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Morand J, McClellan P, Isali I, Dikici Y, Fan D, Li L, Shoffstall AJ, Akkus O, Weidenbecher M. Dexamethasone eluting polydopaminated polycaprolactone-poly (lactic-co-glycolic) acid for treatment of tracheal stenosis. J Biomed Mater Res A 2024; 112:781-792. [PMID: 38204293 DOI: 10.1002/jbm.a.37659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 12/06/2023] [Accepted: 12/08/2023] [Indexed: 01/12/2024]
Abstract
Tracheal stenosis is commonly caused by injury, resulting in inflammation and fibrosis. Inhibiting inflammation and promoting epithelization can reduce recurrence after initial successful treatment of tracheal stenosis. Steroids play an important role in tracheal stenosis management. This study in vitro evaluated effectiveness of a polydopaminated polycaprolactone stent coated with dexamethasone-eluting poly(lactic-co-glycolic) acid microparticles (μPLGA) for tracheal stenosis management. Polydopamination was characterized by Raman spectroscopy and promoted epithelialization while dexamethasone delivery reduced macrophage activity, assessed by individual cell area measurements and immunofluorescent staining for inducible nitric oxide synthase (iNOS). Dexamethasone release was quantified by high-performance liquid chromatography over 30 days. Activation-related increase in cell area and iNOS production by RAW 264.7 were both reduced significantly (p < .05) through dexamethasone release. Epithelial cell spreading was higher on polydopaminated polycaprolactone (PCL) than PCL-alone (p < .05). Force required for stent migration was measured by pullout tests of PCL-μPLGA stents from cadaveric rabbit and porcine tracheas (0.425 ± 0.068 N and 1.082 ± 0.064 N, respectively) were above forces estimated to occur during forced respiration. Biomechanical support provided by stents to prevent airway collapse was assessed by comparing compressive circumferential stiffness, and stiffness of the stent was about 1/10th of the rabbit trachea (0.156 ± 0.023 N/mm vs. 1.420 ± 0.194 N/mm, respectively). A dexamethasone-loaded PCL-μPLGA stent platform can deliver dexamethasone and exhibits sufficient mechanical properties to anchor within the trachea and polydopamination of PCL is conducive to epithelial layer formation. Therefore, a polydopaminated PCL-μPLGA stent is a promising candidate for in vivo evaluation for treatment of tracheal restenosis.
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Affiliation(s)
- Jacob Morand
- Advanced Platform Center, Louis Stokes Cleveland Veteran Affairs Medical Center, Cleveland, Ohio, USA
| | - Phillip McClellan
- Department of Urology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ilaha Isali
- Department of Urology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yusuf Dikici
- Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Di Fan
- Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Longshun Li
- Advanced Platform Center, Louis Stokes Cleveland Veteran Affairs Medical Center, Cleveland, Ohio, USA
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Andrew J Shoffstall
- Advanced Platform Center, Louis Stokes Cleveland Veteran Affairs Medical Center, Cleveland, Ohio, USA
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Ozan Akkus
- Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, USA
- Department of Orthopedic Surgery, University Hospitals Cleveland Medical Center, Cleveland, Ohio, USA
| | - Mark Weidenbecher
- Advanced Platform Center, Louis Stokes Cleveland Veteran Affairs Medical Center, Cleveland, Ohio, USA
- Department of Otolaryngology, Case Western Reserve University, Cleveland, Ohio, USA
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2
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Bhowmick S, Graham RD, Verma N, Trevathan JK, Franke M, Nieuwoudt S, Fisher LE, Shoffstall AJ, Weber DJ, Ludwig KA, Lempka SF. Computational modeling of dorsal root ganglion stimulation using an Injectrode. J Neural Eng 2024; 21:026039. [PMID: 38502956 PMCID: PMC11007586 DOI: 10.1088/1741-2552/ad357f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 02/23/2024] [Accepted: 03/19/2024] [Indexed: 03/21/2024]
Abstract
Objective.Minimally invasive neuromodulation therapies like the Injectrode, which is composed of a tightly wound polymer-coated Platinum/Iridium microcoil, offer a low-risk approach for administering electrical stimulation to the dorsal root ganglion (DRG). This flexible electrode is aimed to conform to the DRG. The stimulation occurs through a transcutaneous electrical stimulation (TES) patch, which subsequently transmits the stimulation to the Injectrode via a subcutaneous metal collector. However, it is important to note that the effectiveness of stimulation through TES relies on the specific geometrical configurations of the Injectrode-collector-patch system. Hence, there is a need to investigate which design parameters influence the activation of targeted neural structures.Approach.We employed a hybrid computational modeling approach to analyze the impact of Injectrode system design parameters on charge delivery and neural response to stimulation. We constructed multiple finite element method models of DRG stimulation, followed by the implementation of multi-compartment models of DRG neurons. By calculating potential distribution during monopolar stimulation, we simulated neural responses using various parameters based on prior acute experiments. Additionally, we developed a canonical monopolar stimulation and full-scale model of bipolar bilateral L5 DRG stimulation, allowing us to investigate how design parameters like Injectrode size and orientation influenced neural activation thresholds.Main results.Our findings were in accordance with acute experimental measurements and indicate that the minimally invasive Injectrode system predominantly engages large-diameter afferents (Aβ-fibers). These activation thresholds were contingent upon the surface area of the Injectrode. As the charge density decreased due to increasing surface area, there was a corresponding expansion in the stimulation amplitude range before triggering any pain-related mechanoreceptor (Aδ-fibers) activity.Significance.The Injectrode demonstrates potential as a viable technology for minimally invasive stimulation of the DRG. Our findings indicate that utilizing a larger surface area Injectrode enhances the therapeutic margin, effectively distinguishing the desired Aβactivation from the undesired Aδ-fiber activation.
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Affiliation(s)
- Sauradeep Bhowmick
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Robert D Graham
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
| | - Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States of America
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States of America
| | | | | | - Lee E Fisher
- Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Andrew J Shoffstall
- Neuronoff Inc., Cleveland, OH, United States of America
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Douglas J Weber
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States of America
- Neuroscience Institute, Carnegie Mellon University, Pittsburgh, PA, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin–Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe)–Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin–Madison, Madison, WI, United States of America
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
- Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States of America
- Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States of America
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Lam DV, Lindemann M, Yang K, Liu DX, Ludwig KA, Shoffstall AJ. An Open-Source 3D-Printed Hindlimb Stabilization Apparatus for Reliable Measurement of Stimulation-Evoked Ankle Flexion in Rat. eNeuro 2024; 11:ENEURO.0305-23.2023. [PMID: 38164555 PMCID: PMC10918511 DOI: 10.1523/eneuro.0305-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 11/09/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024] Open
Abstract
Currently there are numerous methods to evaluate peripheral nerve stimulation interfaces in rats, with stimulation-evoked ankle torque being one of the most prominent. Commercial rat ankle torque measurement systems and custom one-off solutions have been published in the literature. However, commercial systems are proprietary and costly and do not allow for customization. One-off lab-built systems have required specialized machining expertise, and building plans have previously not been made easily accessible. Here, detailed building plans are provided for a low-cost, open-source, and basic ankle torque measurement system from which additional customization can be made. A hindlimb stabilization apparatus was developed to secure and stabilize a rat's hindlimb, while allowing for simultaneous ankle-isometric torque and lower limb muscle electromyography (EMG). The design was composed mainly of adjustable 3D-printed components to accommodate anatomical differences between rat hindlimbs. Additionally, construction and calibration procedures of the rat hindlimb stabilization apparatus were demonstrated in this study. In vivo torque measurements were reliably acquired and corresponded to increasing stimulation amplitudes. Furthermore, implanted leads used for intramuscular EMG recordings complemented torque measurements and were used as an additional functional measurement in evaluating the performance of a peripheral nerve stimulation interface. In conclusion, an open-source and noninvasive platform, made primarily with 3D-printed components, was constructed for reliable data acquisition of evoked motor activity in rat models. The purpose of this apparatus is to provide researchers a versatile system with adjustable components that can be tailored to meet user-defined experimental requirements when evaluating motor function of the rat hindlimbs.
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Affiliation(s)
- Danny V Lam
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland 44106, Ohio
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland 44106, Ohio
| | - Madeline Lindemann
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland 44106, Ohio
| | - Kevin Yang
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland 44106, Ohio
| | - Derrick X Liu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland 44106, Ohio
| | - Kip A Ludwig
- Department of Neurosurgery, University of Wisconsin-Madison, Madison 53705, Wisconsin
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland 44106, Ohio
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland 44106, Ohio
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4
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Bhowmick S, Graham RD, Verma N, Trevathan JK, Franke M, Nieuwoudt S, Fisher LE, Shoffstall AJ, Weber DJ, Ludwig KA, Lempka SF. Computational modeling of dorsal root ganglion stimulation using an Injectrode. bioRxiv 2023:2023.09.20.558675. [PMID: 37790562 PMCID: PMC10542492 DOI: 10.1101/2023.09.20.558675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Objective Minimally invasive neuromodulation therapies like the Injectrode, which is composed of a tightly wound polymer-coated platinum/iridium microcoil, offer a low-risk approach for administering electrical stimulation to the dorsal root ganglion (DRG). This flexible electrode is aimed to conform to the DRG. The stimulation occurs through a transcutaneous electrical stimulation (TES) patch, which subsequently transmits the stimulation to the Injectrode via a subcutaneous metal collector. However, effectiveness of stimulation relies on the specific geometrical configurations of the Injectrode-collector-patch system. Hence, there is a need to investigate which design parameters influence the activation of targeted neural structures. Approach We employed a hybrid computational modeling approach to analyze the impact of the Injectrode system design parameters on charge delivery and the neural response to stimulation. We constructed multiple finite element method models of DRG stimulation and multi-compartment models of DRG neurons. We simulated the neural responses using parameters based on prior acute preclinical experiments. Additionally, we developed multiple human-scale computational models of DRG stimulation to investigate how design parameters like Injectrode size and orientation influenced neural activation thresholds. Main results Our findings were in accordance with acute experimental measurements and indicated that the Injectrode system predominantly engages large-diameter afferents (Aβ-fibers). These activation thresholds were contingent upon the surface area of the Injectrode. As the charge density decreased due to increasing surface area, there was a corresponding expansion in the stimulation amplitude range before triggering any pain-related mechanoreceptor (Aδ-fibers) activity. Significance The Injectrode demonstrates potential as a viable technology for minimally invasive stimulation of the DRG. Our findings indicate that utilizing a larger surface area Injectrode enhances the therapeutic margin, effectively distinguishing the desired Aβ activation from the undesired Aδ-fiber activation.
