scholarly journals In vitro and Numerical Simulation of Blood Removal from Cerebrospinal Fluid: Comparison of Lumbar Drain to Neurapheresis Therapy

2020 ◽  
Author(s):  
Mohammadreza Khani ◽  
Lucas Sass ◽  
M. Keith Sharp ◽  
Aaron McCabe ◽  
Laura Zitella Verbick ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Subarachnoid Space ◽  
Cfd Model ◽  
Tracer Concentration ◽  
Steady Streaming ◽  
Lumbar Drain ◽  
Spinal Subarachnoid Space ◽  
Subject Specific ◽  
The Impact

Abstract Background: Blood removal from cerebrospinal fluid (CSF) in post-subarachnoid hemorrhage patients may reduce the risk of related secondary brain injury. We formulated a computational fluid dynamics (CFD) model to investigate the impact of a dual-lumen catheter-based CSF filtration system, called Neurapheresis TM therapy, on blood removal from CSF compared to lumbar drain. Methods: A subject-specific multiphase CFD model of CSF system-wide solute transport was constructed based on MRI measurements. The Neurapheresis catheter geometry was added to the model within the spinal subarachnoid space. Neurapheresis flow aspiration and return rate was 2.0 and 1.8 (mL/min), versus 0.2 (mL/min) drainage for lumbar drain. Blood was modeled as a bulk fluid phase within CSF with a 10% initial tracer concentration and identical viscosity and density as CSF. Subject-specific oscillatory CSF flow was applied at the model inlet. The dura and spinal cord geometry were considered to be stationary. Spatial-temporal tracer concentration was quantified based on time-average steady-streaming velocities throughout the domain under Neurapheresis therapy and lumbar drain. To help verify CFD results, an optically clear in vitro CSF model was constructed with fluorescein used as a blood surrogate. Quantitative comparison of numerical and in vitro results was performed by linear regression of spatial-temporal tracer concentration over 24-hours. Results: After 24-hours, tracer concentration was reduced to 4.9% under Neurapheresis therapy compared to 6.5% under lumbar drain. Tracer clearance was most rapid between the catheter aspiration and return ports. Neurapheresis therapy was found to have a greater impact on steady-streaming compared to lumbar drain. Steady-streaming in the cranial SAS was ~50X smaller than in the spinal subarachnoid space for both cases. CFD results were strongly correlated with the in vitro spatial-temporal tracer concentration under Neurapheresis therapy (R 2 =0.89 with +2.13% and -1.93% tracer concentration confidence interval). Conclusion: A subject-specific CFD model of CSF system-wide solute transport was used to investigate the impact of Neurapheresis therapy on tracer removal from CSF compared to lumbar drain over a 24-hour period. Neurapheresis therapy was found to substantially increase tracer clearance compared to lumbar drain. The multiphase CFD results were verified by in vitro fluorescein tracer experiments.

scholarly journals In vitro and Numerical Simulation of Blood Removal from Cerebrospinal Fluid: Comparison of Lumbar Drain to Neurapheresis Therapy

2020 ◽  
Author(s):  
Mohammadreza Khani ◽  
Lucas Sass ◽  
M. Keith Sharp ◽  
Aaron McCabe ◽  
Laura Zitella Verbick ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Subarachnoid Space ◽  
Cfd Model ◽  
Tracer Concentration ◽  
Steady Streaming ◽  
Lumbar Drain ◽  
Spinal Subarachnoid Space ◽  
Subject Specific ◽  
The Impact

