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Alaminos-Quesada J, Gutiérrez-Montes C, Coenen W, Sánchez A. Effects of buoyancy on the dispersion of drugs released intrathecally in the spinal canal. JOURNAL OF FLUID MECHANICS 2024; 985:A20. [PMID: 38774672 PMCID: PMC11108058 DOI: 10.1017/jfm.2024.297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/24/2024]
Abstract
This paper investigates the transport of drugs delivered by direct injection into the cerebrospinal fluid (CSF) that fills the intrathecal space surrounding the spinal cord. Because of the small drug diffusivity, the dispersion of neutrally buoyant drugs has been shown in previous work to rely mainly on the mean Lagrangian flow associated with the CSF oscillatory motion. Attention is given here to effects of buoyancy, arising when the drug density differs from the CSF density. For the typical density differences found in applications, the associated Richardson number is shown to be of order unity, so that the Lagrangian drift includes a buoyancy-induced component that depends on the spatial distribution of the drug, resulting in a slowly evolving cycle-averaged flow problem that can be analysed with two-time scale methods. The asymptotic analysis leads to a nonlinear integro-differential equation for the spatiotemporal solute evolution that describes accurately drug dispersion at a fraction of the cost involved in direct numerical simulations of the oscillatory flow. The model equation is used to predict drug dispersion of positively and negatively buoyant drugs in an anatomically correct spinal canal, with separate attention given to drug delivery via bolus injection and constant infusion.
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Affiliation(s)
- J. Alaminos-Quesada
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093-0411, USA
| | - C. Gutiérrez-Montes
- Department of Mechanical and Mining Engineering, University of Jaén, Jaén, 23071, Spain
- Andalusian Institute for Earth System Research, University of Jaén, Campus de las Lagunillas, Jaén, 23071, Spain
| | - W. Coenen
- Grupo de Mecánica de Fluidos, Departamento de Ingeniería Térmica y de Fluidos, Universidad Carlos III de Madrid, Leganés, 28911, Spain
| | - A.L. Sánchez
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA, 92093-0411, USA
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Seiner A, Burla GKR, Shrestha D, Bowen M, Horvath JD, Martin BA. Investigation of Human Intrathecal Solute Transport Dynamics Using a Novel in vitro Cerebrospinal Fluid System Analog. FRONTIERS IN NEUROIMAGING 2022; 1:879098. [PMID: 37555174 PMCID: PMC10406265 DOI: 10.3389/fnimg.2022.879098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 05/24/2022] [Indexed: 08/10/2023]
Abstract
BACKGROUND Understanding the relationship between cerebrospinal fluid (CSF) dynamics and intrathecal drug delivery (ITDD) injection parameters is essential to improve treatment of central nervous system (CNS) disorders. METHODS An anatomically detailed in vitro model of the complete CSF system was constructed. Patient-specific cardiac- and respiratory-induced CSF oscillations were input to the model in the subarachnoid space and within the ventricles. CSF production was input at the lateral ventricles and CSF absorption at the superior sagittal sinus. A model small molecule simulated drug product containing fluorescein was imaged within the system over a period of 3-h post-lumbar ITDD injections and used to quantify the impact of (a) bolus injection volume and rate, (b) post-injection flush volume, rate, and timing, (c) injection location, and (d) type of injection device. For each experiment, neuraxial distribution of fluorescein in terms of spatial temporal concentration, area-under-the-curve (AUC), and percent of injected dose (%ID) to the brain was quantified at a time point 3-h post-injection. RESULTS For all experiments conducted with ITDD administration in the lumbar spine, %ID to the brain did not exceed 11.6% at a time point 3-h post-injection. Addition of a 12 mL flush slightly increased solute transport to the brain up to +3.9%ID compared to without a flush (p < 0.01). Implantation of a lumbar catheter with the tip at an equivalent location to the lumbar placed needle, but with rostral tip orientation, resulted in a small improvement of 1.5%ID to the brain (p < 0.05). An increase of bolus volume from 5 to 20 mL improved solute transport to the brain from 5.0 to 6.3%ID, but this improvement was not statistically significant. Increasing bolus injection rate from 5 to 13.3 mL/min lacked improvement of solute transport to the brain, with a value of 6.3 compared to 5.7%ID. CONCLUSION The in vitro modeling approach allowed precisely controlled and repeatable parametric investigation of ITDD injection protocols and devices. In combination, the results predict that parametric changes in lumbar spine ITDD-injection related parameters and devices can alter %ID to the brain and be tuned to optimize therapeutic benefit to CNS targets.
