METHOD AND APPARATUS FOR DIRECTED PROPAGATION OF NEURAL STIMULATION

• US 20150202433A1
• Filed: 01/14/2015
• Published: 07/23/2015
• Est. Priority Date: 01/17/2014
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Franke, Manfred, Ternes, David J., Hincapie Ordonez, Juan Gabriel, Ruble, Stephen B., Hamann, Jason J., Mohsenian, Kevin J., Gordon, Jack
• Granted Patent: US 10,434,303 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0556 Cuff electrodes
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/36114 Cardiac control, e.g. by vagal stimulation stimulating the heart A61N1/362

Abstract

A neural stimulation system delivers neural stimulation to a target nerve with control of direction of propagation of evoked neural signals in one or more fiber types of the target nerve using electrode configuration, thereby providing effective therapy while minimizing unintended effects. In various embodiments, mechanical parameters of a multi-polar electrode are determined to provide directed propagation of the neural stimulation by effecting neural conduction block in or near the stimulation site. In various embodiments, the electrode includes a cathode for evoking action potentials and a plurality of anodes for blocking the propagation of the evoked action potentials in specified direction(s) and fiber type(s) while minimizing the formation of virtual cathodes.

Claims

1. A system for delivering stimulation to a nerve at a stimulation site, comprising:

an electrode configured to deliver electrical stimulation pulses to the nerve at the stimulation site, the electrode including;

a substrate;

a cathode formed on the cuff substrate, the cathode configured to allow the electrical stimulation pulses to evoke action potentials;

a plurality of anodes formed on the cuff substrate, the plurality of anodes shaped, sized, and arranged to effect neural conduction block without forming a virtual cathode, the neural conduction block including blocking of propagation of the evoked action potentials from the cathode in one or more fiber types of the nerve.

2. The system of claim 1, wherein the electrode comprises a nerve cuff electrode, the substrate comprises a cuff substrate including a self-curling sheet configured to be wrapped around a portion of the nerve at the stimulation site, the cathode and the plurality of anodes comprise one or more ring electrodes each configured to encircle the nerve, and the plurality of anodes are shaped, sized, and arranged to effect the neural conduction block substantially within the portion of the nerve wrapped within the nerve cuff electrode.

3. The system of claim 2, wherein the one or more ring electrodes comprises one or more ring electrodes each including an array of conductive contacts, the array arranged to encircle the portion of the nerve wrapped by the nerve cuff electrode.

4. The system of claim 2, wherein the plurality of anodes comprises a blocking anode and one or more flanking anodes, such that the electrical stimulation pulses each depolarize a membrane of the nerve adjacent to the cathode to evoke the action potentials and hyperpolarize a membrane of the nerve adjacent to the blocking anode to block propagation of the evoked action potentials from the cathode to the blocking anode without forming the virtual cathode.

5. The system of claim 4, wherein the plurality of anodes is shaped, sized, and arranged to allow the electrical stimulation pulses to provide a graded electric field in and around the portion of the nerve wrapped within the nerve cuff electrode.

6. The system of claim 5, wherein the plurality of anodes comprises the blocking electrode and one flanking electrode, and further comprising an impedance circuit coupled between the blocking electrode and the flanking electrode to control distribution of current in the plurality of anodes, the current flowing from the cathode to the plurality of anodes.

7. The system of claim 6, wherein the impedance circuit comprises a resistor incorporated into the nerve cuff electrode.

8. The system of claim 5, wherein the nerve cuff electrode comprises:

a conductive sheet on a portion of the cuff substrate; and

an insulation sheet over the conductive sheet, the insulation sheet including openings exposing portions of the conductive sheets to form the plurality of anodes, the openings including one or more array of openings to form the one or more flanking anodes each including an array of conductive contacts.

9. The system of claim 8, wherein the one or more flanking anodes comprise a first flanking electrode including a first array of first conductive contacts and a second flanking electrode including a second array of second conductive contacts, the first conductive contacts substantially bigger than the second conductive contacts.

10. The system of claim 5, wherein the cuff substrate is configured to be funnel-shaped when being wrapped around the portion of the nerve at the stimulation site, and the nerve cuff electrode comprises:

a conductive sheet on the cuff substrate; and

one or more insulation layers on a portion of the conductive sheet, the one or more insulation layers configured to center the portion of the nerve with respect to the nerve cuff electrode and expose portions of the conductive sheet to form the plurality of anodes, such that each anode of the plurality of anode is separated from the nerve by a distance allowing for controlled ingrowth of connective tissue between the each anode and the nerve when the nerve cuff electrode is wrapped around the portion of the nerve at the stimulation site.