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Lam DV, Javadekar A, Patil N, Yu M, Li L, Menendez DM, Gupta AS, Capadona JR, Shoffstall AJ. Platelets and hemostatic proteins are co-localized with chronic neuroinflammation surrounding implanted intracortical microelectrodes. Acta Biomater 2023; 166:278-290. [PMID: 37211307 PMCID: PMC10330779 DOI: 10.1016/j.actbio.2023.05.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 04/13/2023] [Accepted: 05/02/2023] [Indexed: 05/23/2023]
Abstract
Intracortical microelectrodes induce vascular injury upon insertion into the cortex. As blood vessels rupture, blood proteins and blood-derived cells (including platelets) are introduced into the 'immune privileged' brain tissues at higher-than-normal levels, passing through the damaged blood-brain barrier. Blood proteins adhere to implant surfaces, increasing the likelihood of cellular recognition leading to activation of immune and inflammatory cells. Persistent neuroinflammation is a major contributing factor to declining microelectrode recording performance. We investigated the spatial and temporal relationship of blood proteins fibrinogen and von Willebrand Factor (vWF), platelets, and type IV collagen, in relation to glial scarring markers for microglia and astrocytes following implantation of non-functional multi-shank silicon microelectrode probes into rats. Together with type IV collagen, fibrinogen and vWF augment platelet recruitment, activation, and aggregation. Our main results indicate blood proteins participating in hemostasis (fibrinogen and vWF) persisted at the microelectrode interface for up to 8-weeks after implantation. Further, type IV collagen and platelets surrounded the probe interface with similar spatial and temporal trends as vWF and fibrinogen. In addition to prolonged blood-brain barrier instability, specific blood and extracellular matrix proteins may play a role in promoting the inflammatory activation of platelets and recruitment to the microelectrode interface. STATEMENT OF SIGNIFICANCE: Implanted microelectrodes have substantial potential for restoring function to people with paralysis and amputation by providing signals that feed into natural control algorithms that drive prosthetic devices. Unfortunately, these microelectrodes do not display robust performance over time. Persistent neuroinflammation is widely thought to be a primary contributor to the devices' progressive decline in performance. Our manuscript reports on the highly local and persistent accumulation of platelets and hemostatic blood proteins around the microelectrode interface of brain implants. To our knowledge neuroinflammation driven by cellular and non-cellular responses associated with hemostasis and coagulation has not been rigorously quantified elsewhere. Our findings identify potential targets for therapeutic intervention and a better understanding of the driving mechanisms to neuroinflammation in the brain.
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Affiliation(s)
- Danny V Lam
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Anisha Javadekar
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | | | - Marina Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Longshun Li
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Dhariyat M Menendez
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Anirban Sen Gupta
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA; Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA.
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Buyukcelik ON, Lapierre-Landry M, Kolluru C, Upadhye AR, Marshall DP, Pelot NA, Ludwig KA, Gustafson KJ, Wilson DL, Jenkins MW, Shoffstall AJ. Deep-learning segmentation of fascicles from microCT of the human vagus nerve. Front Neurosci 2023; 17:1169187. [PMID: 37332862 PMCID: PMC10275336 DOI: 10.3389/fnins.2023.1169187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 04/12/2023] [Indexed: 06/20/2023] Open
Abstract
Introduction MicroCT of the three-dimensional fascicular organization of the human vagus nerve provides essential data to inform basic anatomy as well as the development and optimization of neuromodulation therapies. To process the images into usable formats for subsequent analysis and computational modeling, the fascicles must be segmented. Prior segmentations were completed manually due to the complex nature of the images, including variable contrast between tissue types and staining artifacts. Methods Here, we developed a U-Net convolutional neural network (CNN) to automate segmentation of fascicles in microCT of human vagus nerve. Results The U-Net segmentation of ~500 images spanning one cervical vagus nerve was completed in 24 s, versus ~40 h for manual segmentation, i.e., nearly four orders of magnitude faster. The automated segmentations had a Dice coefficient of 0.87, a measure of pixel-wise accuracy, thus suggesting a rapid and accurate segmentation. While Dice coefficients are a commonly used metric to assess segmentation performance, we also adapted a metric to assess fascicle-wise detection accuracy, which showed that our network accurately detects the majority of fascicles, but may under-detect smaller fascicles. Discussion This network and the associated performance metrics set a benchmark, using a standard U-Net CNN, for the application of deep-learning algorithms to segment fascicles from microCT images. The process may be further optimized by refining tissue staining methods, modifying network architecture, and expanding the ground-truth training data. The resulting three-dimensional segmentations of the human vagus nerve will provide unprecedented accuracy to define nerve morphology in computational models for the analysis and design of neuromodulation therapies.
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Affiliation(s)
- Ozge N. Buyukcelik
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technologies Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Maryse Lapierre-Landry
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Chaitanya Kolluru
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Aniruddha R. Upadhye
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technologies Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Daniel P. Marshall
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Nicole A. Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin Madison, Madison, WI, United States
- Department of Neurological Surgery, University of Wisconsin Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering, Madison, WI, United States
| | - Kenneth J. Gustafson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Functional Electrical Stimulation Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - David L. Wilson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Michael W. Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Department of Pediatrics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technologies Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
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Blanz SL, Musselman ED, Settell ML, Knudsen BE, Nicolai EN, Trevathan JK, Verner RS, Begnaud J, Skubal AC, Suminski AJ, Williams JC, Shoffstall AJ, Grill WM, Pelot NA, Ludwig KA. Spatially selective stimulation of the pig vagus nerve to modulate target effect versus side effect. J Neural Eng 2023; 20:10.1088/1741-2552/acb3fd. [PMID: 36649655 PMCID: PMC10339030 DOI: 10.1088/1741-2552/acb3fd] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/17/2023] [Indexed: 01/18/2023]
Abstract
Electrical stimulation of the cervical vagus nerve using implanted electrodes (VNS) is FDA-approved for the treatment of drug-resistant epilepsy, treatment-resistant depression, and most recently, chronic ischemic stroke rehabilitation. However, VNS is critically limited by the unwanted stimulation of nearby neck muscles-a result of non-specific stimulation activating motor nerve fibers within the vagus. Prior studies suggested that precise placement of small epineural electrodes can modify VNS therapeutic effects, such as cardiac responses. However, it remains unclear if placement can alter the balance between intended effect and limiting side effect. We used an FDA investigational device exemption approved six-contact epineural cuff to deliver VNS in pigs and quantified how epineural electrode location impacts on- and off-target VNS activation. Detailed post-mortem histology was conducted to understand how the underlying neuroanatomy impacts observed functional responses. Here we report the discovery and characterization of clear neuroanatomy-dependent differences in threshold and saturation for responses related to both effect (change in heart rate) and side effect (neck muscle contractions). The histological and electrophysiological data were used to develop and validate subject-specific computation models of VNS, creating a well-grounded quantitative framework to optimize electrode location-specific activation of nerve fibers governing intended effect versus unwanted side effect.
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Affiliation(s)
- Stephan L Blanz
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
| | - Eric D Musselman
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Megan L Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Bruce E Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Evan N Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
- Mayo Clinic, Rochester, MN, United States of America
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Ryan S Verner
- LivaNova USA Inc., Houston, TX, United States of America
| | - Jason Begnaud
- LivaNova USA Inc., Houston, TX, United States of America
| | - Aaron C Skubal
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Aaron J Suminski
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Warren M Grill
- University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States of America
- Department of Neurobiology, Duke University, Durham, NC, United States of America
- Department of Neurosurgery, Duke University, Durham, NC, United States of America
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
- Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
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8
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Verma N, Le T, Mudge J, Nicksic PJ, Xistris L, Kasole M, Shoffstall AJ, Poore SO, Ludwig KA, Dingle AM. Efficacy of bone stimulators in large-animal models and humans may be limited by weak electric fields reaching fracture. Sci Rep 2022; 12:21798. [PMID: 36526728 PMCID: PMC9758190 DOI: 10.1038/s41598-022-26215-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Noninvasive electronic bone growth stimulators (EBGSs) have been in clinical use for decades. However, systematic reviews show inconsistent and limited clinical efficacy. Further, noninvasive EBGS studies in small animals, where the stimulation electrode is closer to the fracture site, have shown promising efficacy, which has not translated to large animals or humans. We propose that this is due to the weaker electric fields reaching the fracture site when scaling from small animals to large animals and humans. To address this gap, we measured the electric field strength reaching the bone during noninvasive EBGS therapy in human and sheep cadaver legs and in finite element method (FEM) models of human and sheep legs. During application of 1100 V/m with an external EBGS, only 21 V/m reached the fracture site in humans. Substantially weaker electric fields reached the fracture site during the later stages of healing and at increased bone depths. To augment the electric field strength reaching the fracture site during noninvasive EBGS therapy, we introduced the Injectrode, an injectable electrode that spans the distance between the bone and subcutaneous tissue. Our study lays the groundwork to improve the efficacy of noninvasive EBGSs by increasing the electric field strength reaching the fracture site.
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Affiliation(s)
- Nishant Verma
- grid.14003.360000 0001 2167 3675Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI USA
| | - Todd Le
- grid.14003.360000 0001 2167 3675Division of Plastic Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI USA
| | - Jonah Mudge
- grid.14003.360000 0001 2167 3675Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI USA
| | - Peter J. Nicksic
- grid.14003.360000 0001 2167 3675Division of Plastic Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI USA
| | - Lillian Xistris
- grid.14003.360000 0001 2167 3675Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Division of Plastic Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI USA
| | - Maisha Kasole
- grid.14003.360000 0001 2167 3675Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI USA
| | - Andrew J. Shoffstall
- grid.67105.350000 0001 2164 3847Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH USA ,grid.410349.b0000 0004 5912 6484Advanced Platform Technology Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH USA
| | - Samuel O. Poore
- grid.14003.360000 0001 2167 3675Division of Plastic Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI USA
| | - Kip A. Ludwig
- grid.14003.360000 0001 2167 3675Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI USA ,grid.14003.360000 0001 2167 3675Department of Neurological Surgery, University of Wisconsin-Madison, Madison, WI USA
| | - Aaron M. Dingle
- grid.14003.360000 0001 2167 3675Division of Plastic Surgery, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI USA
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9
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Hoeferlin GF, Menendez DM, Krebs OK, Capadona JR, Shoffstall AJ. Assessment of Thermal Damage from Robot-Drilled Craniotomy for Cranial Window Surgery in Mice. J Vis Exp 2022. [DOI: 10.3791/64188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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10
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Upadhye AR, Kolluru C, Druschel L, Lababidi LA, Ahmad SS, Menendez DM, Buyukcelik ON, Settell ML, Blanz SL, Jenkins MW, Wilson DL, Zhang J, Tatsuoka C, Grill WM, Pelot NA, Ludwig KA, Gustafson KJ, Shoffstall AJ. Fascicles split or merge every ∼560 microns within the human cervical vagus nerve. J Neural Eng 2022; 19:10.1088/1741-2552/ac9643. [PMID: 36174538 PMCID: PMC10353574 DOI: 10.1088/1741-2552/ac9643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 09/29/2022] [Indexed: 12/24/2022]
Abstract
Objective.Vagus nerve stimulation (VNS) is Food and Drug Administration-approved for epilepsy, depression, and obesity, and stroke rehabilitation; however, the morphological anatomy of the vagus nerve targeted by stimulatation is poorly understood. Here, we used microCT to quantify the fascicular structure and neuroanatomy of human cervical vagus nerves (cVNs).Approach.We collected eight mid-cVN specimens from five fixed cadavers (three left nerves, five right nerves). Analysis focused on the 'surgical window': 5 cm of length, centered around the VNS implant location. Tissue was stained with osmium tetroxide, embedded in paraffin, and imaged on a microCT scanner. We visualized and quantified the merging and splitting of fascicles, and report a morphometric analysis of fascicles: count, diameter, and area.Main results.In our sample of human cVNs, a fascicle split or merge event was observed every ∼560µm (17.8 ± 6.1 events cm-1). Mean morphological outcomes included: fascicle count (6.6 ± 2.8 fascicles; range 1-15), fascicle diameter (514 ± 142µm; range 147-1360µm), and total cross-sectional fascicular area (1.32 ± 0.41 mm2; range 0.58-2.27 mm).Significance.The high degree of fascicular splitting and merging, along with wide range in key fascicular morphological parameters across humans may help to explain the clinical heterogeneity in patient responses to VNS. These data will enable modeling and experimental efforts to determine the clinical effect size of such variation. These data will also enable efforts to design improved VNS electrodes.