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Affiliation(s)
- Akari Seiner
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States
| | | | - Dev Shrestha
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States
| | - Mayumi Bowen
- Genentech, Inc., A Member of the Roche Group, South San Francisco, CA, United States
| | - Joshua D. Horvath
- Genentech, Inc., A Member of the Roche Group, South San Francisco, CA, United States
| | - Bryn A. Martin
- Department of Chemical and Biological Engineering, University of Idaho, Moscow, ID, United States
- Alcyone Therapeutics Inc., Lowell, MA, United States
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Khani M, Burla GKR, Sass LR, Arters ON, Xing T, Wu H, Martin BA. Human in silico trials for parametric computational fluid dynamics investigation of cerebrospinal fluid drug delivery: impact of injection location, injection protocol, and physiology. Fluids Barriers CNS 2022; 19:8. [PMID: 35090516 PMCID: PMC8796513 DOI: 10.1186/s12987-022-00304-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/03/2022] [Indexed: 11/11/2022] Open
Abstract
Background Intrathecal drug delivery has a significant role in pain management and central nervous system (CNS) disease therapeutics. A fluid-physics based tool to assist clinicians in choosing specific drug doses to the spine or brain may help improve treatment schedules. Methods This study applied computational fluid dynamics (CFD) and in vitro model verification to assess intrathecal drug delivery in an anatomically idealized model of the human CSF system with key anatomic features of the CNS. Key parameters analyzed included the role of (a) injection location including lumbar puncture (LP), cisterna magna (CM) and intracerebroventricular (ICV), (b) LP injection rate, injection volume, and flush volume, (c) physiologic factors including cardiac-induced and deep respiration-induced CSF stroke volume increase. Simulations were conducted for 3-h post-injection and used to quantify spatial–temporal tracer concentration, regional area under the curve (AUC), time to maximum concentration (Tmax), and maximum concentration (Cmax), for each case. Results CM and ICV increased AUC to brain regions by ~ 2 logs compared to all other simulations. A 3X increase in bolus volume and addition of a 5 mL flush both increased intracranial AUC to the brain up to 2X compared to a baseline 5 mL LP injection. In contrast, a 5X increase in bolus rate (25 mL/min) did not improve tracer exposure to the brain. An increase in cardiac and respiratory CSF movement improved tracer spread to the brain, basal cistern, and cerebellum up to ~ 2 logs compared to the baseline LP injection. Conclusion The computational modeling approach provides ability to conduct in silico trials representative of CSF injection protocols. Taken together, the findings indicate a strong potential for delivery protocols to be optimized to reach a target region(s) of the spine and/or brain with a needed therapeutic dose. Parametric modification of bolus rate/volume and flush volume was found to have impact on tracer distribution; albeit to a smaller degree than injection location, with CM and ICV injections resulting in greater therapeutic dose to brain regions compared to LP. CSF stroke volume and frequency both played an important role and may potentially have a greater impact than the modest changes in LP injection protocols analyzed such as bolus rate, volume, and flush. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-022-00304-4.
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Pizzichelli G, Kehlet B, Evju Ø, Martin BA, Rognes ME, Mardal KA, Sinibaldi E. Numerical study of intrathecal drug delivery to a permeable spinal cord: effect of catheter position and angle. Comput Methods Biomech Biomed Engin 2017; 20:1599-1608. [DOI: 10.1080/10255842.2017.1393805] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- G. Pizzichelli
- Istituto Italiano di Tecnologia, Center for Micro-BioRobotics, Pontedera, Italy
| | - B. Kehlet
- Simula Research Laboratory, Lysaker, Norway
| | - Ø. Evju
- Simula Research Laboratory, Lysaker, Norway
| | - B. A. Martin
- Department of Biological Engineering, The University of Idaho, Moscow, ID, USA
| | - M. E. Rognes
- Simula Research Laboratory, Lysaker, Norway
- Departments of Mathematics and Informatics, University of Oslo, Oslo, Norway
| | - K. A. Mardal
- Simula Research Laboratory, Lysaker, Norway
- Departments of Mathematics and Informatics, University of Oslo, Oslo, Norway
| | - E. Sinibaldi
