CHARGE RECOVERY BI-PHASIC CONTROL FOR TISSUE STIMULATION

• US 20110106214A1
• Filed: 11/02/2010
• Published: 05/05/2011
• Est. Priority Date: 11/02/2009
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Carbunaru, Rafael, Bradley, Kerry
• Granted Patent: US 9,415,223 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/36128 Control systems
• CPC Class Codes: A61N 1/36178 Burst or pulse train parameters
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration

Abstract

A method and external control device for providing therapy to a patient using first and second electrodes implanted within the patient is provided. A train of electrical multi-phasic pulses is generated. A first electrical current is sourced from the second electrode and at least a portion of the first electrical current is sunk to the first electrode during a stimulation phase of each multi-phasic pulse, thereby therapeutically stimulating a first tissue region adjacent the first electrode. A second electrical current is sourced from the first electrode and at least a portion of the second electrical current is sunk to the second electrode during a charge recovery phase of each multi-phasic pulse, thereby recovering at least a portion of the charge that had been injected into the patient during the stimulation phase of each multi-phasic pulse, and therapeutically stimulating a second tissue region adjacent the second electrode.

Claims

1. A method of providing therapy to a patient using first and second electrodes implanted within the patient, the method comprising:

generating a train of electrical multi-phasic pulses;

sourcing a first electrical current from the second electrode and sinking at least a portion of the first electrical current to the first electrode during a stimulation phase of each multi-phasic pulse, thereby therapeutically stimulating a first tissue region adjacent the first electrode; and

sourcing a second electrical current from the first electrode and sinking at least a portion of the second electrical current to the second electrode during a charge recovery phase of each multi-phasic pulse, thereby recovering at least a portion of the charge that had been injected into the patient during the stimulation phase of each multi-phasic pulse, and therapeutically stimulating a second tissue region adjacent the second electrode.

2. The method of claim 1, wherein the first electrical current sourced from the second electrode during the stimulation phase of each multi-phasic pulse does not stimulate the second tissue region, and the second electrical current sourced from the first electrode during the charge recovery phase of each multi-phasic pulse does not stimulate the first tissue region.

3. The method of claim 1, wherein the first and second tissue regions are contiguous.

4. The method of claim 1, wherein no electrical current is conveyed between the first electrode and the second electrode during an interphase between the stimulation phase and the charge recovery phase of each multi-phasic pulse.

5. The method of claim 4, wherein the interphase is at least one-half of the stimulation phase.

6. The method of claim 1, wherein each multi-phasic pulse is a bi-phasic pulse.

7. The method of claim 6, wherein each bi-phasic pulse is symmetrical.

8. The method of claim 7, wherein each bi-phasic pulse is asymmetrical.

9. The method of claim 1, further comprising:

sinking another portion of the first electrical current to a third electrode implanted within the patient during the stimulation phase of each multi-phasic pulse, wherein a third tissue region adjacent the third electrode is not stimulated; and

sourcing a third electrical current from the third electrode and sinking at least a portion of the third electrical current to the second electrode during the charge recovery phase of each multi-phasic pulse, thereby, in combination with the at least a portion of the second electrical current sunk to the second electrode, recovering the at least a portion of the charge injected into the patient during the stimulation phase of each multi-phasic pulse, and therapeutically stimulating the second tissue region adjacent the second electrode.

10. The method of claim 1, wherein the first electrode has a first stimulation threshold during the stimulation phase of each multi-phasic pulse, and the second electrode has a second stimulation threshold different from the first stimulation threshold during the charge recovery phase of each multi-phasic pulse.

11. The method of claim 10, wherein electrical current is conveyed between the first and second electrodes during the stimulation and charge recovery phases of each multi-phasic pulse in a manner that prevents excessive stimulation of the first and second target tissue regions.

12. The method of claim 11, further comprising performing at least one of the following steps:

sinking another portion of the first electrical current to a third electrode implanted within the patient during the stimulation phase of each multi-phasic pulse if the first stimulation threshold is less than the second stimulation threshold; and

sinking another portion of the second electrical current to a third electrode implanted within the patient during the charge recovery phase of each multi-phasic pulse if the second stimulation threshold is less than the first stimulation threshold.