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Affiliation(s)
- Aniruddha R. Upadhye
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Chaitanya Kolluru
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Lindsey Druschel
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Luna Al Lababidi
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Sami S. Ahmad
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Dhariyat M. Menendez
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Ozge N. Buyukcelik
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Megan L. Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Stephan L. Blanz
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, USA
| | - Michael W. Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - David L. Wilson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Jing Zhang
- Department of Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, United States of America
| | - Curtis Tatsuoka
- Department of Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, United States of America
- FES Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States of America
- Department of Neurobiology, Duke University, Durham, NC, United States of America
- Department of Neurosurgery, Duke University, Durham, NC, United States of America
| | - Nicole A. Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, USA
| | - Kenneth J. Gustafson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- FES Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
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11
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Liu DX, Lam DV, Gao Y, LeBlanc RC, Usab AA, Fielding ES, Brunkalla CL, Yang K, Shoffstall AJ. Characterization of a Temporary Peripheral Nerve Stimulation Electrode Utilizing a Bioabsorbable Suture Substrate. Annu Int Conf IEEE Eng Med Biol Soc 2022; 2022:5094-5098. [PMID: 36086486 PMCID: PMC10369404 DOI: 10.1109/embc48229.2022.9871604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Electrical stimulation after peripheral nerve injury (PNI) has the potential to promote more rapid and complete recovery of damaged fiber tracts. While permanently implanted devices are commonly used to treat chronic or persistent conditions, they are not ideal solutions for transient medical therapies due to high costs, increased risk of surgical injury, irritation, infection, and persistent inflammation at the site of the implant. Furthermore, removal of temporary leads placed on or around peripheral nerves may have unacceptable risk for nerve injury, which is counterproductive in developing therapies for PNI treatment. Transient devices which provide effective clinical stimulation while being capable of harmless bioabsorption may overcome key challenges in these areas. However, current bioabsorbable devices are limited in their robustness and require complex fabrication strategies and novel materials which may complicate their clinical translation pathway. In this study, we present a simple bioabsorbable / biodegradable electrode fabricated by modifying standard absorbable sutures, and we present data characterizing our prototype's stability in vitro and in vivo.
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12
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Kolluru C, Todd A, Upadhye AR, Liu Y, Berezin MY, Fereidouni F, Levenson RM, Wang Y, Shoffstall AJ, Jenkins MW, Wilson DL. Imaging peripheral nerve micro-anatomy with MUSE, 2D and 3D approaches. Sci Rep 2022; 12:10205. [PMID: 35715554 PMCID: PMC9205958 DOI: 10.1038/s41598-022-14166-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/02/2022] [Indexed: 01/25/2023] Open
Abstract
Understanding peripheral nerve micro-anatomy can assist in the development of safe and effective neuromodulation devices. However, current approaches for imaging nerve morphology at the fiber level are either cumbersome, require substantial instrumentation, have a limited volume of view, or are limited in resolution/contrast. We present alternative methods based on MUSE (Microscopy with Ultraviolet Surface Excitation) imaging to investigate peripheral nerve morphology, both in 2D and 3D. For 2D imaging, fixed samples are imaged on a conventional MUSE system either label free (via auto-fluorescence) or after staining with fluorescent dyes. This method provides a simple and rapid technique to visualize myelinated nerve fibers at specific locations along the length of the nerve and perform measurements of fiber morphology (e.g., axon diameter and g-ratio). For 3D imaging, a whole-mount staining and MUSE block-face imaging method is developed that can be used to characterize peripheral nerve micro-anatomy and improve the accuracy of computational models in neuromodulation. Images of rat sciatic and human cadaver tibial nerves are presented, illustrating the applicability of the method in different preclinical models.
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Affiliation(s)
- Chaitanya Kolluru
- grid.67105.350000 0001 2164 3847Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Austin Todd
- grid.267309.90000 0001 0629 5880University of Texas Health Science Center at San Antonio, San Antonio, TX 78229 USA
| | - Aniruddha R. Upadhye
- grid.67105.350000 0001 2164 3847Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 USA ,grid.410349.b0000 0004 5912 6484APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106 USA
| | - Yehe Liu
- grid.67105.350000 0001 2164 3847Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Mikhail Y. Berezin
- grid.4367.60000 0001 2355 7002Department of Radiology, Washington University in St. Louis, St. Louis, MO 63110 USA
| | - Farzad Fereidouni
- grid.416958.70000 0004 0413 7653Department of Pathology and Laboratory Medicine, UC Davis Health, Sacramento, CA 95817 USA
| | - Richard M. Levenson
- grid.416958.70000 0004 0413 7653Department of Pathology and Laboratory Medicine, UC Davis Health, Sacramento, CA 95817 USA
| | - Yanming Wang
- grid.67105.350000 0001 2164 3847Department of Radiology, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Andrew J. Shoffstall
- grid.67105.350000 0001 2164 3847Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 USA ,grid.410349.b0000 0004 5912 6484APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106 USA
| | - Michael W. Jenkins
- grid.67105.350000 0001 2164 3847Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 USA ,grid.67105.350000 0001 2164 3847Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44106 USA
| | - David L. Wilson
- grid.67105.350000 0001 2164 3847Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 USA ,grid.67105.350000 0001 2164 3847Department of Radiology, Case Western Reserve University, Cleveland, OH 44106 USA
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13
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Krebs OK, Mittal G, Ramani S, Zhang J, Shoffstall AJ, Cogan SF, Pancrazio JJ, Capadona JR. Tools for Surface Treatment of Silicon Planar Intracortical Microelectrodes. J Vis Exp 2022. [PMID: 35758655 DOI: 10.3791/63500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Intracortical microelectrodes hold great therapeutic potential. But they are challenged with significant performance reduction after modest implantation durations. A substantial contributor to the observed decline is the damage to the neural tissue proximal to the implant and subsequent neuroinflammatory response. Efforts to improve device longevity include chemical modifications or coating applications to the device surface to improve the tissue response. Development of such surface treatments is typically completed using non-functional "dummy" probes that lack the electrical components required for the intended application. Translation to functional devices requires additional consideration given the fragility of intracortical microelectrode arrays. Handling tools greatly facilitate surface treatments to assembled devices, particularly for modifications that require long procedural times. The handling tools described here are used for surface treatments applied via gas-phase deposition and aqueous solution exposure. Characterization of the coating is performed using ellipsometry and x-ray photoelectron spectroscopy. A comparison of electrical impedance spectroscopy recordings before and after the coating procedure on functional devices confirmed device integrity following modification. The described tools can be readily adapted for alternative electrode devices and treatment methods that maintain chemical compatibility.
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Affiliation(s)
- Olivia K Krebs
- Department of Biomedical Engineering, Case Western Reserve University; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center
| | - Gaurav Mittal
- Department of Biomedical Engineering, Case Western Reserve University; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center
| | - Shreya Ramani
- Department of Biomedical Engineering, Case Western Reserve University; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center
| | - Jichu Zhang
- Department of Biomedical Engineering, Case Western Reserve University; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center
| | - Stuart F Cogan
- Department of Bioengineering, The University of Texas at Dallas
| | | | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University; Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center;
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14
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Nicksic PJ, Donnelly DT, Verma N, Setiz AJ, Shoffstall AJ, Ludwig KA, Dingle AM, Poore SO. Electrical Stimulation of Acute Fractures: A Narrative Review of Stimulation Protocols and Device Specifications. Front Bioeng Biotechnol 2022; 10:879187. [PMID: 35721861 PMCID: PMC9201474 DOI: 10.3389/fbioe.2022.879187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
Orthopedic fractures have a significant impact on patients in the form of economic loss and functional impairment. Beyond the standard methods of reduction and fixation, one adjunct that has been explored since the late 1970s is electrical stimulation. Despite robust evidence for efficacy in the preclinical arena, human trials have mixed results, and this technology is not widely accepted. The purpose of this review is to examine the body of literature supporting electrical stimulation for the purpose of fracture healing in humans with an emphasis on device specifications and stimulation protocols and delineate a minimum reporting checklist for future studies of this type. We have isolated 12 studies that pertain to the administration of electrical stimulation for the purpose of augmenting fracture healing in humans. Of these, one was a direct current electrical stimulation study. Six studies utilized pulsed electromagnetic field therapy and five used capacitive coupling. When examining these studies, the device specifications were heterogenous and often incomplete in what they reported, which rendered studies unrepeatable. The stimulation protocols also varied greatly study to study. To demonstrate efficacy of electrical stimulation for fractures, the authors recommend isolating a fracture type that is prone to nonunion to maximize the electrical stimulation effect, a homogenous study population so as to not dilute the effect of electrical stimulation, and increasing scientific rigor in the form of pre-registration, blinding, and sham controls. Finally, we introduce the critical components of minimum device specification reporting for repeatability of studies of this type.
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Affiliation(s)
- Peter J. Nicksic
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - D’Andrea T. Donnelly
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin—Madison, Madison, WI, United States
| | - Allison J. Setiz
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- APT Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe), University of Wisconsin—Madison, Madison, WI, United States
- Department of Neurological Surgery, University of Wisconsin—Madison, Madison, WI, United States
| | - Aaron M. Dingle
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Samuel O. Poore
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- *Correspondence: Samuel O. Poore,
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15
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Nicksic PJ, Donnelly DT, Hesse M, Bedi S, Verma N, Seitz AJ, Shoffstall AJ, Ludwig KA, Dingle AM, Poore SO. Electronic Bone Growth Stimulators for Augmentation of Osteogenesis in In Vitro and In Vivo Models: A Narrative Review of Electrical Stimulation Mechanisms and Device Specifications. Front Bioeng Biotechnol 2022; 10:793945. [PMID: 35237571 PMCID: PMC8882968 DOI: 10.3389/fbioe.2022.793945] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 01/17/2022] [Indexed: 01/23/2023] Open
Abstract
Since the piezoelectric quality of bone was discovered in 1957, scientists have applied exogenous electrical stimulation for the purpose of healing. Despite the efforts made over the past 60 years, electronic bone growth stimulators are not in common clinical use. Reasons for this include high cost and lack of faith in the efficacy of bone growth stimulators on behalf of clinicians. The purpose of this narrative review is to examine the preclinical body of literature supporting electrical stimulation and its effect on bone properties and elucidate gaps in clinical translation with an emphasis on device specifications and mechanisms of action. When examining these studies, trends become apparent. In vitro and small animal studies are successful in inducing osteogenesis with all electrical stimulation modalities: direct current, pulsed electromagnetic field, and capacitive coupling. However, large animal studies are largely unsuccessful with the non-invasive modalities. This may be due to issues of scale and thickness of tissue planes with varying levels of resistivity, not present in small animal models. Additionally, it is difficult to draw conclusions from studies due to the varying units of stimulation strength and stimulation protocols and incomplete device specification reporting. To better understand the disconnect between the large and small animal model, the authors recommend increasing scientific rigor for these studies and reporting a novel minimum set of parameters depending on the stimulation modality.