11. The system of claim 5, further comprising:

an implantable neural stimulator including a pulse output circuit configured to deliver the electrical stimulation pulses, the pulse output circuit including one or more independently controllable output channels; and

one or more leads configured to connect the nerve cuff electrode to the implantable neural stimulator, the one or more leads including a cathode conductor and an anode conductor, the cathode conductor configured to provide an electrical connection between the cathode and an output channel of the one or more output channels, the anode conductor configured to provide electrical connections between the plurality of anodes and the output channel of the one or more output channels.

12. A method for delivering stimulation to a nerve at a stimulation site, comprising:

providing a substrate;

forming a cathode and a plurality of anodes on the substrate such that an electrode for delivering electrical stimulation pulses to the nerve at the stimulation site is formed; and

determining shape, size, and arrangement of the cathode and the plurality of anode such that action potentials are evoked in a portion of the nerve adjacent the cathode and neural conduction block is effected without forming a virtual cathode, the neural conduction block including blocking of propagation of the evoked action potentials from the cathode in one or more fiber types.

13. The method of claim 12, wherein the electrode formed comprises an nerve cuff electrode, the substrate comprises a cuff substrate including a self-curling sheet configured to be wrapped around a portion of the nerve at the stimulation site, and determining the shape, size, and arrangement of the cathode and the plurality of anode comprises determining the shape, size, and arrangement of the cathode and the plurality of anode such that action potentials are evoked in the portion of the nerve adjacent the cathode and neural conduction block is effected substantially within the portion of the nerve wrapped within the nerve cuff electrode without forming the virtual cathode.

14. The method of claim 13, wherein forming the cathode and the plurality of anodes comprises forming a blocking anode and one or more flanking anodes in a manner allowing the electrical stimulation pulses to each depolarize a membrane of the nerve at the cathode to evoke the action potentials and hyperpolarize a membrane of the nerve at the blocking anode to block propagation of the evoked action potentials from the cathode to the blocking anode without forming the virtual cathode.

15. The method of claim 14, wherein forming the cathode and the plurality of anodes comprises forming the plurality of anode in a manner allowing the electrical stimulation pulses to provide a graded electric field in and around the portion of the nerve wrapped within the nerve cuff electrode.

16. The method of claim 15, comprising controlling distribution of current in the plurality of anodes using an impedance coupled between two anodes of the plurality of anodes, the current flowing from the cathode to the plurality of anodes.

17. The method of claim 15, wherein forming the cathode and the plurality of anodes comprises:

affixing a conductive sheet on a portion of the cuff substrate; and

affixing an insulation sheet over the conductive sheet, the insulation sheet including openings exposing portions of the conductive sheets to form the plurality of anodes, the openings including one or more array of openings to form the one or more flanking anodes each including an array of conductive contacts.

18. The method of claim 15, wherein forming the cathode and the plurality of anodes comprises:

affixing a conductive sheet on the cuff substrate; and

affixing one or more insulation bands on a portion of the conductive sheet, the one or more insulation bands configured to center the portion of the nerve with respect to the nerve cuff electrode and expose portions of the conductive sheet to form the plurality of anodes, such that each anode of the plurality of anode is separated from the nerve by a distance allowing for controlled ingrowth of connective tissue between the each anode and the nerve when the nerve cuff electrode is wrapped around the portion of the nerve at the stimulation site.

19. The method of claim 14, comprising:

providing an initial amount of blocking current to the blocking anode, the blocking current flowing from the cathode to the blocking anode;

providing an initial amount of flanking current to each flanking anode of the one or more flanking electrodes, the flanking current flowing from the cathode to the each flanking anode;

increasing one or more of the blocking current and the flanking current in response to the neural conduction block not being satisfactorily effected; and

decreasing one or more of the blocking current and the flanking current in response to the neural conduction block being satisfactorily effected.

20. The method of claim 14, wherein determining the shape, size, and arrangement of the cathode and the plurality of anode comprises:

providing an initial amount of blocking current to the blocking anode, the blocking current flowing from the cathode to the blocking anode;

providing an initial amount of flanking current to each flanking anode of the one or more flanking electrodes, the flanking current flowing from the cathode to the each flanking anode; and

adjusting geometrical parameters of the cathode and the plurality of anode in response to the neural conduction block not being satisfactorily effected.