13. The method of claim 12, further comprising performing at least one of the following steps:

adjusting the duration of the stimulation phase to be longer than the duration of the charge recovery phase of each multi-phasic pulse if the first stimulation threshold is less than the second stimulation threshold; and

adjusting the duration of the charge recovery phase to be longer than the duration of the stimulation phase of each multi-phasic pulse if the second stimulation threshold is less than the first stimulation threshold.

14. The method of claim 1, wherein each of the first and second tissue regions comprises spinal cord tissue.

15. An external control device for controlling a neurostimulator and associated first and second electrodes implanted within a patient, comprising:

a user interface configured for receiving an input from a user that defines the first and second electrodes as tissue stimulating electrodes;

telemetry circuitry configured for wirelessly communicating with the neurostimulator; and

a processor configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry to generate a train of electrical multi-phasic pulses, source a first electrical current from the second electrode and sink at least a portion of the first electrical current to the first electrode during a stimulation phase of each multi-phasic pulse in a manner that would therapeutically stimulate a first tissue region adjacent the first electrode, and to source a second electrical current from the first electrode and sink at least a portion of the second electrical current to the second electrode during a charge recovery phase of each multi-phasic pulse in a manner that recovers at least a portion of the charge that had been injected into the patient during the stimulation phase of each multi-phasic pulse, and therapeutically stimulates a second tissue region adjacent the second electrode.

16. The external control device of claim 15, wherein the processor is configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry to source the first electrical current from the second electrode during the stimulation phase of each multi-phasic pulse in a manner that does not stimulate the second tissue region, and source the second electrical current from the first electrode during the charge recovery phase of each multi-phasic pulse in a manner that does not stimulate the first tissue region.

17. The external control device of claim 15, wherein the processor is configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry to adjust an interphase between the stimulation phase and the charge recovery phase of each multi-phasic pulse.

18. The external control device of claim 17, wherein the interphase is at least one-half of the stimulation phase.

19. The external control device of claim 15, wherein each multi-phasic pulse is a bi-phasic pulse.

20. The external control device of claim 19, wherein each bi-phasic pulse is symmetrical.

21. The external control device of claim 19, wherein each bi-phasic pulse is asymmetrical.

22. The external control device of claim 15, wherein the processor is configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry to sink another portion of the first electrical current to a third electrode implanted within the patient during the stimulation phase of each multi-phasic pulse in a manner that does not stimulate a third tissue region adjacent the third electrode, and to source a third electrical current from the third electrode and sink at least a portion of the third electrical current to the second electrode during the charge recovery phase of each multi-phasic pulse in a manner that, in combination with the at least a portion of the second electrical current sunk to the second electrode, recovers the at least a portion of the charge injected into the patient during the stimulation phase of each multi-phasic pulse, and therapeutically stimulates the second tissue region adjacent the second electrode.

23. The external control device of claim 15, wherein the processor is configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry to sink a first test electrical current to the first electrode from the first tissue region, and to sink a second test electrical current to the second electrode from the second tissue region, determine a first stimulation threshold of the first electrode based on the first test electrical current, and determine a second stimulation threshold of the second electrode based on the second test electrical current.

24. The external control device of claim 23, wherein the processor is configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry based on the determined first and second stimulation thresholds to convey electrical current between the first and second electrodes during the stimulation and charge recovery phases of each multi-phasic pulse in a manner that prevents excessive stimulation of the first and second target tissue regions.

25. The external control device of claim 24, wherein the processor is configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry to perform at least one of the following steps:

sink another portion of the first electrical current to a third electrode implanted within the patient during the stimulation phase of each multi-phasic pulse if the first stimulation threshold is less than the second stimulation threshold; and

sink another portion of the second electrical current to the third electrode during the charge recovery phase of each multi-phasic pulse if the second stimulation threshold is less than the first stimulation threshold.

26. The external control device of claim 25, wherein the processor is configured for generating and transmitting instructions to the neurostimulator via the telemetry circuitry to perform at least one of the following steps:

adjust the duration of the stimulation phase of each multi-phasic pulse to be longer than the duration of the charge recovery phase of each multi-phasic pulse if the first stimulation threshold is less than the second stimulation threshold; and

adjust the duration of the charge recovery phase of each multi-phasic pulse to be longer than the duration of the stimulation phase of each multi-phasic pulse if the second stimulation threshold is less than the first stimulation threshold.