Abstract Background: Blood removal from cerebrospinal fluid (CSF) in post-subarachnoid hemorrhage patients may reduce the risk of related secondary brain injury. We formulated a computational fluid dynamics (CFD) model to investigate the impact of a dual-lumen catheter-based CSF filtration system, called Neurapheresis TM therapy, on blood removal from CSF compared to lumbar drain. Methods: A subject-specific multiphase CFD model of CSF system-wide solute transport was constructed based on MRI measurements. The Neurapheresis catheter geometry was added to the model within the spinal subarachnoid space. Neurapheresis flow aspiration and return rate was 2.0 and 1.8 (mL/min), versus 0.2 (mL/min) drainage for lumbar drain. Blood was modeled as a bulk fluid phase within CSF with a 10% initial tracer concentration and identical viscosity and density as CSF. Subject-specific oscillatory CSF flow was applied at the model inlet. The dura and spinal cord geometry were considered to be stationary. Spatial-temporal tracer concentration was quantified based on time-average steady-streaming velocities throughout the domain under Neurapheresis therapy and lumbar drain. To help verify CFD results, an optically clear in vitro CSF model was constructed with fluorescein used as a blood surrogate. Quantitative comparison of numerical and in vitro results was performed by linear regression of spatial-temporal tracer concentration over 24-hours. Results: After 24-hours, tracer concentration was reduced to 4.9% under Neurapheresis therapy compared to 6.5% under lumbar drain. Tracer clearance was most rapid between the catheter aspiration and return ports. Neurapheresis therapy was found to have a greater impact on steady-streaming compared to lumbar drain. Steady-streaming in the cranial SAS was ~50X smaller than in the spinal subarachnoid space for both cases. CFD results were strongly correlated with the in vitro spatial-temporal tracer concentration under Neurapheresis therapy (R 2 =0.89 with +2.13% and -1.93% tracer concentration confidence interval). Conclusion: A subject-specific CFD model of CSF system-wide solute transport was used to investigate the impact of Neurapheresis therapy on tracer removal from CSF compared to lumbar drain over a 24-hour period. Neurapheresis therapy was found to substantially increase tracer clearance compared to lumbar drain. The multiphase CFD results were verified by in vitro fluorescein tracer experiments.

scholarly journals In vitro and Numerical Simulation of Blood Removal from Cerebrospinal Fluid: Comparison of Lumbar Drain to Neurapheresis Therapy

2020 ◽  
Author(s):  
Mohammadreza Khani ◽  
Lucas Sass ◽  
M. Keith Sharp ◽  
Aaron McCabe ◽  
Laura Zitella Verbick ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Solute Transport ◽  
Cfd Model ◽  
Tracer Concentration ◽  
Steady Streaming ◽  
Lumbar Drain ◽  
Subject Specific ◽  
Multiphase Cfd ◽  
The Impact

Abstract Background: Blood removal from cerebrospinal fluid (CSF) in post-subarachnoid hemorrhage patients may reduce the risk of related secondary brain injury. We formulated a computational fluid dynamics (CFD) model to investigate the impact of a dual-lumen catheter-based CSF filtration system, called NeurapheresisTM therapy, on blood removal from CSF compared to lumbar drain. Methods: A subject-specific multiphase CFD model of CSF system-wide solute transport was constructed based on MRI measurements. The Neurapheresis catheter geometry was added to the model within the spinal subarachnoid space (SAS). Neurapheresis flow aspiration and return rate was 2.0 and 1.8 mL/min, versus 0.2 mL/min drainage for lumbar drain. Blood was modeled as a bulk fluid phase within CSF with a 10% initial tracer concentration and identical viscosity and density as CSF. Subject-specific oscillatory CSF flow was applied at the model inlet. The dura and spinal cord geometry were considered to be stationary. Spatial-temporal tracer concentration was quantified based on time-average steady-streaming velocities throughout the domain under Neurapheresis therapy and lumbar drain. To help verify CFD results, an optically clear in vitro CSF model was constructed with fluorescein used as a blood surrogate. Quantitative comparison of numerical and in vitro results was performed by linear regression of spatial-temporal tracer concentration over 24-hours.Results: After 24-hours, tracer concentration was reduced to 4.9% under Neurapheresis therapy compared to 6.5% under lumbar drain. Tracer clearance was most rapid between the catheter aspiration and return ports. Neurapheresis therapy was found to have a greater impact on steady-streaming compared to lumbar drain. Steady-streaming in the cranial SAS was ~50X smaller than in the spinal SAS for both cases. CFD results were strongly correlated with the in vitro spatial-temporal tracer concentration under Neurapheresis therapy (R2=0.89 with +2.13% and -1.93% tracer concentration confidence interval). Conclusion: A subject-specific CFD model of CSF system-wide solute transport was used to investigate the impact of Neurapheresis therapy on tracer removal from CSF compared to lumbar drain over a 24-hour period. Neurapheresis therapy was found to substantially increase tracer clearance compared to lumbar drain. The multiphase CFD results were verified by in vitro fluorescein tracer experiments.