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Affiliation(s)
- Peter J. Nicksic
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - D’Andrea T. Donnelly
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Madison Hesse
- Des Moines University School of Medicine and Health Sciences, Des Moines, IA, United States
| | - Simran Bedi
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States,Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, WI, United States
| | - Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, WI, United States,Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States
| | - Allison J. Seitz
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin—Madison, Madison, WI, United States,Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States
| | - Aaron M. Dingle
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Samuel O. Poore
- Division of Plastic Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States,*Correspondence: Samuel O. Poore,
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16
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Verma N, Graham RD, Mudge J, Trevathan JK, Franke M, Shoffstall AJ, Williams J, Dalrymple AN, Fisher LE, Weber DJ, Lempka SF, Ludwig KA. Augmented Transcutaneous Stimulation Using an Injectable Electrode: A Computational Study. Front Bioeng Biotechnol 2022; 9:796042. [PMID: 34988068 PMCID: PMC8722711 DOI: 10.3389/fbioe.2021.796042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/25/2021] [Indexed: 11/13/2022] Open
Abstract
Minimally invasive neuromodulation technologies seek to marry the neural selectivity of implantable devices with the low-cost and non-invasive nature of transcutaneous electrical stimulation (TES). The Injectrode® is a needle-delivered electrode that is injected onto neural structures under image guidance. Power is then transcutaneously delivered to the Injectrode using surface electrodes. The Injectrode serves as a low-impedance conduit to guide current to the deep on-target nerve, reducing activation thresholds by an order of magnitude compared to using only surface stimulation electrodes. To minimize off-target recruitment of cutaneous fibers, the energy transfer efficiency from the surface electrodes to the Injectrode must be optimized. TES energy is transferred to the Injectrode through both capacitive and resistive mechanisms. Electrostatic finite element models generally used in TES research consider only the resistive means of energy transfer by defining tissue conductivities. Here, we present an electroquasistatic model, taking into consideration both the conductivity and permittivity of tissue, to understand transcutaneous power delivery to the Injectrode. The model was validated with measurements taken from (n = 4) swine cadavers. We used the validated model to investigate system and anatomic parameters that influence the coupling efficiency of the Injectrode energy delivery system. Our work suggests the relevance of electroquasistatic models to account for capacitive charge transfer mechanisms when studying TES, particularly when high-frequency voltage components are present, such as those used for voltage-controlled pulses and sinusoidal nerve blocks.
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Affiliation(s)
- Nishant Verma
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Translational Neuroengineering (WITNe)-Madison, Madison, WI, United States
| | - Robert D Graham
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States
| | - Jonah Mudge
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Translational Neuroengineering (WITNe)-Madison, Madison, WI, United States
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Translational Neuroengineering (WITNe)-Madison, Madison, WI, United States
| | | | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Justin Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Translational Neuroengineering (WITNe)-Madison, Madison, WI, United States
| | - Ashley N Dalrymple
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Lee E Fisher
- Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Douglas J Weber
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States.,Rehab Neural Engineering Labs (RNEL), Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States
| | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States.,Biointerfaces Institute, University of Michigan, Ann Arbor, MI, United States.,Department of Anesthesiology, University of Michigan, Ann Arbor, MI, United States
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States.,Wisconsin Institute for Translational Neuroengineering (WITNe)-Madison, Madison, WI, United States.,Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States
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17
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Settell ML, Skubal AC, Chen RCH, Kasole M, Knudsen BE, Nicolai EN, Huang C, Zhou C, Trevathan JK, Upadhye A, Kolluru C, Shoffstall AJ, Williams JC, Suminski AJ, Grill WM, Pelot NA, Chen S, Ludwig KA. In vivo Visualization of Pig Vagus Nerve "Vagotopy" Using Ultrasound. Front Neurosci 2021; 15:676680. [PMID: 34899151 PMCID: PMC8660563 DOI: 10.3389/fnins.2021.676680] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 11/01/2021] [Indexed: 02/05/2023] Open
Abstract
Background: Placement of the clinical vagus nerve stimulating cuff is a standard surgical procedure based on anatomical landmarks, with limited patient specificity in terms of fascicular organization or vagal anatomy. As such, the therapeutic effects are generally limited by unwanted side effects of neck muscle contractions, demonstrated by previous studies to result from stimulation of (1) motor fibers near the cuff in the superior laryngeal and (2) motor fibers within the cuff projecting to the recurrent laryngeal. Objective: Conventional non-invasive ultrasound, where the transducer is placed on the surface of the skin, has been previously used to visualize the vagus with respect to other landmarks such as the carotid and internal jugular vein. However, it lacks sufficient resolution to provide details about the vagus fascicular organization, or detail about smaller neural structures such as the recurrent and superior laryngeal branch responsible for therapy limiting side effects. Here, we characterize the use of ultrasound with the transducer placed in the surgical pocket to improve resolution without adding significant additional risk to the surgical procedure in the pig model. Methods: Ultrasound images were obtained from a point of known functional organization at the nodose ganglia to the point of placement of stimulating electrodes within the surgical window. Naïve volunteers with minimal training were then asked to use these ultrasound videos to trace afferent groupings of fascicles from the nodose to their location within the surgical window where a stimulating cuff would normally be placed. Volunteers were asked to select a location for epineural electrode placement away from the fascicles containing efferent motor nerves responsible for therapy limiting side effects. 2-D and 3-D reconstructions of the ultrasound were directly compared to post-mortem histology in the same animals. Results: High-resolution ultrasound from the surgical pocket enabled 2-D and 3-D reconstruction of the cervical vagus and surrounding structures that accurately depicted the functional vagotopy of the pig vagus nerve as confirmed via histology. Although resolution was not sufficient to match specific fascicles between ultrasound and histology 1 to 1, it was sufficient to trace fascicle groupings from a point of known functional organization at the nodose ganglia to their locations within the surgical window at stimulating electrode placement. Naïve volunteers were able place an electrode proximal to the sensory afferent grouping of fascicles and away from the motor nerve efferent grouping of fascicles in each subject (n = 3). Conclusion: The surgical pocket itself provides a unique opportunity to obtain higher resolution ultrasound images of neural targets responsible for intended therapeutic effect and limiting off-target effects. We demonstrate the increase in resolution is sufficient to aid patient-specific electrode placement to optimize outcomes. This simple technique could be easily adopted for multiple neuromodulation targets to better understand how patient specific anatomy impacts functional outcomes.
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Affiliation(s)
- Megan L. Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
| | - Aaron C. Skubal
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
| | - Rex C. H. Chen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
| | - Maïsha Kasole
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
| | - Bruce E. Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
| | - Evan N. Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, United States
| | - Chengwu Huang
- Department of Radiology, Mayo Clinic, Rochester, MN, United States
| | - Chenyun Zhou
- Department of Radiology, Mayo Clinic, Rochester, MN, United States
- Department of Ultrasound, West China Hospital of Sichuan University, Chengdu, China
| | - James K. Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
| | - Aniruddha Upadhye
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Chaitanya Kolluru
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States
| | - Justin C. Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States
| | - Aaron J. Suminski
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States
| | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States
- Department of Neurobiology, Duke University, Durham, NC, United States
- Department of Neurosurgery, Duke University, Durham, NC, United States
| | - Nicole A. Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States
| | - Shigao Chen
- Department of Radiology, Mayo Clinic, Rochester, MN, United States
| | - Kip A. Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, Madison, WI, United States
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States
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18
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Dalrymple AN, Ting JE, Bose R, Trevathan JK, Nieuwoudt S, Lempka SF, Franke M, Ludwig KA, Shoffstall AJ, Fisher LE, Weber DJ. Stimulation of the dorsal root ganglion using an Injectrode ®. J Neural Eng 2021; 18. [PMID: 34650008 DOI: 10.1088/1741-2552/ac2ffb] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/14/2021] [Indexed: 01/15/2023]
Abstract
Objective. The goal of this work was to compare afferent fiber recruitment by dorsal root ganglion (DRG) stimulation using an injectable polymer electrode (Injectrode®) and a more traditional cylindrical metal electrode.Approach. We exposed the L6 and L7 DRG in four cats via a partial laminectomy or burr hole. We stimulated the DRG using an Injectrode or a stainless steel (SS) electrode using biphasic pulses at three different pulse widths (80, 150, 300μs) and pulse amplitudes spanning the range used for clinical DRG stimulation. We recorded antidromic evoked compound action potentials (ECAPs) in the sciatic, tibial, and common peroneal nerves using nerve cuffs. We calculated the conduction velocity of the ECAPs and determined the charge-thresholds and recruitment rates for ECAPs from Aα, Aβ, and Aδfibers. We also performed electrochemical impedance spectroscopy measurements for both electrode types.Main results. The ECAP thresholds for the Injectrode did not differ from the SS electrode across all primary afferents (Aα, Aβ, Aδ) and pulse widths; charge-thresholds increased with wider pulse widths. Thresholds for generating ECAPs from Aβfibers were 100.0 ± 32.3 nC using the SS electrode, and 90.9 ± 42.9 nC using the Injectrode. The ECAP thresholds from the Injectrode were consistent over several hours of stimulation. The rate of recruitment was similar between the Injectrodes and SS electrode and decreased with wider pulse widths.Significance. The Injectrode can effectively excite primary afferents when used for DRG stimulation within the range of parameters used for clinical DRG stimulation. The Injectrode can be implanted through minimally invasive techniques while achieving similar neural activation to conventional electrodes, making it an excellent candidate for future DRG stimulation and neuroprosthetic applications.
