Computer methods in biomechanics and biomedical engineering
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Comput Methods Biomech Biomed Engin · Sep 2021
Effects of a contusion load on spinal cord with different curvatures.
The cervical spine injury is a complicated procedure in the combination of different injury loads and postures. The aim of this study is to investigate the injury mechanism considering different types of cervical curvatures subjected to contusion loads. A finite element model of a cervical spinal cord was constructed. ⋯ A back-to-front load damaged the structure around the central canal and a front-to-back contusion load damaged the anterior horn of the spinal cord at most time. From the view of the maximum stress, the lordotic curvature did not show significant buffering effect. However, the pathological curvature had large areas affected and the lordotic curvature showed some benefits to some degree from the view of stress distribution.
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Comput Methods Biomech Biomed Engin · Aug 2020
Outbreak dynamics of COVID-19 in Europe and the effect of travel restrictions.
For the first time in history, on March 17, 2020, the European Union closed all its external borders in an attempt to contain the spreading of the coronavirus 2019, COVID-19. Throughout two past months, governments around the world have implemented massive travel restrictions and border control to mitigate the outbreak of this global pandemic. However, the precise effects of travel restrictions on the outbreak dynamics of COVID-19 remain unknown. ⋯ Our simulations show that mobility networks of air travel can predict the emerging global diffusion pattern of a pandemic at the early stages of the outbreak. Our results suggest that an unconstrained mobility would have significantly accelerated the spreading of COVID-19, especially in Central Europe, Spain, and France. Ultimately, our network epidemiology model can inform political decision making and help identify exit strategies from current travel restrictions and total lockdown.
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Comput Methods Biomech Biomed Engin · Apr 2019
Comparative StudyBiomechanical comparison of the effects of anterior, posterior and transforaminal lumbar interbody fusion on vibration characteristics of the human lumbar spine.
Previous studies have compared the effects of different interbody fusion approaches on biomechanical responses of the lumbar spine to static loadings. However, very few have dealt with the whole body vibration (WBV) condition that is typically present in vehicles. This study was designed to determine the biomechanical differences among anterior, posterior and transforaminal lumbar interbody fusion (ALIF, PLIF and TLIF) under vertical WBV. ⋯ The endplate stresses in the TLIF model were lower than in the ALIF and PLIF models, but the TLIF generated greater stresses in the screws and rods compared with the ALIF and PLIF. At other levels, a decrease in dynamic responses of the disc bulge, annulus stress and intradiscal pressure was observed in all the fusion models compared with the intact one, but there was no obvious difference in these dynamic responses among the ALIF, PLIF and TLIF models. These findings might be useful in understanding vibration characteristics of the whole lumbar spine after different types of fusion surgery.
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Comput Methods Biomech Biomed Engin · Nov 2017
Numerical study of intrathecal drug delivery to a permeable spinal cord: effect of catheter position and angle.
Intrathecal delivery is a procedure involving the release of therapeutic agents into the cerebrospinal fluid (CSF) hrough a catheter. It holds promise for treating high-impact central nervous system pathologies, for which systemic administration routes are ineffective. In this study we introduce a numerical model able to simultaneously account for solute transport in the fluid and in the spinal cord. ⋯ We used clinically representative data for the drug injection speed and dose rate, and scaled drug diffusion/penetration properties to obtain observable effects during the considered simulation time. Based on our limited set of working parameters, lateral injection perpendicular to the cord turned out to be more effective than other configurations. Even if the adopted scaling does not allow for a direct clinical translation (a wider parametric assessment of the importance of CSF flow, geometry and diffusion properties is needed), it did not weaken our numerical approach, which can be used to systematically investigate multiple catheter, geometry and fluid/tissue properties configurations, thus paving the way for therapy control.
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Comput Methods Biomech Biomed Engin · Apr 2017
Sensitivity of lumbar spine response to follower load and flexion moment: finite element study.
The follower load (FL) combined with moments is commonly used to approximate flexed/extended posture of the lumbar spine in absence of muscles in biomechanical studies. There is a lack of consensus as to what magnitudes simulate better the physiological conditions. Considering the in-vivo measured values of the intradiscal pressure (IDP), intervertebral rotations (IVRs) and the disc loads, sensitivity of these spinal responses to different FL and flexion moment magnitudes was investigated using a 3D nonlinear finite element (FE) model of ligamentous lumbosacral spine. ⋯ The FL magnitude had reverse effect on the IDP and disc force. Thus, magnitude for FL or flexion that minimizes the deviation of all the spinal parameters together from the in-vivo data can vary. To obtain reasonable compromise between the IDP and disc force, our findings recommend that FL of low magnitude must be combined with flexion moment of high intensity and vice versa.