scholarly journals Anthropomorphic Model of Intrathecal Cerebrospinal Fluid Dynamics Within the Spinal Subarachnoid Space: Spinal Cord Nerve Roots Increase Steady-Streaming

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Mohammadreza Khani ◽  
Lucas R. Sass ◽  
Tao Xing ◽  
M. Keith Sharp ◽  
Olivier Balédent ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Spinal Cord ◽  
Cerebrospinal Fluid ◽  
Cfd Model ◽  
Csf Flow ◽  
Nerve Roots ◽  
Csf Dynamics ◽  
Steady Streaming ◽  
Spinal Subarachnoid Space ◽  
The Impact

Cerebrospinal fluid (CSF) dynamics are thought to play a vital role in central nervous system (CNS) physiology. The objective of this study was to investigate the impact of spinal cord (SC) nerve roots (NR) on CSF dynamics. A subject-specific computational fluid dynamics (CFD) model of the complete spinal subarachnoid space (SSS) with and without anatomically realistic NR and nonuniform moving dura wall deformation was constructed. This CFD model allowed detailed investigation of the impact of NR on CSF velocities that is not possible in vivo using magnetic resonance imaging (MRI) or other noninvasive imaging methods. Results showed that NR altered CSF dynamics in terms of velocity field, steady-streaming, and vortical structures. Vortices occurred in the cervical spine around NR during CSF flow reversal. The magnitude of steady-streaming CSF flow increased with NR, in particular within the cervical spine. This increase was located axially upstream and downstream of NR due to the interface of adjacent vortices that formed around NR.

scholarly journals Impact of Neurapheresis System on Intrathecal Cerebrospinal Fluid Dynamics: A Computational Fluid Dynamics Study

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Mohammadreza Khani ◽  
Lucas R. Sass ◽  
Aaron R. McCabe ◽  
Laura M. Zitella Verbick ◽  
Shivanand P. Lad ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cerebrospinal Fluid ◽  
Removal Rate ◽  
Maximum Flow ◽  
Cfd Model ◽  
Flow Loop ◽  
Steady Streaming ◽  
Lumbar Drain ◽  
The Impact

Abstract It has been hypothesized that early and rapid filtration of blood from cerebrospinal fluid (CSF) in postsubarachnoid hemorrhage patients may reduce hospital stay and related adverse events. In this study, we formulated a subject-specific computational fluid dynamics (CFD) model to parametrically investigate the impact of a novel dual-lumen catheter-based CSF filtration system, the Neurapheresis™ system (Minnetronix Neuro, Inc., St. Paul, MN), on intrathecal CSF dynamics. The operating principle of this system is to remove CSF from one location along the spine (aspiration port), externally filter the CSF routing the retentate to a waste bag, and return permeate (uncontaminated CSF) to another location along the spine (return port). The CFD model allowed parametric simulation of how the Neurapheresis system impacts intrathecal CSF velocities and steady–steady streaming under various Neurapheresis flow settings ranging from 0.5 to 2.0 ml/min and with a constant retentate removal rate of 0.2 ml/min simulation of the Neurapheresis system were compared to a lumbar drain simulation with a typical CSF removal rate setting of 0.2 ml/min. Results showed that the Neurapheresis system at a maximum flow of 2.0 ml/min increased average steady streaming CSF velocity 2× in comparison to lumbar drain (0.190 ± 0.133 versus 0.093 ± 0.107 mm/s, respectively). This affect was localized to the region within the Neurapheresis flow loop. The mean velocities introduced by the flow loop were relatively small in comparison to normal cardiac-induced CSF velocities.