- Istituto Italiano di Tecnologia, Center for Micro-BioRobotics, Pontedera, Italy
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Haga PT, Pizzichelli G, Mortensen M, Kuchta M, Pahlavian SH, Sinibaldi E, Martin BA, Mardal KA. A numerical investigation of intrathecal isobaric drug dispersion within the cervical subarachnoid space. PLoS One 2017; 12:e0173680. [PMID: 28296953 PMCID: PMC5351861 DOI: 10.1371/journal.pone.0173680] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 02/25/2017] [Indexed: 12/19/2022] Open
Abstract
Intrathecal drug and gene vector delivery is a procedure to release a solute within the cerebrospinal fluid. This procedure is currently used in clinical practice and shows promise for treatment of several central nervous system pathologies. However, intrathecal delivery protocols and systems are not yet optimized. The aim of this study was to investigate the effects of injection parameters on solute distribution within the cervical subarachnoid space using a numerical platform. We developed a numerical model based on a patient-specific three dimensional geometry of the cervical subarachnoid space with idealized dorsal and ventral nerve roots and denticulate ligament anatomy. We considered the drug as massless particles within the flow field and with similar properties as the CSF, and we analyzed the effects of anatomy, catheter position, angle and injection flow rate on solute distribution within the cerebrospinal fluid by performing a series of numerical simulations. Results were compared quantitatively in terms of drug peak concentration, spread, accumulation rate and appearance instant over 15 seconds following the injection. Results indicated that solute distribution within the cervical spine was altered by all parameters investigated within the time range analyzed following the injection. The presence of spinal cord nerve roots and denticulate ligaments increased drug spread by 60% compared to simulations without these anatomical features. Catheter position and angle were both found to alter spread rate up to 86%, and catheter flow rate altered drug peak concentration up to 78%. The presented numerical platform fills a first gap towards the realization of a tool to parametrically assess and optimize intrathecal drug and gene vector delivery protocols and systems. Further investigation is needed to analyze drug spread over a longer clinically relevant time frame.
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Affiliation(s)
- Per Thomas Haga
- Center for Biomedical Computing, Simula Research Laboratory, Fornebu, Norway
| | - Giulia Pizzichelli
- Istituto Italiano di Tecnologia, Center for Micro-BioRobotics, Pontedera, Italy
- Scuola Superiore Sant’Anna, The BioRobotics Institute, Pontedera, Italy
| | - Mikael Mortensen
- Center for Biomedical Computing, Simula Research Laboratory, Fornebu, Norway
- Dept. of Mathematics, University of Oslo, Oslo, Norway
| | | | - Soroush Heidari Pahlavian
- Conquer Chiari Research Center, Dept. of Mech. Engineering, University of Akron, Akron, Ohio, United States of America
| | - Edoardo Sinibaldi
- Istituto Italiano di Tecnologia, Center for Micro-BioRobotics, Pontedera, Italy
| | - Bryn A. Martin
- Dept. of Biological Engineering, The University of Idaho, Moscow, Idaho, United States of America
- * E-mail:
| | - Kent-Andre Mardal
- Center for Biomedical Computing, Simula Research Laboratory, Fornebu, Norway
- Dept. of Mathematics, University of Oslo, Oslo, Norway
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Golberg A. ANALYTICAL MODEL OF LOCAL DISTRIBUTION OF CHEMICALS IN TISSUES WITH FIRST-ORDER-RATE METABOLISM KINETICS. CHEM ENG COMMUN 2014. [DOI: 10.1080/00986445.2012.762628] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Stockman HW. Effect of anatomical fine structure on the dispersion of solutes in the spinal subarachnoid space. J Biomech Eng 2007; 129:666-75. [PMID: 17887892 DOI: 10.1115/1.2768112] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The dispersion of a solute bolus is calculated for cerebrospinal fluid undergoing oscillatory flow in the subarachnoid space of the spine. The fine structure of the subarachnoid space (nerves and trabeculae) enhances both longitudinal and transverse dispersions five to ten times over a simple model with an open annular space. Overall, dispersion is >10(3) times simple molecular diffusion. The result of enhanced dispersion is rapid spread and dilution of the bolus, effectively stirred by fluid movement around the fine structure.