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Affiliation(s)
- Ashley N Dalrymple
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Wean 1323, Pittsburgh, PA 15217, United States of America.,Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, 15217, United States of America
| | - Jordyn E Ting
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, 15217, United States of America.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, 15217, United States of America
| | - Rohit Bose
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, 15217, United States of America.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, 15217, United States of America
| | - James K Trevathan
- Departments of Biomedical Engineering and Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | | | - Scott F Lempka
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
| | | | - Kip A Ludwig
- Departments of Biomedical Engineering and Neurological Surgery, University of Wisconsin-Madison, Madison, WI, United States of America.,Neuronoff Inc., Cleveland, OH, United States of America.,Wisconsin Institute for Translational Neuroengineering (WITNe), Madison, WI, United States of America
| | - Andrew J Shoffstall
- Neuronoff Inc., Cleveland, OH, United States of America.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
| | - Lee E Fisher
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, 15217, United States of America.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, 15217, United States of America.,Department of Physical Medicine and Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - Douglas J Weber
- Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Wean 1323, Pittsburgh, PA 15217, United States of America.,Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, 15217, United States of America.,Center for Neural Basis of Cognition, Pittsburgh, PA, 15217, United States of America.,Neuroscience Institute, Carnegie Mellon University, 5000 Forbes Ave, Wean 1323, Pittsburgh, PA 15217, United States of America
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19
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Dalrymple AN, Ting JE, Bose R, Nieuwoudt S, Franke M, Ludwig KA, Shoffstall AJ, Fisher LE, Weber DJ. Recruitment of Primary Afferents by Dorsal Root Ganglion Stimulation using the Injectrode. Int IEEE EMBS Conf Neural Eng 2021; 2021:609-612. [PMID: 34630868 DOI: 10.1109/ner49283.2021.9441420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Chronic pain affects millions of people in the United States and pharmacological treatments have been ineffective. Dorsal root ganglion (DRG) stimulation is a neuromodulation method that delivers electrical stimulation to the DRG to relieve pain. DRG electrodes are rigid and cylindrical. The implantation of DRG electrodes requires a technically-challenging surgery that involves steering electrodes laterally towards the DRG. The Injectrode is an injectable conductive polymer that cures in place and is capable of delivering electrical current to stimulate neural tissue. We used the Injectrode to stimulate the L6 and L7 DRG in cats, measuring neural responses evoked in the sciatic, tibial, and common peroneal nerves to measure the thresholds for activating fibers. A cylindrical stainless-steel electrode was used for comparison. Thresholds were 38% higher with the Injectrode versus stainless-steel, likely owing to its larger contact surface area with the DRG. Both Aα and Aβ sensory fibers were activated using DRG stimulation. The Injectrode has the potential to offer a new and simple method for DRG stimulation that can potentially offer more complete coverage of the DRG.
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Affiliation(s)
- Ashley N Dalrymple
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Jordyn E Ting
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rohit Bose
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
| | | | | | | | | | - Lee E Fisher
- Rehab Neural Engineering Labs, University of Pittsburgh, Pittsburgh, PA, USA
| | - Douglas J Weber
- Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA, USA
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20
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Settell ML, Pelot NA, Knudsen BE, Dingle AM, McConico AL, Nicolai EN, Trevathan JK, Ezzell JA, Ross EK, Gustafson KJ, Shoffstall AJ, Williams JC, Zeng W, Poore SO, Populin LC, Suminski AJ, Grill WM, Ludwig KA. Corrigendum: Functional vagotopy in the cervical vagus nerve of the domestic pig: implications for the study of vagus nerve stimulation (2020 J. Neural Eng.17 026022). J Neural Eng 2021; 18. [PMID: 34096889 DOI: 10.1088/1741-2552/ac01ff] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 05/17/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Megan L Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Bruce E Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States of America
| | - Aaron M Dingle
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Andrea L McConico
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States of America
| | - Evan N Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
| | - J Ashley Ezzell
- Histology Research Core, University of North Carolina School of Medicine, Chapel Hill, NC, United States of America.,Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, NC, United States of America
| | - Erika K Ross
- Abbott Neuromodulation, Plano, TX, United States of America
| | - Kenneth J Gustafson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Weifeng Zeng
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Samuel O Poore
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America.,Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America.,University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
| | - Luis C Populin
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Aaron J Suminski
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America.,Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States of America.,Department of Neurobiology, Duke University, Durham, NC, United States of America.,Department of Neurosurgery, Duke University, Durham, NC, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America.,Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
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21
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Nicolai EN, Settell ML, Knudsen BE, McConico AL, Gosink BA, Trevathan JK, Baumgart IW, Ross EK, Pelot NA, Grill WM, Gustafson KJ, Shoffstall AJ, Williams JC, Ludwig KA. Sources of off-target effects of vagus nerve stimulation using the helical clinical lead in domestic pigs. J Neural Eng 2020; 17:046017. [PMID: 32554888 PMCID: PMC7717671 DOI: 10.1088/1741-2552/ab9db8] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Objective Clinical data suggest that efficacious vagus nerve stimulation (VNS) is limited by side effects such as cough and dyspnea that have stimulation thresholds lower than those for therapeutic outcomes. VNS side effects are putatively caused by activation of nearby muscles within the neck, via direct muscle activation or activation of nerve fibers innervating those muscles. Our goal was to determine the thresholds at which various VNS-evoked effects occur in the domestic pig—an animal model with vagus anatomy similar to human—using the bipolar helical lead deployed clinically. Approach Intrafascicular electrodes were placed within the vagus nerve to record electroneurographic (ENG) responses, and needle electrodes were placed in the vagal-innervated neck muscles to record electromyographic (EMG) responses. Main results Contraction of the cricoarytenoid muscle occurred at low amplitudes (~0.3 mA) and resulted from activation of motor nerve fibers in the cervical vagus trunk within the electrode cuff which bifurcate into the recurrent laryngeal branch of the vagus. At higher amplitudes (~1.4 mA), contraction of the cricoarytenoid and cricothyroid muscles was generated by current leakage outside the cuff to activate motor nerve fibers running within the nearby superior laryngeal branch of the vagus. Activation of these muscles generated artifacts in the ENG recordings that may be mistaken for compound action potentials representing slowly conducting Aδ-, B-, and C-fibers. Significance Our data resolve conflicting reports of the stimulation amplitudes required for C-fiber activation in large animal studies (>10 mA) and human studies (<250 μA). After removing muscle-generated artifacts, ENG signals with post-stimulus latencies consistent with Aδ- and B-fibers occurred in only a small subset of animals, and these signals had similar thresholds to those that caused bradycardia. By identifying specific neuroanatomical pathways that cause off-target effects and characterizing the stimulation dose-response curves for on- and off-target effects, we hope to guide interpretation and optimization of clinical VNS.
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Affiliation(s)
- Evan N Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Megan L Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Bruce E Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Andrea L McConico
- Department of Neurosurgery, Mayo Clinic, Rochester, MN, United States of America
| | - Brian A Gosink
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Ian W Baumgart
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Erika K Ross
- Abbott Neuromodulation, Plano, TX, United States of America
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Kenneth J Gustafson
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States of America
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute of Neuroengineering (WITNe), University of Wisconsin-Madison, WI, United States of America
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22
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Settell ML, Pelot NA, Knudsen BE, Dingle AM, McConico AL, Nicolai EN, Trevathan JK, Ezzell JA, Ross EK, Gustafson KJ, Shoffstall AJ, Williams JC, Zeng W, Poore SO, Populin LC, Suminski AJ, Grill WM, Ludwig KA. Functional vagotopy in the cervical vagus nerve of the domestic pig: implications for the study of vagus nerve stimulation. J Neural Eng 2020; 17:026022. [PMID: 32108590 PMCID: PMC7306215 DOI: 10.1088/1741-2552/ab7ad4] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Given current clinical interest in vagus nerve stimulation (VNS), there are surprisingly few studies characterizing the anatomy of the vagus nerve in large animal models as it pertains to on-and off-target engagement of local fibers. We sought to address this gap by evaluating vagal anatomy in the pig, whose vagus nerve organization and size approximates the human vagus nerve. APPROACH Here we combined microdissection, histology, and immunohistochemistry to provide data on key features across the cervical vagus nerve in a swine model, and compare our results to other animal models (mouse, rat, dog, non-human primate) and humans. MAIN RESULTS In a swine model we quantified the nerve diameter, number and diameter of fascicles, and distance of fascicles from the epineural surface where stimulating electrodes are placed. We also characterized the relative locations of the superior and recurrent laryngeal branches of the vagus nerve that have been implicated in therapy limiting side effects with common electrode placement. We identified key variants across the cohort that may be important for VNS with respect to changing sympathetic/parasympathetic tone, such as cross-connections to the sympathetic trunk. We discovered that cell bodies of pseudo-unipolar cells aggregate together to form a very distinct grouping within the nodose ganglion. This distinct grouping gives rise to a larger number of smaller fascicles as one moves caudally down the vagus nerve. This often leads to a distinct bimodal organization, or 'vagotopy'. This vagotopy was supported by immunohistochemistry where approximately half of the fascicles were immunoreactive for choline acetyltransferase, and reactive fascicles were generally grouped in one half of the nerve. SIGNIFICANCE The vagotopy observed via histology may be advantageous to exploit in design of electrodes/stimulation paradigms. We also placed our data in context of historic and recent histology spanning multiple models, thus providing a comprehensive resource to understand similarities and differences across species.
