Mechanical indicators of injury severity are decreased with increased thecal sac dimension in a bench-top model of contusion type spinal cord injury

Jones, Claire F.; Cripton, Peter A.

doi:10.1016/j.jbiomech.2012.01.025

Cited by 8 publications

(11 citation statements)

References 45 publications

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“…This is likely attributed to the lack of longitudinal tension in the surrogate cord complex and lower CSF pressures than the in vivo system. 37 The peak forces in the NHP FE contusion models were similar to the highest impact forces in the in vivo models. In vivo peak forces and transferred energy were highly correlated with each other.…”

Section: Post-impact Analysis and Iterative Model Refinementmentioning

confidence: 58%

“…The surrogate model of the NHP spinal cord, CSF, and dura was constructed following an approach defined for a surrogate cord model of the human spinal cord. 37 The spinal cord was cast from two part silicone, (QM Skin 30, Quantum Silicones, Richmond, VA) and the dura mater was simulated by polyethylene lay flat tubing that was vacuum sealed at a length of 150 mm and diameter of 12 mm.…”

Section: Defining a Baseline For Impactmentioning

confidence: 99%

“…Several groups have established validated approaches to simulate spinal cord injury through FE methods [32][33][34][35][36] and physical surrogate models. 37,38 FE models have demonstrated a strong correlation between tissue level stress, strain, and structural damage in rat models of contusion and dislocation 34,35 and guinea pig white matter lesions. 32,33 The relationship between impact mechanics and tissue damage demonstrate that FE models can be valuable in predicting approximate injury severity for different impacts.…”

Section: Introductionmentioning

confidence: 99%

“…36 Surrogate models have also quantified the effects of the amount of CSF and dural thickness on impact mechanics. 37 Results from tests conducted on surrogate cords highlight the sensitivity of impact mechanics to spinal cord and column morphology. Therefore, developing models that accurately replicate the morphology of the NHP will help to identify mechanical parameters needed to generate consistent injuries with similar behavioral and anatomical outcomes.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Design and Analysis of a Unilateral Cervical Spinal Cord Contusion Injury Model in Non-Human Primates

Sparrey

Salegio

Camisa

et al. 2016

Journal of Neurotrauma

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Non-human primate (NHP) models of spinal cord injury better reflect human injury and provide a better foundation to evaluate potential treatments and functional outcomes. We combined finite element (FE) and surrogate models with impact data derived from in vivo experiments to define the impact mechanics needed to generate a moderate severity unilateral cervical contusion injury in NHPs (Macaca mulatta). Three independent variables (impactor displacement, alignment, and pre-load) were examined to determine their effects on tissue level stresses and strains. Mechanical measures of peak force, peak displacement, peak energy, and tissue stiffness were analyzed as potential determinants of injury severity. Data generated from FE simulations predicted a lateral shift of the spinal cord at high levels of compression (>64%) during impact. Submillimeter changes in mediolateral impactor position over the midline increased peak impact forces (>50%). Surrogate cords established a 0.5 N pre-load protocol for positioning the impactor tip onto the dural surface to define a consistent dorsoventral baseline position before impact, which corresponded with cerebrospinal fluid displacement and entrapment of the spinal cord against the vertebral canal. Based on our simulations, impactor alignment and pre-load were strong contributors to the variable mechanical and functional outcomes observed in in vivo experiments. Peak displacement of 4 mm after a 0.5N pre-load aligned 0.5-1.0 mm over the midline should result in a moderate severity injury; however, the observed peak force and calculated peak energy and tissue stiffness are required to properly characterize the severity and variability of in vivo NHP contusion injuries.