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Affiliation(s)
- Harlan W Stockman
- Sandia National Laboratories, Department 6118, Albuquerque, New Mexico 87185-0750, USA
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Loth F, Yardimci MA, Alperin N. Hydrodynamic modeling of cerebrospinal fluid motion within the spinal cavity. J Biomech Eng 2001; 123:71-9. [PMID: 11277305 DOI: 10.1115/1.1336144] [Citation(s) in RCA: 170] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The fluid that resides within cranial and spinal cavities, cerebrospinal fluid (CSF), moves in a pulsatile fashion to and from the cranial cavity. This motion can be measured hy magnetic resonance imaging (MRI) and may he of clinical importance in the diagnosis of several brain and spinal cord disorders such as hydrocephalus, Chiari malformation, and syringomyelia. In the present work, a geometric and hydrodynamic characterization of an anatomically relevant spinal canal model is presented. We found that inertial effects dominate the flow field under normal physiological flow rates. Along the length of the spinal canal, hydraulic diameter was found to vary significantly from 5 to 15 mm. The instantaneous Reynolds number at peak flow rate ranged from 150 to 450, and the Womersle number ranged from 5 to 17. Pulsatile flow calculations are presented for an idealized geometric representation of the spinal cavity. A linearized Navier-Stokes model of the pulsatile CSF flow was constructed based on MRI flow rate measurements taken on a healthy volunteer. The numerical model was employed to investigate effects of cross-sectional geometry and spinal cord motion on unsteady velocity, shear stress, and pressure gradientfields. The velocity field was shown to be blunt, due to the inertial character of the flow, with velocity peaks located near the boundaries of the spinal canal rather than at the midpoint between boundaries. The pressure gradient waveform was found to be almost exclusively dependent on the flow waveform and cross-sectional area. Characterization of the CSF dynamics in normal and diseased states may be important in understanding the pathophysiology of CSF related disorders. Flow models coupled with MRI flow measurements mnay become a noninvasive tool to explain the abnormal dynamics of CSF in related brain disorders as well as to determine concentration and local distribution of drugs delivered into the CSF space.
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Affiliation(s)
- F Loth
- Department of Mechanical Engineering, University of Illinois at Chicago, 60607, USA
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Anderson L, Walker J, Brydon C, Serpell MG. Rate of injection through whitacre needles affects distribution of spinal anaesthesia. Br J Anaesth 2001; 86:245-8. [PMID: 11573668 DOI: 10.1093/bja/86.2.245] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A prospective, randomized, double-blind study was performed to investigate whether altering the rate of injection of local anaesthetic through a Whitacre needle had any effect on the spinal block achieved. Twenty patients scheduled for elective urological surgery under spinal anaesthesia received an injection of 3 ml of 0.5% plain bupivacaine either by hand (fast) over 10 s (18 ml min(-1)) or by infusion pump (slow) over 3 min (1 ml min(-1)). All patients were in the sitting position both during insertion of the spinal needle and for 3 min after the start of spinal injection, and they then changed to the supine position. The slow injection group achieved peak sensory block earlier, after a median interval of 20 (95% confidence interval 12.5-30) min vs 30 (22.5-45) min (P<0.05) for the fast group. The level of peak sensory block was similar: T3.5 (T2-T4.5) vs T4 (T1.5-T6.5). The time to lowest mean arterial pressure occurred earlier in the slow group, at 10 (8 to 18) vs 20 (15-31) min (P<0.05). Duration of the motor block was shorter in the slow group: 180 (152-242) vs 270 (225-300). We conclude that a slow spinal injection of plain bupivacaine results in a block of more rapid onset and recovery.
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Affiliation(s)
- L Anderson
- Department of Anaesthesia, Western Infirmary, Glasgow, UK
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Myers MR, Malinauskas RA. Effect of orifice-area reduction on flow characteristics during injection through spinal needles. Anaesthesia 1998; 53:151-6. [PMID: 9534638 DOI: 10.1046/j.1365-2044.1998.00286.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A reduction in hole size for certain side-port spinal needles has been advocated in recent reports. While the influence of orifice-area reduction on the aspiration capability of the needle has been studied, the influence on the anaesthetic delivery properties is relatively unknown. As a first step in understanding the effects of hole-size reduction on anaesthetic distribution within the subarachnoid space, we studied flows emanating from isolated needles using computer simulations. Following validation of the numerical model using experimental particle visualisation, trajectories of anaesthetic particles injected through 25 G Whitacre needles of various orifice areas were computed and used to determine the orientation and rate of spread of the anaesthetic jet exiting the needle. Two factors impacting the concentration distribution were observed: the rate of spread of the anaesthetic jet increases markedly with decreasing orifice area and the jet alignment shifts toward perpendicular to the needle axis.
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Affiliation(s)
- M R Myers
- Center for Devices and Radiological Health, US Food and Drug Administration, Rockville, MD 20852, USA
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