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Affiliation(s)
- Megan L Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
| | - Nicole A Pelot
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
| | - Bruce E Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States of America
| | - Aaron M Dingle
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Andrea L McConico
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, United States of America
| | - Evan N Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
| | - James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Mayo Clinic, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, United States of America
| | - J Ashley Ezzell
- Histology Research Core, University of North Carolina School of Medicine, Durham, NC, United States of America
- Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Durham, NC, United States of America
| | - Erika K Ross
- Abbott Neuromodulation, Plano, TX, United States of America
| | - Kenneth J Gustafson
- Department of Biomedical Engineering, Western Reserve University, Cleveland, OH, United States of America
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Western Reserve University, Cleveland, OH, United States of America
- Louis Stokes Cleveland VA Medical Center, Cleveland, OH, United States of America
| | - Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Weifeng Zeng
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Samuel O Poore
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Division of Plastic Surgery, Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Surgery, University of Wisconsin-Madison, Madison, WI, United States of America
- University of Wisconsin School of Medicine and Public Health, Madison, WI, United States of America
| | - Luis C Populin
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Aaron J Suminski
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Warren M Grill
- Department of Biomedical Engineering, Duke University, Durham, NC, United States of America
- Department of Electrical and Computer Engineering, Duke University, Durham, NC, United States of America
- Department of Neurobiology, Duke University, Durham, NC, United States of America
- Department of Neurosurgery, Duke University, Durham, NC, United States of America
| | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States of America
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, United States of America
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23
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Shoffstall AJ, Capadona JR. Bioelectronic Neural Implants. Biomater Sci 2020. [DOI: 10.1016/b978-0-12-816137-1.00073-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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24
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Trevathan JK, Baumgart IW, Nicolai EN, Gosink BA, Asp AJ, Settell ML, Polaconda SR, Malerick KD, Brodnick SK, Zeng W, Knudsen BE, McConico AL, Sanger Z, Lee JH, Aho JM, Suminski AJ, Ross EK, Lujan JL, Weber DJ, Williams JC, Franke M, Ludwig KA, Shoffstall AJ. Neural Interfaces: An Injectable Neural Stimulation Electrode Made from an In‐Body Curing Polymer/Metal Composite (Adv. Healthcare Mater. 23/2019). Adv Healthc Mater 2019. [DOI: 10.1002/adhm.201970090] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- James K. Trevathan
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Mayo Clinic Graduate School of Biomedical SciencesMayo Clinic Rochester MN 55902 USA
| | - Ian W. Baumgart
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
| | - Evan N. Nicolai
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Mayo Clinic Graduate School of Biomedical SciencesMayo Clinic Rochester MN 55902 USA
| | - Brian A. Gosink
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Department of NeurosurgeryUniversity of Wisconsin‐Madison Madison WI 53706 USA
| | - Anders J. Asp
- Mayo Clinic Graduate School of Biomedical SciencesMayo Clinic Rochester MN 55902 USA
| | - Megan L. Settell
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Mayo Clinic Graduate School of Biomedical SciencesMayo Clinic Rochester MN 55902 USA
| | - Shyam R. Polaconda
- Department of Biomedical EngineeringCase Western Reserve University Cleveland OH 44106 USA
| | - Kevin D. Malerick
- Department of Biomedical EngineeringCase Western Reserve University Cleveland OH 44106 USA
| | - Sarah K. Brodnick
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
| | - Weifeng Zeng
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
| | - Bruce E. Knudsen
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Department of Neurologic SurgeryMayo Clinic Rochester MN 55902 USA
| | | | - Zachary Sanger
- Department of Neurologic SurgeryMayo Clinic Rochester MN 55902 USA
| | - Jannifer H. Lee
- Mayo Clinic Graduate School of Biomedical SciencesMayo Clinic Rochester MN 55902 USA
| | - Johnathon M. Aho
- Division of General Thoracic SurgeryMayo Clinic Rochester MN 55902 USA
- Physiology and Biomedical EngineeringMayo Clinic Rochester MN 55902 USA
| | - Aaron J. Suminski
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
| | - Erika K. Ross
- Department of Neurologic SurgeryMayo Clinic Rochester MN 55902 USA
| | - Jose L. Lujan
- Mayo Clinic Graduate School of Biomedical SciencesMayo Clinic Rochester MN 55902 USA
- Department of Neurologic SurgeryMayo Clinic Rochester MN 55902 USA
- Physiology and Biomedical EngineeringMayo Clinic Rochester MN 55902 USA
| | - Douglas J. Weber
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Department of BioengineeringUniversity of Pittsburgh Pittsburgh PA 15260 USA
| | - Justin C. Williams
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
| | | | - Kip A. Ludwig
- Department of Biomedical EngineeringUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Department of NeurosurgeryUniversity of Wisconsin‐Madison Madison WI 53706 USA
- Department of Neurologic SurgeryMayo Clinic Rochester MN 55902 USA
- Neuronoff Inc. Valencia CA 91354 USA
| | - Andrew J. Shoffstall
- Department of Biomedical EngineeringCase Western Reserve University Cleveland OH 44106 USA
- Neuronoff Inc. Valencia CA 91354 USA
- Advanced Platform Technologies CenterLouis Stokes Cleveland Veterans Affairs Medical Center Cleveland OH 44106 USA
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Trevathan JK, Baumgart IW, Nicolai EN, Gosink BA, Asp AJ, Settell ML, Polaconda SR, Malerick KD, Brodnick SK, Zeng W, Knudsen BE, McConico AL, Sanger Z, Lee JH, Aho JM, Suminski AJ, Ross EK, Lujan JL, Weber DJ, Williams JC, Franke M, Ludwig KA, Shoffstall AJ. An Injectable Neural Stimulation Electrode Made from an In-Body Curing Polymer/Metal Composite. Adv Healthc Mater 2019; 8:e1900892. [PMID: 31697052 PMCID: PMC10425988 DOI: 10.1002/adhm.201900892] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 09/20/2019] [Indexed: 12/15/2022]
Abstract
Implanted neural stimulation and recording devices hold vast potential to treat a variety of neurological conditions, but the invasiveness, complexity, and cost of the implantation procedure greatly reduce access to an otherwise promising therapeutic approach. To address this need, a novel electrode that begins as an uncured, flowable prepolymer that can be injected around a neuroanatomical target to minimize surgical manipulation is developed. Referred to as the Injectrode, the electrode conforms to target structures forming an electrically conductive interface which is orders of magnitude less stiff than conventional neuromodulation electrodes. To validate the Injectrode, detailed electrochemical and microscopy characterization of its material properties is performed and the feasibility of using it to stimulate the nervous system electrically in rats and swine is validated. The silicone-metal-particle composite performs very similarly to pure wire of the same metal (silver) in all measures, including exhibiting a favorable cathodic charge storage capacity (CSCC ) and charge injection limits compared to the clinical LivaNova stimulation electrode and silver wire electrodes. By virtue of its simplicity, the Injectrode has the potential to be less invasive, more robust, and more cost-effective than traditional electrode designs, which could increase the adoption of neuromodulation therapies for existing and new indications.
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Affiliation(s)
- James K Trevathan
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55902, USA
| | - Ian W Baumgart
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Evan N Nicolai
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55902, USA
| | - Brian A Gosink
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Anders J Asp
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55902, USA
| | - Megan L Settell
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55902, USA
| | - Shyam R Polaconda
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Kevin D Malerick
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Sarah K Brodnick
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Weifeng Zeng
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Bruce E Knudsen
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55902, USA
| | - Andrea L McConico
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55902, USA
| | - Zachary Sanger
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55902, USA
| | - Jannifer H Lee
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55902, USA
| | - Johnathon M Aho
- Division of General Thoracic Surgery, Mayo Clinic, Rochester, MN, 55902, USA
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55902, USA
| | - Aaron J Suminski
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Erika K Ross
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55902, USA
| | - Jose L Lujan
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, 55902, USA
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55902, USA
- Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, 55902, USA
| | - Douglas J Weber
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Justin C Williams
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | | | - Kip A Ludwig
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Neurosurgery, University of Wisconsin-Madison, Madison, WI, 53706, USA
- Department of Neurologic Surgery, Mayo Clinic, Rochester, MN, 55902, USA
- Neuronoff Inc., Valencia, CA, 91354, USA
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, 44106, USA
- Neuronoff Inc., Valencia, CA, 91354, USA
- Advanced Platform Technologies Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, OH, 44106, USA
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Hermann JK, Ravikumar M, Shoffstall AJ, Ereifej ES, Kovach KM, Chang J, Soffer A, Wong C, Srivastava V, Smith P, Protasiewicz G, Jiang J, Selkirk SM, Miller RH, Sidik S, Ziats NP, Taylor DM, Capadona JR. Inhibition of the cluster of differentiation 14 innate immunity pathway with IAXO-101 improves chronic microelectrode performance. J Neural Eng 2019; 15:025002. [PMID: 29219114 DOI: 10.1088/1741-2552/aaa03e] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Neuroinflammatory mechanisms are hypothesized to contribute to intracortical microelectrode failures. The cluster of differentiation 14 (CD14) molecule is an innate immunity receptor involved in the recognition of pathogens and tissue damage to promote inflammation. The goal of the study was to investigate the effect of CD14 inhibition on intracortical microelectrode recording performance and tissue integration. APPROACH Mice implanted with intracortical microelectrodes in the motor cortex underwent electrophysiological characterization for 16 weeks, followed by endpoint histology. Three conditions were examined: (1) wildtype control mice, (2) knockout mice lacking CD14, and (3) wildtype control mice administered a small molecule inhibitor to CD14 called IAXO-101. MAIN RESULTS The CD14 knockout mice exhibited acute but not chronic improvements in intracortical microelectrode performance without significant differences in endpoint histology. Mice receiving IAXO-101 exhibited significant improvements in recording performance over the entire 16 week duration without significant differences in endpoint histology. SIGNIFICANCE Full removal of CD14 is beneficial at acute time ranges, but limited CD14 signaling is beneficial at chronic time ranges. Innate immunity receptor inhibition strategies have the potential to improve long-term intracortical microelectrode performance.
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Affiliation(s)
- John K Hermann
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Rehabilitation Research and Development, 10701 East Blvd. Mail Stop 151 AW/APT, Cleveland OH 44106, United States of America. Department of Biomedical Engineering, Case Western Reserve University, School of Engineering, 2071 Martin Luther King Jr Drive, Wickenden Bldg, Cleveland OH 44106, United States of America
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Abstract
Neural probes that mimic the subcellular structural features and mechanical properties of neurons assimilate across several structures of the brain to provide chronically stable neural recordings in a mouse model.
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Affiliation(s)
- Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, School of Engineering, Cleveland, OH, USA.
- Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, Rehabilitation Research and Development, Cleveland, OH, USA.
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, School of Engineering, Cleveland, OH, USA
- Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, Rehabilitation Research and Development, Cleveland, OH, USA
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA
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Lindner SC, Yu M, Capadona JR, Shoffstall AJ. A graphical user interface to assess the neuroinflammatory response to intracortical microelectrodes. J Neurosci Methods 2019; 317:141-148. [PMID: 30664915 DOI: 10.1016/j.jneumeth.2019.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 01/10/2019] [Accepted: 01/11/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Brain-implanted devices, including intracortical microelectrodes, are used in neuroscience applications ranging from research to rehabilitation and beyond. Significant efforts are focused on developing new device designs and insertion strategies that mitigate initial trauma and subsequent neuroinflammation that occurs as a result of implantation. A frequently published metric is the neuroinflammatory response quantified as a function of distance from the interface edge, using fluorescent immunohistochemical markers. NEW METHOD Here, we sought to develop a graphical user interface software in Matlab to provide an objective, repeatable, and easy-to-use method for analyzing fluorescence immunohistochemistry images of neuroinflammation. The user interface allows for efficient batch-processing and review of images, and incorporates zoom and contrast features to improve the accuracy of identifying the 'region of interest' (ROI). RESULTS The software was validated against previously published results and demonstrated equivalent scientific conclusions. Furthermore, a comparison between novice and expert users demonstrated consistency across levels of training and a rapid learning-curve. COMPARISON WITH EXISTING METHOD(S) Existing methods published in the intracortical microelectrode literature include a wide variety of procedures within ImageJ and Matlab. However, specific procedural details are often lacking. CONCLUSIONS The distribution of the methodology may promote efficiency and reproducibility across the field seeking to characterize the tissue response to implanted neural interfaces. It may also serve as a template for researchers seeking to perform other types of histological quantification as a function of distance from an ROI.
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Affiliation(s)
- Sydney C Lindner
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States
| | - Marina Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, United States
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, United States
| | - Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, United States; Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, OH, United States.