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Section: Post-impact Analysis and Iterative Model Refinementmentioning

confidence: 58%

Section: Defining a Baseline For Impactmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Mechanical Design and Analysis of a Unilateral Cervical Spinal Cord Contusion Injury Model in Non-Human Primates

Sparrey

Salegio

Camisa

et al. 2016

Journal of Neurotrauma

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show abstract

“…Note that in the present study, no CSF leakage was observed between catheter insertion and application of glue. Several recent studies have emphasised the importance of incorporating the CSF layer into experimental models of SCI, as it plays an important biomechanical role in transmitting forces to the spinal cord [38,39].…”

Section: Discussionmentioning

confidence: 99%

Rat model of spinal cord injury preserving dura mater integrity and allowing measurements of cerebrospinal fluid pressure and spinal cord blood flow

et al. 2013

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Purposes Cerebrospinal fluid (CSF) pressure elevation may worsen spinal cord ischaemia after spinal cord injury (SCI). We developed a rat model to investigate relationships between CSF pressure and spinal cord blood flow (SCBF). Methods Male Wistar rats had SCI induced at Th10 (n = 7) or a sham operation (n = 10). SCBF was measured using laser-Doppler and CSF pressure via a sacral catheter. Dural integrity was assessed using subdural methyleneblue injection (n = 5) and myelography (n = 5). Results The SCI group had significantly lower SCBF (p \ 0.0001) and higher CSF pressure (p \ 0.0001) values compared to the sham-operated group. Sixty minutes after SCI or sham operation, CSF pressure was 8.6 ± 0.4 mmHg in the SCI group versus 5.5 ± 0.5 mmHg in the shamoperated group. No dural tears were found after SCI. Conclusion Our rat model allows SCBF and CSF pressure measurements after induced SCI. After SCI, CSF pressure significantly increases.

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Comparison of numerical methods for cerebrospinal fluid representation and fluid–structure interaction during transverse impact of a finite element spinal cord model

Rycman

McLachlin

Cronin

2022

Numer Methods Biomed Eng

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Spinal cord impacts can have devastating consequences. Computational models can investigate such impacts but require biofidelic numerical representations of the neural tissues and fluid–structure interaction with cerebrospinal fluid. Achieving this biofidelity is challenging, particularly for efficient implementation of the cerebrospinal fluid in full computational human body models. The goal of this study was to assess the biofidelity and computational efficiency of fluid–structure interaction methods representing the cerebrospinal fluid interacting with the spinal cord, dura, and pia mater using experimental pellet impact test data from bovine spinal cords. Building on an existing finite element model of the spinal cord and pia mater, an orthotropic hyperelastic constitutive model was proposed for the dura mater and fit to literature data. The dura mater and cerebrospinal fluid were integrated with the existing finite element model to assess four fluid–structure interaction methods under transverse impact: Lagrange, pressurized volume, smoothed particle hydrodynamics, and arbitrary Lagrangian–Eulerian. The Lagrange method resulted in an overly stiff mechanical response, whereas the pressurized volume method over‐predicted compression of the neural tissues. Both the smoothed particle hydrodynamics and arbitrary Lagrangian–Eulerian methods were able to effectively model the impact response of the pellet on the dura mater, outflow of the cerebrospinal fluid, and compression of the spinal cord; however, the arbitrary Lagrangian–Eulerian compute time was approximately five times higher than smoothed particle hydrodynamics. Crucial to implementation in human body models, the smoothed particle hydrodynamics method provided a computationally efficient and representative approach to model spinal cord fluid–structure interaction during transverse impact.

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Mechanical indicators of injury severity are decreased with increased thecal sac dimension in a bench-top model of contusion type spinal cord injury

Cited by 8 publications

References 45 publications

Mechanical Design and Analysis of a Unilateral Cervical Spinal Cord Contusion Injury Model in Non-Human Primates

Mechanical Design and Analysis of a Unilateral Cervical Spinal Cord Contusion Injury Model in Non-Human Primates

Rat model of spinal cord injury preserving dura mater integrity and allowing measurements of cerebrospinal fluid pressure and spinal cord blood flow

Comparison of numerical methods for cerebrospinal fluid representation and fluid–structure interaction during transverse impact of a finite element spinal cord model

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