STEERING STIMULATION CURRENT BY EMPLOYING STEERING CURRENT

• US 20110077717A1
• Filed: 09/10/2010
• Published: 03/31/2011
• Est. Priority Date: 09/29/2009
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Poletto, Christopher J.
• Granted Patent: US 8,452,414 B2
• Time in Patent Office: Days
• US Class Current: 607/60
• CPC Class Codes: A61N 1/0553 Paddle shaped electrodes, e.g. for laminotomy
• CPC Class Codes: A61N 1/3616 Voltage density or current density
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration

Abstract

Stimulation current is steered further outward and/or inward from a plane of the stimulating electrodes by using one or more steering currents. The steering current may be used to occupy space in the tissue where stimulation is not desired and to force the stimulation current to pass through target tissue. The steering current may be present in various locations such as in tissue that is immediately adjacent the plane of the electrodes to force the stimulation current away from the immediately adjacent area and deeper into surrounding target tissue. The steering current may be present in tissue that is beyond the target tissue to confine the outward reach of the stimulation current to that target tissue. The stimulation current may be produced by one power source while the steering current may be produced by one or more other power sources, each of the power sources being unreferenced to each other.

Claims

1. A method of steering current to stimulate tissue, comprising:

generating a first current through tissue and between a first electrode and a second electrode, the first electrode and second electrode being referenced to a first voltage source; and

while generating the first current, generating a second current through tissue and between a third electrode and a fourth electrode, the third electrode and the fourth electrode being referenced to a second voltage source that is not referenced to the first voltage source, the first and second electrodes being positioned between the third and fourth electrodes.

2. The method of claim 1, wherein the first current is a stimulation current and the second current is a steering current that limits an outward reach of the stimulation current.

3. The method of claim 2, wherein the stimulation current is a train of pulses and the steering current is a squarewave.

4. The method of claim 2, wherein the steering current is present only when the stimulation current is present.

5. The method of claim 2, wherein the first and second electrodes present on a paddle, are rectangular, and have a first length and the third and fourth electrodes are present on the paddle, are rectangular, and have a second length that is more than twice the first length.

6. The method of claim 2, further comprising:

while generating the first and second currents, generating a third current through tissue and between a fifth electrode and a sixth electrode, the fifth electrode and the sixth electrode being referenced to a third voltage source that is not referenced to the first and second voltage sources, the fifth and sixth electrodes being located between the first, second, third, and fourth electrodes, the third current being a second steering current that increases an outward reach of the stimulation current.

7. The method of claim 6, wherein the steering current and the second steering current have a frequency that is greater than a frequency of the stimulation current such that the steering current and the second steering current do not depolarize the tissue.

8. The method of claim 2, wherein the steering current has a frequency that is greater than a frequency of the stimulation current such that the steering current does not depolarize the tissue.

9. The method of claim 1, wherein the second current is a stimulation current and the first current is a steering current that increases an outward reach of the stimulation current.

10. The method of claim 9, wherein the stimulation current is a train of pulses and the steering current is a squarewave.

11. The method of claim 9, wherein the steering current is present only when the stimulation current is present.

12. The method of claim 9, wherein the first and second electrodes are rectangular and have a first length and the third and fourth electrodes are rectangular and have a second length that is less than half of the first length.

13. The method of claim 9, further comprising:

while generating the first and second currents, generating a third current through tissue and between a fifth electrode and a sixth electrode, the fifth electrode and the sixth electrode being referenced to a third voltage source that is not referenced to the first and second voltage sources, the first, second, third, and fourth electrodes being located between the fifth and sixth electrodes, the third current being a second steering current that limits an outward reach of the stimulation current.

14. The method of claim 13, wherein the steering current and the second steering current have a frequency that is greater than a frequency of the stimulation current such that the steering current and the second steering current do not depolarize the tissue.

15. The method of claim 9, wherein the steering current has a frequency that is greater than a frequency of the stimulation current such that the steering current does not depolarize the tissue.

16. The method of claim 1, wherein the first, second, third, and fourth electrodes are concentric circles, with the third electrode having a smallest diameter and the fourth electrode having a largest diameter.

17. The method of claim 1, wherein the first, second, third and fourth electrodes are ring electrodes along a lead body.

18. An implantable medical device, comprising:

a first voltage source;

a second voltage source not referenced to the first voltage source;

a first and a second electrical connector referenced to the first voltage source such that a first current from the first voltage source flows between the first and second electrical connectors; and

a third and a fourth electrical connector referenced to the second voltage source such that a second current from the second voltage source flows between the third and fourth electrical connectors.