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Bedell HW, Song S, Li X, Molinich E, Lin S, Stiller A, Danda V, Ecker M, Shoffstall AJ, Voit WE, Pancrazio JJ, Capadona JR. Understanding the Effects of Both CD14-Mediated Innate Immunity and Device/Tissue Mechanical Mismatch in the Neuroinflammatory Response to Intracortical Microelectrodes. Front Neurosci 2018; 12:772. [PMID: 30429766 PMCID: PMC6220032 DOI: 10.3389/fnins.2018.00772] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Accepted: 10/04/2018] [Indexed: 01/02/2023] Open
Abstract
Intracortical microelectrodes record neuronal activity of individual neurons within the brain, which can be used to bridge communication between the biological system and computer hardware for both research and rehabilitation purposes. However, long-term consistent neural recordings are difficult to achieve, in large part due to the neuroinflammatory tissue response to the microelectrodes. Prior studies have identified many factors that may contribute to the neuroinflammatory response to intracortical microelectrodes. Unfortunately, each proposed mechanism for the prolonged neuroinflammatory response has been investigated independently, while it is clear that mechanisms can overlap and be difficult to isolate. Therefore, we aimed to determine whether the dual targeting of the innate immune response by inhibiting innate immunity pathways associated with cluster of differentiation 14 (CD14), and the mechanical mismatch could improve the neuroinflammatory response to intracortical microelectrodes. A thiol-ene probe that softens on contact with the physiological environment was used to reduce mechanical mismatch. The thiol-ene probe was both softer and larger in size than the uncoated silicon control probe. Cd14-/- mice were used to completely inhibit contribution of CD14 to the neuroinflammatory response. Contrary to the initial hypothesis, dual targeting worsened the neuroinflammatory response to intracortical probes. Therefore, probe material and CD14 deficiency were independently assessed for their effect on inflammation and neuronal density by implanting each microelectrode type in both wild-type control and Cd14-/- mice. Histology results show that 2 weeks after implantation, targeting CD14 results in higher neuronal density and decreased glial scar around the probe, whereas the thiol-ene probe results in more microglia/macrophage activation and greater blood-brain barrier (BBB) disruption around the probe. Chronic histology demonstrate no differences in the inflammatory response at 16 weeks. Over acute time points, results also suggest immunomodulatory approaches such as targeting CD14 can be utilized to decrease inflammation to intracortical microelectrodes. The results obtained in the current study highlight the importance of not only probe material, but probe size, in regard to neuroinflammation.
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Affiliation(s)
- Hillary W. Bedell
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, Rehab. R&D, Cleveland, OH, United States
| | - Sydney Song
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, Rehab. R&D, Cleveland, OH, United States
| | - Xujia Li
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Emily Molinich
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Shushen Lin
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH, United States
| | - Allison Stiller
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Vindhya Danda
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
- Center for Engineering Innovation, The University of Texas at Dallas, Richardson, TX, United States
| | - Melanie Ecker
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
- Center for Engineering Innovation, The University of Texas at Dallas, Richardson, TX, United States
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, Rehab. R&D, Cleveland, OH, United States
| | - Walter E. Voit
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
- Center for Engineering Innovation, The University of Texas at Dallas, Richardson, TX, United States
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX, United States
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Joseph J. Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, United States
| | - Jeffrey R. Capadona
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, OH, United States
- Advanced Platform Technology Center, L. Stokes Cleveland VA Medical Center, Rehab. R&D, Cleveland, OH, United States
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Shoffstall AJ, Ecker M, Danda V, Joshi-Imre A, Stiller A, Yu M, Paiz JE, Mancuso E, Bedell HW, Voit WE, Pancrazio JJ, Capadona JR. Characterization of the Neuroinflammatory Response to Thiol-ene Shape Memory Polymer Coated Intracortical Microelectrodes. Micromachines (Basel) 2018; 9:E486. [PMID: 30424419 PMCID: PMC6215215 DOI: 10.3390/mi9100486] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 09/11/2018] [Accepted: 09/18/2018] [Indexed: 01/10/2023]
Abstract
Thiol-ene based shape memory polymers (SMPs) have been developed for use as intracortical microelectrode substrates. The unique chemistry provides precise control over the mechanical and thermal glass-transition properties. As a result, SMP substrates are stiff at room temperature, allowing for insertion into the brain without buckling and subsequently soften in response to body temperatures, reducing the mechanical mismatch between device and tissue. Since the surface chemistry of the materials can contribute significantly to the ultimate biocompatibility, as a first step in the characterization of our SMPs, we sought to isolate the biological response to the implanted material surface without regards to the softening mechanics. To accomplish this, we tightly controlled for bulk stiffness by comparing bare silicon 'dummy' devices to thickness-matched silicon devices dip-coated with SMP. The neuroinflammatory response was evaluated after devices were implanted in the rat cortex for 2 or 16 weeks. We observed no differences in the markers tested at either time point, except that astrocytic scarring was significantly reduced for the dip-coated implants at 16 weeks. The surface properties of non-softening thiol-ene SMP substrates appeared to be equally-tolerated and just as suitable as silicon for neural implant substrates for applications such as intracortical microelectrodes, laying the groundwork for future softer devices to improve upon the prototype device performance presented here.
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Affiliation(s)
- Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veteran Affairs Medical Center, Cleveland, OH, USA.
| | - Melanie Ecker
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veteran Affairs Medical Center, Cleveland, OH, USA.
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX, USA.
| | - Vindhya Danda
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX, USA.
- Center for Engineering Innovation, The University of Texas at Dallas, Richardson, TX, USA.
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX, USA.
| | - Alexandra Joshi-Imre
- Center for Engineering Innovation, The University of Texas at Dallas, Richardson, TX, USA.
| | - Allison Stiller
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.
| | - Marina Yu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veteran Affairs Medical Center, Cleveland, OH, USA.
| | - Jennifer E Paiz
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veteran Affairs Medical Center, Cleveland, OH, USA.
| | - Elizabeth Mancuso
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veteran Affairs Medical Center, Cleveland, OH, USA.
| | - Hillary W Bedell
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
| | - Walter E Voit
- Department of Materials Science and Engineering, The University of Texas at Dallas, Richardson, TX, USA.
- Center for Engineering Innovation, The University of Texas at Dallas, Richardson, TX, USA.
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.
- Department of Mechanical Engineering, The University of Texas at Dallas, Richardson, TX, USA.
| | - Joseph J Pancrazio
- Department of Bioengineering, The University of Texas at Dallas, Richardson, TX, USA.
| | - Jeffrey R Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veteran Affairs Medical Center, Cleveland, OH, USA.
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Dona KR, Goss-Varley M, Shoffstall AJ, Capadona JR. A Novel Single Animal Motor Function Tracking System Using Simple, Readily Available Software. J Vis Exp 2018. [PMID: 30222158 DOI: 10.3791/57917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We have recently demonstrated that implanting intracortical microelectrodes in the motor corteces of rats results in immediate and lasting motor deficits. Motor impairments were manually quantified through an open field grid test to measure the gross motor function and through a ladder test to measure the fine motor function. Here, we discuss a technique for the automated quantification of the video-recorded tests using our custom Capadona Behavioral Video Analysis System: Grid and Ladder Test, or BVAS. Leveraging simple and readily available coding software (see the Table of Materials), this program allows for the tracking of a single animal on both the open field grid and the ladder tests. In open field grid tracking, the code thresholds the video for intensity, tracks the position of the rat over the 3 min duration of the grid test, and analyzes the path. It then computes and returns measurements for the total distance traveled, the maximum velocity achieved, the number of left- and right-handed turns, and the total number of grid lines crossed by the rat. In ladder tracking, the code again thresholds the video for intensity, tracks the movement of the rat across the ladder, and returns calculated measurements including the time it took the rat to cross the ladder, the number of paw slips occurring below the plane of the ladder rungs, and the incidence of failures due to stagnation or reversals. We envision that the BVAS developed here can be employed for the analysis of motor function in a variety of applications, including many injury or disease models.
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Affiliation(s)
- Keith R Dona
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Monika Goss-Varley
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Andrew J Shoffstall
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Jeffrey R Capadona
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University;
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Goss-Varley M, Shoffstall AJ, Dona KR, McMahon JA, Lindner SC, Ereifej ES, Capadona JR. Rodent Behavioral Testing to Assess Functional Deficits Caused by Microelectrode Implantation in the Rat Motor Cortex. J Vis Exp 2018:57829. [PMID: 30176008 PMCID: PMC6128113 DOI: 10.3791/57829] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Medical devices implanted in the brain hold tremendous potential. As part of a Brain Machine Interface (BMI) system, intracortical microelectrodes demonstrate the ability to record action potentials from individual or small groups of neurons. Such recorded signals have successfully been used to allow patients to interface with or control computers, robotic limbs, and their own limbs. However, previous animal studies have shown that a microelectrode implantation in the brain not only damages the surrounding tissue but can also result in functional deficits. Here, we discuss a series of behavioral tests to quantify potential motor impairments following the implantation of intracortical microelectrodes into the motor cortex of a rat. The methods for open field grid, ladder crossing, and grip strength testing provide valuable information regarding the potential complications resulting from a microelectrode implantation. The results of the behavioral testing are correlated with endpoint histology, providing additional information on the pathological outcomes and impacts of this procedure on the adjacent tissue.
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Affiliation(s)
- Monika Goss-Varley
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Andrew J Shoffstall
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Keith R Dona
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Justin A McMahon
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Sydney C Lindner
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Evon S Ereifej
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University
| | - Jeffrey R Capadona
- Advanced Platform Technology Center, Rehabilitation Research and Development, Louis Stokes Cleveland Department of Veterans Affairs Medical Center; Department of Biomedical Engineering, Case Western Reserve University;
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Shoffstall AJ, Paiz J, Miller D, Rial G, Willis M, Menendez D, Hostler S, Capadona JR. Potential for thermal damage to the blood-brain barrier during craniotomy: implications for intracortical recording microelectrodes. J Neural Eng 2018; 15:034001. [PMID: 29205169 PMCID: PMC6482047 DOI: 10.1088/1741-2552/aa9f32] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE Our objective was to determine how readily disruption of the blood-brain barrier (BBB) occurred as a result of bone drilling during a craniotomy to implant microelectrodes in rat cortex. While the phenomenon of heat production during bone drilling is well known, practices to evade damage to the underlying brain tissue are inconsistently practiced and reported in the literature. APPROACH We conducted a review of the intracortical microelectrode literature to summarize typical approaches to mitigate drill heating during rodent craniotomies. Post mortem skull-surface and transient brain-surface temperatures were experimentally recorded using an infrared camera and thermocouple, respectively. A number of drilling conditions were tested, including varying drill speed and continuous versus intermittent contact. In vivo BBB permeability was assayed 1 h after the craniotomy procedure using Evans blue dye. MAIN RESULTS Of the reviewed papers that mentioned methods to mitigate thermal damage during craniotomy, saline irrigation was the most frequently cited (in six of seven papers). In post mortem tissues, we observed increases in skull-surface temperature ranging from +3 °C to +21 °C, dependent on drill speed. In vivo, pulsed-drilling (2 s-on/2 s-off) and slow-drilling speeds (1000 r.p.m.) were the most effective methods we studied to mitigate heating effects from drilling, while inconclusive results were obtained with saline irrigation. SIGNIFICANCE Neuroinflammation, initiated by damage to the BBB and perpetuated by the foreign body response, is thought to play a key role in premature failure of intracortical recording microelectrodes. This study demonstrates the extreme sensitivity of the BBB to overheating caused by bone drilling. To avoid damage to the BBB, the authors recommend that craniotomies be drilled with slow speeds and/or with intermittent drilling with complete removal of the drill from the skull during 'off' periods. While saline alone was ineffective at preventing overheating, its use is still recommended to remove bone dust from the surgical site and to augment other cooling methods.