Three-Dimensional Computational Modeling of Subject-Specific Cerebrospinal Fluid Flow in the Subarachnoid Space

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Sumeet Gupta ◽  
Michaela Soellinger ◽  
Peter Boesiger ◽  
Dimos Poulikakos ◽  
Vartan Kurtcuoglu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cerebrospinal Fluid ◽  
Subarachnoid Space ◽  
Three Dimensional ◽  
Volumetric Flow Rate ◽  
Cerebrospinal Fluid Flow ◽  
Spinal Subarachnoid Space ◽  
Subject Specific ◽  
Foramen Of Luschka

This study aims at investigating three-dimensional subject-specific cerebrospinal fluid (CSF) dynamics in the inferior cranial space, the superior spinal subarachnoid space (SAS), and the fourth cerebral ventricle using a combination of a finite-volume computational fluid dynamics (CFD) approach and magnetic resonance imaging (MRI) experiments. An anatomically accurate 3D model of the entire SAS of a healthy volunteer was reconstructed from high resolution T2 weighted MRI data. Subject-specific pulsatile velocity boundary conditions were imposed at planes in the pontine cistern, cerebellomedullary cistern, and in the spinal subarachnoid space. Velocimetric MRI was used to measure the velocity field at these boundaries. A constant pressure boundary condition was imposed at the interface between the aqueduct of Sylvius and the fourth ventricle. The morphology of the SAS with its complex trabecula structures was taken into account through a novel porous media model with anisotropic permeability. The governing equations were solved using finite-volume CFD. We observed a total pressure variation from −42Pato40Pa within one cardiac cycle in the investigated domain. Maximum CSF velocities of about 15cm∕s occurred in the inferior section of the aqueduct, 14cm∕s in the left foramen of Luschka, and 9cm∕s in the foramen of Magendie. Flow velocities in the right foramen of Luschka were found to be significantly lower than in the left, indicating three-dimensional brain asymmetries. The flow in the cerebellomedullary cistern was found to be relatively diffusive with a peak Reynolds number (Re)=72, while the flow in the pontine cistern was primarily convective with a peak Re=386. The net volumetric flow rate in the spinal canal was found to be negligible despite CSF oscillation with substantial amplitude with a maximum volumetric flow rate of 109ml∕min. The observed transient flow patterns indicate a compliant behavior of the cranial subarachnoid space. Still, the estimated deformations were small owing to the large parenchymal surface. We have integrated anatomic and velocimetric MRI data with computational fluid dynamics incorporating the porous SAS morphology for the subject-specific reconstruction of cerebrospinal fluid flow in the subarachnoid space. This model can be used as a basis for the development of computational tools, e.g., for the optimization of intrathecal drug delivery and computer-aided evaluation of cerebral pathologies such as syrinx development in syringomelia.

scholarly journals On the bulk motion of the cerebrospinal fluid in the spinal canal

2018 ◽  
Vol 841 ◽  
pp. 203-227 ◽  
Author(s):  
A. L. Sánchez ◽  
C. Martínez-Bazán ◽  
C. Gutiérrez-Montes ◽  
E. Criado-Hidalgo ◽  
G. Pawlak ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Subarachnoid Space ◽  
Spinal Canal ◽  
Lumbar Region ◽  
Leading Order ◽  
Steady Streaming ◽  
Viscous Forces ◽  
Recirculating Flow ◽  
Radiological Measurements

Radionuclide scanning images published inNatureby Di Chiro in 1964 showed a downward migration along the spinal canal of particle tracers injected in the brain ventricles while also showing an upward flow of tracers injected in the lumbar region of the canal. These observations, since then corroborated by many radiological measurements, have been the basis for the hypothesis that there must be an active circulation mechanism associated with the transport of cerebrospinal fluid (CSF) deep down into the spinal canal and subsequently returning a portion back to the cranial vault. However, to date, there has been no physical explanation for the mechanism responsible for the establishment of such a bulk recirculating motion. To investigate the origin and characteristics of this recirculating flow, we have analyzed the motion of the CSF in the subarachnoid space of the spinal canal. Our analysis accounts for the slender geometry of the spinal canal, the small compliance of the dura membrane enclosing the CSF in the canal, and the fact that the CSF is confined to a thin annular subarachnoid space surrounding the spinal cord. We apply this general formulation to study the characteristics of the flow generated in a simplified model of the spinal canal consisting of a slender compliant cylindrical pipe with a coaxial cylindrical inclusion, closed at its distal end, and subjected to small periodic pressure pulsations at its open entrance. We show that the balance between the local acceleration and viscous forces produces a leading-order flow consisting of pure oscillatory motion with axial velocities on the order of a few centimetres per second and amplitudes monotonically decreasing along the length of the canal. We then demonstrate that the nonlinear term associated with the convective acceleration contributes to a second-order correction consisting of a steady streaming that generates a bulk recirculating motion of the CSF along the length of the canal with characteristic velocities two orders of magnitude smaller than the leading-order oscillatory flow. The results of the analysis of this idealized geometry of the spinal canal are shown to be in good agreement not only with experimental measurements in anin-vitromodel but also with radiological measurements conducted in human adults.

