Mechanisms of tensile failure of cerebrospinal fluid in blast traumatic brain injury

Yu, Xiancheng; Azor, Adriana; Sharp, David J.; Ghajari, Mazdak

doi:10.1016/j.eml.2020.100739

Cited by 17 publications

(21 citation statements)

References 33 publications

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“…Furthermore, axonal properties such as orientation and location, myelination and length predict the likelihood of axonal injury, with unmyelinated long axons being more vulnerable ( Reeves et al , 2005 ; Staal and Vickers, 2011 ; Marion et al , 2018 ). Differences in the mechanical properties of white/grey matter and CSF compartments also influence injury, with forces concentrated at tissue interfaces ( Drew and Drew, 2004 ; Cloots et al , 2013 ; Yu et al ., 2020 ).…”

Section: Introductionmentioning

confidence: 99%

From biomechanics to pathology: predicting axonal injury from patterns of strain after traumatic brain injury

Donat

Lopez

Sastre

et al. 2021

Brain

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The relationship between biomechanical forces and neuropathology is key to understanding traumatic brain injury. White matter tracts are damaged by high shear forces during impact, resulting in axonal injury, a key determinant of long-term clinical outcomes. However, the relationship between biomechanical forces and patterns of white matter injuries, associated with persistent diffusion MRI abnormalities, is poorly understood. This limits the ability to predict the severity of head injuries and the design of appropriate protection. Our previously developed human finite element model of head injury predicted the location of post-traumatic neurodegeneration. A similar rat model now allows us to experimentally test whether strain patterns calculated by the model predicts in vivo MRI and histology changes. Using a controlled cortical impact, mild and moderate injuries (1 and 2 mm) were performed. Focal and axonal injuries were quantified with volumetric and diffusion 9.4 T MRI at 2 weeks post injury. Detailed analysis of the corpus callosum was conducted using multi-shell diffusion MRI and histopathology. Microglia and astrocyte density, including process parameters, along with white matter structural integrity and neurofilament expression were determined by quantitative immunohistochemistry. Linear mixed effects regression analyses for strain and strain rate with the employed outcome measures were used to ascertain how well immediate biomechanics could explain MRI and histology changes. The spatial pattern of mechanical strain and strain rate in the injured cortex shows good agreement with the probability maps of focal lesions derived from volumetric MRI. Diffusion metrics showed abnormalities in the corpus callosum, indicating white matter changes in the segments subjected to high strain, as predicted by the model. The same segments also exhibited a severity-dependent increase in glia cell density, white matter thinning and reduced neurofilament expression. Linear mixed effects regression analyses showed that mechanical strain and strain rate were significant predictors of in vivo MRI and histology changes. Specifically, strain and strain rate respectively explained 33% and 28% of the reduction in fractional anisotropy, 51% and 29% of the change in neurofilament expression and 51% and 30% of microglia density changes. The work provides evidence that strain and strain rate in the first milliseconds after injury are important factors in determining patterns of glial and axonal injury and serve as experimental validators of our computational model of traumatic brain injury. Our results provide support for the use of this model in understanding the relationship of biomechanics and neuropathology and can guide the development of head protection systems, such as airbags and helmets.

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Section: Introductionmentioning

confidence: 99%

From biomechanics to pathology: predicting axonal injury from patterns of strain after traumatic brain injury

Donat

Lopez

Sastre

et al. 2021

Brain

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“…This is because when fluid cavitates, the pressure will not be further dropped, but kept at a level, called cavitation threshold or cut-off pressure ( Bustamante et al, 2018 ). Previous computational studies have used different cut-off pressures for the CSF material ( Panzer et al, 2012 ; Zhou et al, 2018 ; Yu et al, 2020 ; Yu and Ghajari, 2022 ). As the cavitation threshold of the CSF surrogate in this study was unknown, we did not include a cut-off pressure in the CSF material model, which led to further drop of the predicted negative pressure compared to the experiments.…”

Section: Resultsmentioning

confidence: 99%

Non-Lethal Blasts can Generate Cavitation in Cerebrospinal Fluid While Severe Helmeted Impacts Cannot: A Novel Mechanism for Blast Brain Injury

Nguyen

et al. 2022

Front. Bioeng. Biotechnol.

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Cerebrospinal fluid (CSF) cavitation is a likely physical mechanism for producing traumatic brain injury (TBI) under mechanical loading. In this study, we investigated CSF cavitation under blasts and helmeted impacts which represented loadings in battlefield and road traffic/sports collisions. We first predicted the human head response under the blasts and impacts using computational modelling and found that the blasts can produce much lower negative pressure at the contrecoup CSF region than the impacts. Further analysis showed that the pressure waves transmitting through the skull and soft tissue are responsible for producing the negative pressure at the contrecoup region. Based on this mechanism, we hypothesised that blast, and not impact, can produce CSF cavitation. To test this hypothesis, we developed a one-dimensional simplified surrogate model of the head and exposed it to both blasts and impacts. The test results confirmed the hypothesis and computational modelling of the tests validated the proposed mechanism. These findings have important implications for prevention and diagnosis of blast TBI.

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“…The FE modeling technique of using the shared nodes at the interfaces is also widely used in modeling the human brain and face. 29,30 It should be noted that the SSV, the GSV and the MPV are the most commonly diseased and associated with varicose veins in the lower limb 31 and, thus, they are chosen to be investigated in the present study. The mean radius of the three veins is approximately 2.39 AE 0.15 mm in the present subject.…”

Section: Generation Of the Finite Element Mesh Of The Calfmentioning

confidence: 99%

Evaluating the biomechanical interaction between the medical compression stocking and human calf using a highly anatomical fidelity three-dimensional finite element model

Lyu

Zhang

Cheng

et al. 2020

Textile Research Journal

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The beneficial effects of the medical compression stocking (MCS) in the treatment of venous disorders of the human lower limb have been recognized. However, the effectiveness of the MCS on the internal tissues of the lower limb has not been properly evaluated. The aim of the present study was to shed light on the mechanism of compression therapy using a highly anatomical fidelity three-dimensional finite element (FE) model. A FE calf model of a 40-year-old female was created from magnetic resonance images, in which the bones, the muscle groups, three veins (the great saphenous vein, medial peroneal vein and small saphenous vein), the subcutaneous tissues (fascia) and the skin were reconstructed. The model was validated using experimental data collected in-house, and then the influence of different levels of external compression and the biomechanical effect of the MCS under the pathological conditions were investigated. The results showed that the pressure at the skin–stocking interface was largely influenced by the external compression pressure with an increase of up to 54.98%, while the pressure was neither influenced by the impairment of the muscular tissues nor by the impairment of the calf veins, with the largest change of just 5.63%. The trans-mural pressure was increased more by the impairment of the calf veins than by the impairment of the muscular tissues. The volume reductions in the calf veins were not evenly distributed. The present study provides some guidance on compression therapy.

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Mechanisms of tensile failure of cerebrospinal fluid in blast traumatic brain injury

Cited by 17 publications

References 33 publications

From biomechanics to pathology: predicting axonal injury from patterns of strain after traumatic brain injury

From biomechanics to pathology: predicting axonal injury from patterns of strain after traumatic brain injury

Non-Lethal Blasts can Generate Cavitation in Cerebrospinal Fluid While Severe Helmeted Impacts Cannot: A Novel Mechanism for Blast Brain Injury

Evaluating the biomechanical interaction between the medical compression stocking and human calf using a highly anatomical fidelity three-dimensional finite element model

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