
Scaling Laws ◽  
Soft Tissues ◽  
Shear Waves ◽  
Homogeneous Model ◽  
Nonlinear Propagation ◽  
Soft Solids ◽  
The Brain

Shear waves that propagate in soft solids, such as the brain, are strongly nonlinear and can develop into shock waves in less than one wavelength. We hypothesize that these shear shock waves could be responsible for certain types of traumatic brain injuries (TBI) and that the spherical geometry of the skull bone could focus shear waves deep in the brain, generating diffuse axonal injuries. Theoretical models and numerical methods that describe nonlinear polarized shear waves in soft solids such as the brain are presented. They include the cubic nonlinearities that are characteristic of soft solids and the specific types of nonclassical attenuation and dispersion observed in soft tissues and the brain. The numerical methods are validated with analytical solutions, where possible, and with self-similar scaling laws where no known solutions exist. Initial conditions based on a human head X-ray microtomography (CT) were used to simulate focused shear shock waves in the brain. Three regimes are investigated with shock wave formation distances of 2.54 m, 0.018 m, and 0.0064 m. We demonstrate that under realistic loading scenarios, with nonlinear properties consistent with measurements in the brain, and when the shock wave propagation distance and focal distance coincide, nonlinear propagation can easily overcome attenuation to generate shear shocks deep inside the brain. Due to these effects, the accelerations in the focal are larger by a factor of 15 compared to acceleration at the skull surface. These results suggest that shock wave focusing could be responsible for diffuse axonal injuries.

Application of shock waves as a treatment modality in the vicinity of the brain and skull

2003 ◽  
Vol 99 (1) ◽  
pp. 156-162 ◽  
Author(s):  
Atsuhiro Nakagawa ◽  
Yasuko Kusaka ◽  
Takayuki Hirano ◽  
Tsutomu Saito ◽  
Reizo Shirane ◽  
...  
Keyword(s):  
Shock Wave ◽  
Shock Waves ◽  
Dura Mater ◽  
Treatment Modality ◽  
Ho:Yag Laser ◽  
Content Type ◽  
Dural Substitute ◽  
Wave Generator ◽  
The Brain ◽  
Fine Print

Object. Shock waves have not previously been used as a treatment modality for lesions in the brain and skull because of the lack of a suitable shock wave source and concerns about safety. Therefore, the authors have performed experiments aimed at developing both a new, compact shock wave generator with a holmium:yttrium-aluminum-garnet (Ho:YAG) laser and a safe method for exposing the surface of the brain to these shock waves. Methods. Twenty male Sprague—Dawley rats were used in this study. In 10 rats, a single shock wave was delivered directly to the brain, whereas the protective effect of inserting a 0.7-mm-thick expanded polytetrafluoroethylene (ePTFE) dural substitute between the dura mater and skull before applying the shock wave was investigated in the other 10 rats. Visualizations on shadowgraphy along with pressure measurements were obtained to confirm that the shock wave generator was capable of conveying waves in a limited volume without harmful effects to the target. The attenuation rates of shock waves administered through a 0.7-mm-thick ePTFE dural substitute and a surgical cottonoid were measured to determine which of these materials was suitable for avoiding propagation of the shock wave beyond the target. Conclusions. Using the shock wave generator with the Ho:YAG laser, a localized shock wave (with a maximum overpressure of 50 bar) can be generated from a small device (external diameter 15 mm, weight 20 g). The placement of a 0.7-mm-thick ePTFE dural substitute over the dura mater reduces the overpressure of the shock wave by 96% and eliminates damage to surrounding tissue in the rat brain. These findings indicate possibilities for applying shock waves in various neurosurgical treatments such as cranioplasty, local drug delivery, embolysis, and pain management.

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