19. The implantable medical device of claim 18, further comprising at least one electrical lead that comprises:

a first electrode electrically coupled to the first electrical connector;

a second electrode electrically coupled to the second electrical connector;

a third electrode electrically coupled to the third electrical connector; and

a fourth electrode electrically coupled to the fourth electrical connector, wherein the first and second electrodes are located between the third and fourth electrodes.

20. The implantable medical device of claim 19, wherein the first current is a stimulation current and the second current is a steering current that limits an outward reach of the stimulation current.

21. The implantable medical device of claim 20, wherein the stimulation current is a train of pulses and the steering current is a squarewave.

22. The implantable medical device of claim 20, wherein the steering current is present only when the stimulation current is present.

23. The implantable medical device of claim 20, wherein the first and second electrodes are present on a paddle, are rectangular, and have a first length and the third and fourth electrodes are present on the paddle, are rectangular, and have a second length that is more than twice the first length.

24. The implantable medical device of claim 20, further comprising:

a third voltage source not referenced to the first and second voltage sources;

a fifth and a sixth electrical connector referenced to the third voltage source such that a third current from the third voltage source flows between the fifth and sixth electrical connectors.

25. The implantable medical device of claim 24, wherein the lead further comprises:

a fifth electrode electrically coupled to the fifth electrical connector; and

a sixth electrode electrically coupled to the sixth electrical connector, the fifth and sixth electrodes being located between the first, second, third, and fourth electrodes, the third current being a second steering current that increases an outward reach of the stimulation current.

26. The implantable medical device of claim 25, wherein the steering current and the second steering current have a frequency that is greater than a frequency of the stimulation current such that the steering current and the second steering current do not depolarize the tissue.

27. The implantable medical device of claim 20, wherein the steering current has a frequency that is greater than a frequency of the stimulation current such that the steering current does not depolarize the tissue.

28. The implantable medical device of claim 19, wherein the second current is a stimulation current and the first current is a steering current that increases an outward reach of the stimulation current.

29. The implantable medical device of claim 28, wherein the stimulation current is a train of pulses and the steering current is a squarewave.

30. The implantable medical device of claim 28, wherein the steering current is present only when the stimulation current is present.

31. The implantable medical device of claim 28, wherein the first and second electrodes are rectangular and have a first length and the third and fourth electrodes are rectangular and have a second length that is less than half of the first length.

32. The implantable medical device of claim 28, further comprising:

a third voltage source not referenced to the first and second voltage sources;

a fifth and a sixth electrical connector referenced to the third voltage source such that a third current from the third voltage source flows between the fifth and sixth electrical connectors.

33. The implantable medical device of claim 32, wherein the lead further comprises:

a fifth electrode electrically coupled to the fifth electrical connector; and

a sixth electrode electrically coupled to the sixth electrical connector, the first, second, third, and fourth electrodes being located between the fifth and sixth electrodes, the third current being a second steering current that limits an outward reach of the stimulation current.

34. The implantable medical device of claim 33, wherein the steering current and the second steering current have a frequency that is greater than a frequency of the stimulation current such that the steering current and the second steering current do not depolarize the tissue.

35. The implantable medical device of claim 28, wherein the steering current has a frequency that is greater than a frequency of the stimulation current such that the steering current does not depolarize the tissue.

36. The implantable medical device of claim 19, wherein the first, second, third, and fourth electrodes are concentric circles, with the third electrode having a smallest diameter and the fourth electrode having the largest diameter.

37. The implantable medical device of claim 19, wherein the first, second, third and fourth electrodes are ring electrodes along a body of the lead.

38. A method of providing stimulation therapy, comprising:

sending programming from an external device to an implantable medical device, the programming specifying stimulation parameters and steering current parameters;

while stimulation signals are being output from a first power source of the implantable medical device to leads coupled to the implantable medical device in accordance with the stimulation parameters, outputting at least one steering current from a second power source of the implantable medical device that is unreferenced to the first power source in accordance with the steering current parameters.

39. A system of providing stimulation therapy, comprising:

an external device that sends programming that specifies stimulation parameters and steering current parameters;

an implantable medical device that receives the programming and outputs stimulation signals from a first power source according to the stimulation parameters, and while outputting the stimulation signals from the first power source, outputs at least one steering current from a second power source that is unreferenced to the first power source in accordance with the steering current parameters.