NEUROSTIMULATION SYSTEM FOR PREVENTING MAGNETICALLY INDUCED CURRENTS IN ELECTRONIC CIRCUITRY

• US 20130245723A1
• Filed: 03/13/2013
• Published: 09/19/2013
• Est. Priority Date: 03/16/2012
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Marnfeldt, Goran N., Parramon, Jordi, Murtonen, Salomo, Feldman, Emanuel, Gururaj, Kiran, Weerakoon, Pujitha
• Granted Patent: US 9,220,901 B2
• Time in Patent Office: Days
• US Class Current: 607/62
• CPC Class Codes: A61N 1/086 Magnetic resonance imaging [MRI] compatible leads
• CPC Class Codes: A61N 1/3605 Implantable neurostimulators for stimulating central or peripheral nerve system
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/3718 Monitoring of or protection against external electromagnetic fields or currents

Abstract

A neurostimulation device capable of being placed between an active stimulation state and an inactive stimulation state and method of using same. The neurostimulation device comprises a plurality of electrical terminals configured for being respectively coupled to a plurality of stimulation electrodes, a first solid-state switching device coupled to a first one of the electrical terminals, a variable power source coupled to the first switching device, and a controller configured for, when the neurostimulation device is in the inactive stimulation state, prompting the variable power source to selectively output a relatively low voltage to place the first switching device into a first open state and a relatively high voltage to place the first switching device into a second open state.

Claims

1. A neurostimulation device capable of being placed between an active stimulation state and an inactive stimulation state, comprising:

a plurality of electrical terminals configured for being respectively coupled to a plurality of stimulation electrodes;

a first solid-state switching device coupled to a first one of the electrical terminals;

a variable power source coupled to the first switching device; and

a controller configured for, when the neurostimulation device is in the inactive stimulation state, prompting the variable power source to selectively output a relatively low voltage to place the first switching device into a first open state and a relatively high voltage to place the first switching device into a second open state.

2. The neurostimulation device of claim 1, wherein the controller is further configured for prompting the variable power source to output the relatively high voltage to place the first switching device into the second open state when the neurostimulation is in the active stimulation state.

3. The neurostimulation device of claim 1, further comprising a second solid-state switching device coupled to a second one of the electrical terminals, wherein the first and second switching devices are shorted to each other, wherein the variable power source is coupled to the second switching device, and the controller is configured for, when the neurostimulation device is in the inactive stimulation state, prompting the variable power source to selectively output the relatively low voltage to place the second switching device into the first open state and the relatively high voltage to place the second switching device into the second open state.

4. The neurostimulation device of claim 3, wherein each of the first and second switching devices comprises two complementary transmission gate switches.

5. The neurostimulation device of claim 4, wherein the two complementary transmission gate switches comprises an N-channel metal-oxide semiconductor (NMOS) transistor and a P-channel metal-oxide semiconductor (PMOS).

6. The neurostimulation device of claim 2, further comprising at least one stimulation source, wherein the controller is configured for prompting the at least one stimulation source to convey a series of stimulation pulses between the first and second electrical terminals when the neurostimulation device is in the active stimulation state, and for prompting the variable power source to output the relatively high voltage during the conveyance of each of the pulses, and to ground the first switch after the conveyance of each of the pulses to place the first switching device into a closed state.

7. The neurostimulation device of claim 1, wherein the relatively low voltage is less than five volts, and the relatively high voltage is greater than ten volts.

8. The neurostimulation device of claim 1, further comprising telemetry circuitry configured for receiving a signal external to the neurostimulation device, wherein the controller is configured for prompting the variable power source to output the relatively high voltage in response to the external signal.

9. The neurostimulation device of claim 8, further comprising a sensing mechanism configured for deactivating the neurostimulation device in the presence of an external magnetic field, wherein the controller, in response to the external signal, is configured for preventing the neurostimulation device from being deactivated.

10. The neurostimulation device of claim 9, wherein the controller is configured for preventing the neurostimulation device from being deactivated by disabling the sensing mechanism.

11. The neurostimulation device of claim 1, wherein the variable power supply comprises a battery configured for outputting the relatively low voltage, and a high voltage circuit configured for outputting the relatively high voltage.

12. A method of preventing induced electrical current in a neurostimulation device associated with a patient exposed to external energy, the neurostimulation device including a first solid-state switching device coupled to a first stimulation electrode via a first electrical terminal, the method comprising:

placing the neurostimulation device in an inactive stimulation state;

applying a relatively low voltage to the first switching device when the neurostimulation device is in the inactive stimulation state, thereby placing the first switching device in a first open state;

applying a relatively high voltage to the second switching device when the neurostimulation device is in the inactive stimulation state, thereby placing the first switching device in a second open state;

applying the external energy to the patient, thereby inducing a voltage on the first electrical terminal, wherein the induced voltage is at a level that is prevented from conducting current through the first switching device when in the second open state that would otherwise be conducted through the first switching device when in the first open state.

13. The method of claim 12, wherein the external energy is magnetic energy.

14. The method of claim 12, wherein the magnetic energy is a gradient magnetic field generated by a magnetic resonance imaging (MRI) scanner.

15. The method of claim 12, wherein the first stimulating electrode is carried by a stimulation lead coupled to the neurostimulation device.

16. The method of claim 12, wherein the neurostimulation device includes a second solid-state switching device coupled to a second stimulation electrode via a second electrical terminal, the method further comprising:

applying the relatively low voltage to the second switching device when the neurostimulation device is in the inactive stimulation state, thereby placing the second switching device in a first open state;

applying the relatively high voltage to the second switching device when the neurostimulation device is in the inactive stimulation state, thereby placing the second switching device in a second open state;

applying the external energy to the patient, thereby inducing a voltage on the second electrical terminal, wherein the induced voltage is at a level that is prevented from conducting current through the second switching device when in the second open state that would otherwise be conducted through the second switching device when in the first open state.

17. The method of claim 16, further comprising conveying a series of stimulation pulses between the first and second electrode via the first and second electrical terminals, thereby creating a charge in tissue adjacent the first electrode, wherein the relatively high voltage is applied to the first and second switching devices during the conveyance of each of the pulses, and the first and second switching devices are grounded to place the first and second switching devices into a closed state after the conveyance of each of the pulses, thereby recovering the charge from the tissue.

18. The method of claim 12, wherein the relatively low voltage is less than five volts, and the relatively high voltage is greater than ten volts.

19. The method of claim 12, further comprising transmitting a signal to the neurostimulation device when the neurostimulation device is in the inactive stimulation state, wherein the relatively high voltage is applied to the first switching device in response to the transmitted signal.

20. The method of claim 19, further comprising, in response to the signal, preventing the neurostimulation device from being deactivated in the presence of the external energy.

21. The method of claim 20, wherein the neurostimulation device includes a sensing mechanism configured for deactivating the neurostimulation device in the presence of the external energy, wherein the neurostimulation device is prevented from being deactivated by disabling the sensing mechanism.

22. The method of claim 12, wherein the neurostimulation device is implanted within the patient.