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Affiliation(s)
- Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Blvd, 151 W/APT, Cleveland, OH 44106-1702, USA
| | - Jen Paiz
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - David Miller
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Griffin Rial
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Mitchell Willis
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Dhariyat Menendez
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
| | - Stephen Hostler
- Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Jeffrey R. Capadona
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44016
- Advanced Platform Technology Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, 10701 East Blvd, 151 W/APT, Cleveland, OH 44106-1702, USA
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Lavik E, Kuehn MH, Shoffstall AJ, Atkins K, Dumitrescu AV, Kwon YH. Sustained Delivery of Timolol Maleate for Over 90 Days by Subconjunctival Injection. J Ocul Pharmacol Ther 2016; 32:642-649. [PMID: 27835065 PMCID: PMC5165680 DOI: 10.1089/jop.2016.0042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 09/03/2016] [Indexed: 12/29/2022] Open
Abstract
PURPOSE Medical treatment of glaucoma relies on intraocular pressure (IOP)-lowering medications, typically administered daily by the patient. While these medications are effective when applied correctly, patient adherence is a major obstacle in glaucoma treatment. We have developed a sustained-release formulation of timolol maleate that can be injected subconjunctivally to avoid patient noncompliance. METHODS A biodegradable microsphere formulation for timolol maleate was injected subconjunctivally in normal rabbits. We measured timolol levels in tears, aqueous humor, vitreous humor, and serum of study rabbits. Furthermore, IOP profiles were recorded longitudinally. Tissue compatibility and side effects were evaluated using histochemistry. RESULTS The microsphere formulation led to measureable amounts of timolol in the aqueous humor and the tear film for up to 90 days. Timolol was not detectable in the serum at any time. A significant reduction of IOP was observed in treated eyes. Clinically, the subconjunctival administration of the microspheres was well tolerated with no signs of inflammation or infection. The absence of local inflammation was confirmed by histology. CONCLUSIONS A single subconjunctival administration of timolol microspheres achieved delivery and IOP reduction in rabbits for up to 90 days without local or systemic inflammation or toxicity. This approach has the potential to improve the management of glaucoma in patient populations, who are challenged to adhere to a regimen of daily eye drops.
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Affiliation(s)
- Erin Lavik
- Department of Chemical, Biochemical, and Environmental Engineering, University of Maryland-Baltimore County, Baltimore, Maryland
| | - Markus H. Kuehn
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa
- Iowa City Veterans Affairs Center for the Prevention and Treatment of Visual Loss, Iowa City, Iowa
| | - Andrew J. Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Kristyn Atkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio
| | - Alina V. Dumitrescu
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa
| | - Young H. Kwon
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, Iowa
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Shoffstall AJ, Gaebler JA, Kreher NC, Niecko T, Douglas D, Strong TV, Miller JL, Stafford DE, Butler MG. The High Direct Medical Costs of Prader-Willi Syndrome. J Pediatr 2016; 175:137-43. [PMID: 27283463 PMCID: PMC7464637 DOI: 10.1016/j.jpeds.2016.05.018] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Revised: 03/31/2016] [Accepted: 05/06/2016] [Indexed: 01/28/2023]
Abstract
OBJECTIVE To assess medical resource utilization associated with Prader-Willi syndrome (PWS) in the US, hypothesized to be greater relative to a matched control group without PWS. STUDY DESIGN We used a retrospective case-matched control design and longitudinal US administrative claims data (MarketScan) during a 5-year enrollment period (2009-2014). Patients with PWS were identified by Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code 759.81. Controls were matched on age, sex, and payer type. Outcomes included total, outpatient, inpatient and prescription costs. RESULTS After matching and application of inclusion/exclusion criteria, we identified 2030 patients with PWS (1161 commercial, 38 Medicare supplemental, and 831 Medicaid). Commercially insured patients with PWS (median age 10 years) had 8.8-times greater total annual direct medical costs than their counterparts without PWS (median age 10 years: median costs $14 907 vs $819; P < .0001; mean costs: $28 712 vs $3246). Outpatient care comprised the largest portion of medical resource utilization for enrollees with and without PWS (median $5605 vs $675; P < .0001; mean $11 032 vs $1804), followed by mean annual inpatient and medication costs, which were $10 879 vs $1015 (P < .001) and $6801 vs $428 (P < .001), respectively. Total annual direct medical costs were ∼42% greater for Medicaid-insured patients with PWS than their commercially insured counterparts, an increase partly explained by claims for Medicaid Waiver day and residential habilitation. CONCLUSION Direct medical resource utilization was considerably greater among patients with PWS than members without the condition. This study provides a first step toward quantifying the financial burden of PWS posed to individuals, families, and society.
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Affiliation(s)
| | | | | | | | | | - Theresa V Strong
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Jennifer L Miller
- Division of Pediatric Endocrinology, University of Florida College of Medicine, Gainesville, FL
| | - Diane E Stafford
- Division of Endocrinology, Harvard Medical School, Boston Children's Hospital, Boston, MA
| | - Merlin G Butler
- Division of Research and Genetics, Departments of Psychiatry & Behavioral Sciences and Pediatrics, Kansas University Medical Center, Kansas City, KS
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Shoffstall AJ, Everhart LM, Varley ME, Soehnlen ES, Shick AM, Ustin JS, Lavik EB. Tuning ligand density on intravenous hemostatic nanoparticles dramatically increases survival following blunt trauma. Biomacromolecules 2013; 14:2790-7. [PMID: 23841817 DOI: 10.1021/bm400619v] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Targeted nanoparticles are being pursued for a range of medical applications. Here we utilized targeted nanoparticles (synthetic platelets) to halt bleeding in acute trauma. One of the major questions that arises in the field is the role of surface ligand density in targeted nanoparticles' performance. We developed intravenous hemostatic nanoparticles (GRGDS-NP1) and previously demonstrated their ability to reduce bleeding following femoral artery injury and increase survival after lethal liver trauma in the rat. These nanoparticles are made from block copolymers, poly(lactic-co-glycolic acid)-b-poly L-lysine-b-poly(ethylene glycol). Surface-conjugated targeting ligand density can be tightly controlled with this system, and here we investigated the effect of varying density on hemostasis and biodistribution. We increased the targeting peptide (GRGDS) concentration 100-fold (GRGDS-NP100) and undertook an in vitro dose-response study using rotational thromboelastometry, finding that GRGDS-NP100 hemostatic nanoparticles were efficacious at doses at least 10 times lower than the GRGDS-NP1. These results were recapitulated in vivo, demonstrating efficacy at eight-fold lower concentration after lethal liver trauma. 1 h survival increased to 92% compared with a scrambled peptide control, 45% (OR = 14.4, 95% CI = [1.36, 143]), a saline control, 47% (OR = 13.5, 95% CI = [1.42, 125]), and GRGDS-NP1, 80% (OR = 1.30, n.s.). This work demonstrates the impact of changing synthetic platelet ligand density on hemostasis and lays the foundation for methods to determine optimal ligand concentration parameters.
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Affiliation(s)
- Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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Shoffstall AJ, Atkins KT, Groynom RE, Varley ME, Everhart LM, Lashof-Sullivan MM, Martyn-Dow B, Butler RS, Ustin JS, Lavik EB. Intravenous hemostatic nanoparticles increase survival following blunt trauma injury. Biomacromolecules 2012; 13:3850-7. [PMID: 22998772 DOI: 10.1021/bm3013023] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Trauma is the leading cause of death for people ages 1-44, with blood loss comprising 60-70% of mortality in the absence of lethal CNS or cardiac injury. Immediate intervention is critical to improving chances of survival. While there are several products to control bleeding for external and compressible wounds, including pressure dressings, tourniquets, or topical materials (e.g., QuikClot, HemCon), there are no products that can be administered in the field for internal bleeding. There is a tremendous unmet need for a hemostatic agent to address internal bleeding in the field. We have developed hemostatic nanoparticles (GRGDS-NPs) that reduce bleeding times by ~50% in a rat femoral artery injury model. Here, we investigated their impact on survival following administration in a lethal liver resection injury in rats. Administration of these hemostatic nanoparticles reduced blood loss following the liver injury and dramatically and significantly increased 1 h survival from 40 and 47% in controls (inactive nanoparticles and saline, respectively) to 80%. Furthermore, we saw no complications following administration of these nanoparticles. We further characterized the nanoparticles' effect on clotting time (CT) and maximum clot firmness (MCF) using rotational thromboelastometry (ROTEM), a clinical measurement of whole-blood coagulation. Clotting time is significantly reduced, with no change in MCF. Administration of these hemostatic nanoparticles after massive trauma may help staunch bleeding and improve survival in the critical window following injury, and this could fundamentally change trauma care.
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Affiliation(s)
- Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
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Shoffstall AJ, Taylor DM, Lavik EB. Engineering therapies in the CNS: what works and what can be translated. Neurosci Lett 2012; 519:147-54. [PMID: 22330751 DOI: 10.1016/j.neulet.2012.01.058] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 01/24/2012] [Accepted: 01/25/2012] [Indexed: 01/01/2023]
Abstract
Engineering is the art of taking what we know and using it to solve problems. As engineers, we build tool chests of approaches; we attempt to learn as much as possible about the problem at hand, and then we design, build, and test our approaches to see how they impact the system. The challenge of applying this approach to the central nervous system (CNS) is that we often do not know the details of what is needed from the biological side. New therapeutic options for treating the CNS range from new biomaterials to make scaffolds, to novel drug-delivery techniques, to functional electrical stimulation. However, the reality is that translating these new therapies and making them widely available to patients requires collaborations between scientists, engineers, clinicians, and patients to have the greatest chance of success. Here we discuss a variety of new treatment strategies and explore the pragmatic challenges involved with engineering therapies in the CNS.
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Affiliation(s)
- Andrew J Shoffstall
- Department of Biomedical Engineering, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106-1712, USA
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Shoffstall AJ, Zaszczurynski PJ, Butler RS, Damaser MS. Development of a device to standardize leak point pressure experiments in rats. Neurourol Urodyn 2008; 27:553-8. [PMID: 18551566 DOI: 10.1002/nau.20591] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
AIMS The objective of this study was to test a custom device aimed at increasing repeatability of abdominal leak point pressure (LPP) measurements in rodents. METHODS The device consisted of a soft-tipped force applicator with a force sensor which was moved in the vertical direction by a linear actuator, laser crosshairs for accurate positioning, and a hand-held wired remote control system. One expert and two novice experimenters acquired LPP measurements using manual and device methods by applying a gradually increasing force with the finger or the device, respectively, until a leak was visually observed at the urethral meatus. The device was tested at fast, medium, and slow speeds. A leak sensor was also tested to determine presence of a leak and reaction time of the user. The change in bladder pressure due to the externally applied force (LPP) was the primary outcome. RESULTS There were no significant differences in mean LPP value when compared across experiments (expert, novice), method (manual, device), or speeds. The pooled variance of LPP was significantly decreased (P < 0.05) compared to the manual method when using the device at medium speed; however the slower speed showed no further improvement over the medium speed. The wet sensor detected leaks 385 +/- 187 msec earlier than users' reaction. CONCLUSIONS Use of the device can decrease variability of the experiment but does not alter mean values. Reaction time, inherent in both the manual and device methods, has the potential for a significant impact on LPP outcomes.
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Affiliation(s)
- Andrew J Shoffstall
- Department of Biomedical Engineering, Cleveland Clinic, Cleveland, OH 44195, USA
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