1
|
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.
Collapse
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
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Verma N, Mudge JD, Kasole M, Chen RC, Blanz SL, Trevathan JK, Lovett EG, Williams JC, Ludwig KA. Auricular Vagus Neuromodulation-A Systematic Review on Quality of Evidence and Clinical Effects. Front Neurosci 2021; 15:664740. [PMID: 33994937 PMCID: PMC8120162 DOI: 10.3389/fnins.2021.664740] [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] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Accepted: 03/25/2021] [Indexed: 12/13/2022] Open
Abstract
Background: The auricular branch of the vagus nerve runs superficially, which makes it a favorable target for non-invasive stimulation techniques to modulate vagal activity. For this reason, there have been many early-stage clinical trials on a diverse range of conditions. These trials often report conflicting results for the same indication. Methods: Using the Cochrane Risk of Bias tool we conducted a systematic review of auricular vagus nerve stimulation (aVNS) randomized controlled trials (RCTs) to identify the factors that led to these conflicting results. The majority of aVNS studies were assessed as having "some" or "high" risk of bias, which makes it difficult to interpret their results in a broader context. Results: There is evidence of a modest decrease in heart rate during higher stimulation dosages, sometimes at above the level of sensory discomfort. Findings on heart rate variability conflict between studies and are hindered by trial design, including inappropriate washout periods, and multiple methods used to quantify heart rate variability. There is early-stage evidence to suggest aVNS may reduce circulating levels and endotoxin-induced levels of inflammatory markers. Studies on epilepsy reached primary endpoints similar to previous RCTs testing implantable vagus nerve stimulation therapy. Preliminary evidence shows that aVNS ameliorated pathological pain but not evoked pain. Discussion: Based on results of the Cochrane analysis we list common improvements for the reporting of results, which can be implemented immediately to improve the quality of evidence. In the long term, existing data from aVNS studies and salient lessons from drug development highlight the need for direct measures of local neural target engagement. Direct measures of neural activity around the electrode will provide data for the optimization of electrode design, placement, and stimulation waveform parameters to improve on-target engagement and minimize off-target activation. Furthermore, direct measures of target engagement, along with consistent evaluation of blinding success, must be used to improve the design of controls-a major source of concern identified in the Cochrane analysis. The need for direct measures of neural target engagement and consistent evaluation of blinding success is applicable to the development of other paresthesia-inducing neuromodulation therapies and their control designs.
Collapse
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
| | - Jonah D. Mudge
- Department of Biomedical Engineering, University of Wisconsin – Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe) – Madison, Madison, WI, United States
| | - Maïsha Kasole
- Department of Biomedical Engineering, University of Wisconsin – Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe) – Madison, Madison, WI, United States
| | - Rex C. Chen
- Department of Biomedical Engineering, University of Wisconsin – Madison, Madison, WI, United States
- Wisconsin Institute for Translational Neuroengineering (WITNe) – Madison, Madison, WI, United States
| | - Stephan L. Blanz
- 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
| | | | - Justin C. Williams
- 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
| | - 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
| |
Collapse
|