Management of stimulation safety limits in a neurostimulation system

• US 9,974,960 B2
• Filed: 07/17/2017
• Issued: 05/22/2018
• Est. Priority Date: 04/04/2013
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Steinke, Gustav Karl, Moffitt, Michael A.
• Primary Examiner(s): Johnson, Nicole F
• Application Number:
  US15/651,578
• Publication Number:
  US 20170312526A1
• Time in Patent Office: 309 Days
• Field of Search: 607 59
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/36146 specified by the stimulation parameters
• CPC Class Codes: A61N 1/37235 Aspects of the external programmer

Abstract

An electrical stimulation system for use with a plurality of electrodes implanted within a tissue region comprises a neurostimulator configured for delivering electrical stimulation energy to the plurality of electrodes in accordance with a set of stimulation parameters, thereby injecting a charge into the tissue region, a control device configured for receiving user input to modify the set of stimulation parameters, and controller/processor circuitry configured for, in response to the user input computing a charge injection metric value as a function of a physical electrode parameter and an electrical source parameter for a first set of the electrodes, wherein the electrode set comprises at least two electrodes, comparing the computed charge injection metric value to a safety threshold value, and performing a corrective action based on the comparison.

Claims

1. An implantable pulse generator for use with a plurality of electrodes implanted within a tissue region, comprising:

controller/processor circuitry configured for;

computing, for a set of stimulation parameters, a charge injection metric value as a function of a physical electrode parameter and an electrical source parameter for a first set of at least two of the electrodes;

comparing the computed charge injection metric value to a safety threshold value; and

performing a corrective action based on the comparison.

2. The implantable pulse generator of claim 1, wherein the function comprises independent contributions of the physical electrode parameter and the electrode source parameter for each electrode in the first set.

3. The implantable pulse generator of claim 1, wherein performing the corrective action comprises preventing delivery of electrical stimulation energy to the plurality of electrodes using the set of stimulation parameters.

4. The implantable pulse generator of claim 1, wherein performing the corrective action comprises delivering electrical stimulation energy to the plurality of electrodes in accordance with a different set of stimulation parameters.

5. The implantable pulse generator of claim 1, wherein performing the corrective action comprises conveying a warning signal to a user.

6. The implantable pulse generator of claim 1, wherein the physical electrode parameter is at least one of an electrode surface area, an electrode surface shape, and an electrode material.

7. The implantable pulse generator of claim 1, wherein the electrical source parameter is at least one of a current, a voltage, a charge, charge density, and an impedance.

8. The implantable pulse generator of claim 1, wherein the physical electrode parameter is an electrode surface area, and the electrical source parameter is a charge.

9. The implantable pulse generator of claim 1, wherein physical electrode parameter is an electrode surface area, and the electrical source parameter is a charge and the charge injection metric value is computed in accordance with an equation

10. The implantable pulse generator of claim 1, wherein physical electrode parameter is an electrode surface area, and the electrical source parameter is a charge and the charge injection metric value is computed in accordance with an equation

11. The implantable pulse generator of claim 10, wherein the weighting value is a binary value.

12. The in pulse generator of claim 10, wherein the weighting value is a graduated value.

13. The implantable pulse generator of claim 10, wherein the controller/processor circuitry is configured for determining the weighting value for each electrode in the first set based on an adjacency of the respective electrode relative to a reference electrode in the first set.

14. The implantable pulse generator of claim 10, the controller/processor circuitry is configured for determining the weighting value for each electrode in the first set based on a polarity of the respective electrode.

15. The implantable pulse generator of claim 1, further comprising memory storing a plurality of different safety threshold values.

16. The implantable pulse generator of claim 15, wherein the controller/processor circuitry is configured to select the safety threshold value from the different safety threshold values.

17. The implantable pulse generator of claim 16, wherein the controller/processor circuitry is configured for selecting the safety threshold value from the different safety threshold values based on a characteristic shared by the first set of the at least two of the electrodes.

18. The implantable pulse generator of claim 17, wherein the characteristic shared by the first set is either the same frequency or the same polarity.

19. The implantable pulse generator of claim 1, wherein ratios between injected charge and electrode surface area for at least two of the electrodes of the first set are different.

20. The implantable pulse generator of claim 5, wherein the warning signal is at least one of a visual signal, an aural signal, a vibratory signal, or a modulated neurostimulation signal.