Increased Intracranial Pressure

1981 ◽  
Vol 2 (9) ◽  
pp. 269-276
Author(s):  
John F. Griffith ◽  
Jimmy C. Brasfield
Keyword(s):  
Cerebrospinal Fluid ◽  
Intracranial Pressure ◽  
Subarachnoid Space ◽  
Buffering Capacity ◽  
Raised Intracranial Pressure ◽  
Cranial Cavity ◽  
Increased Intracranial Pressure ◽  
Underlying Process ◽  
Spinal Subarachnoid Space ◽  
Rate Of Absorption

The infant or child with increasing pressure within the cranial cavity must be identified early and treated promptly in order to prevent serious complications or death. When the pressure elevation is gradual it is frequently well tolerated, and the patient may seem deceptively well. There is a critical point, however, beyond which any further increase in pressure leads to a catastrophic deterioration in the patient's condition.1 When this occurs, the outlook for quality survival is poor despite the best therapy. Unfortunately, this can occur when the underlying process is benign and would have been reversible if recognized and treated promptly. For prompt recognition and treatment, the physician must be familiar with the pathophysiology of raised intracranial pressure. PATHOPHYSIOLOGY The intracranial compartment contains blood vessels, cerebrospinal fluid (CSF), brain, and leptomeninges which include the rigid dural membranes forming the falx and tentorium. Whenever there is an increase in the volume of any one of these intracranial components (brain, CSF, blood) there must be a corresponding reduction in the size of the others in order for the intracranial pressure to remain normal. This type of compensation or buffering capacity is particularly important in the early stages of intracranial disease. As the pressure mounts from any type of mass lesion, the CSF is displaced caudally into the spinal subarachnoid space and there is a corresponding increase in the rate of absorption of CSF.2

scholarly journals Cerebrospinal Fluid Pulsation Stress Promotes the Angiogenesis of Tissue-Engineered Laminae

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Linli Li ◽  
Yiqun He ◽  
Han Tang ◽  
Wei Mao ◽  
Haofei Ni ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Cerebrospinal Fluid ◽  
Engineering Technology ◽  
Expression Levels ◽  
Fluid Pulsation ◽  
Endothelial Growth Factor ◽  
The Impact

Background. Angiogenesis is a prerequisite step to achieve the success of bone regeneration by tissue engineering technology. Previous studies have shown the role of cerebrospinal fluid pulsation (CSFP) stress in the reconstruction of tissue-engineered laminae. In this study, we investigated the role of CSFP stress in the angiogenesis of tissue-engineered laminae. Methods. For the in vitro study, a CSFP bioreactor was used to investigate the impact of CSFP stress on the osteogenic mesenchymal stem cells (MSCs). For the in vivo study, forty-eight New Zealand rabbits were randomly divided into the CSFP group and the Non-CSFP group. Tissue-engineered laminae (TEL) was made by hydroxyapatite-collagen I scaffold and osteogenic MSCs and then implanted into the lamina defect in the two groups. The angiogenic and osteogenic abilities of newborn laminae were examined with histological staining, qRT-PCR, and radiological analysis. Results. The in vitro study showed that CSFP stress could promote the vascular endothelial growth factor A (VEGF-A) expression levels of osteogenic MSCs. In the animal study, the expression levels of angiogenic markers in the CSFP group were higher than those in the Non-CSFP group; moreover, in the CSFP group, their expression levels on the dura mater surface, which are closer to the CSFP stress stimulation, were also higher than those on the paraspinal muscle surface. The expression levels of osteogenic markers in the CSFP group were also higher than those in the Non-CSFP group. Conclusion. CSFP stress could promote the angiogenic ability of osteogenic MSCs and thus promote the angiogenesis of tissue-engineered laminae. The pretreatment of osteogenic MSC with a CSFP bioreactor may have important implications for vertebral lamina reconstruction with a tissue engineering technique.

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