Low impedance implantable extension for a neurological electrical stimulator

• US 20030014080A1
• Filed: 06/28/2001
• Published: 01/16/2003
• Est. Priority Date: 06/28/2001
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Baudino, Michael D.
• Granted Patent: US 6,671,544 B2
• Time in Patent Office: Days
• US Class Current: 607/2
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/36067 Movement disorders, e.g. tremor or Parkinson disease stimulating motor muscle A61N1/36003
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/3752 Details of casing-lead connections
• CPC Class Codes: A61N 1/378 Electrical supply

Abstract

A medical device known as an implantable neurostimulation system is configured for implanting in humans to deliver a therapeutic electrical stimulation to tissue to treat a variety of medical conditions such as pain, movement disorders, pelvic floor disorders, and many other conditions. The implantable neurostimulation has a housing, a power supply carried in the housing, stimulation electronics coupled to the battery and coupled to a neurostimulator connector block, a stimulation lead, and a lead extension. The lead extension is electrically coupleable between the neurostimulation connector block and the stimulation lead. The extension conductor is composed of an outer surface and an inner core. The outer surface has an outer impedance and the inner core has a core impedance that is substantially lower than the outer impedance. Many embodiments of the low impedance lead extension are possible.

Claims

1. An implantable neurological stimulation system having a low impedance extension, comprising:

an implantable neurostimulator including,

a housing,

a power supply carried in the housing,

stimulation electronics coupled to the power supply and coupled to a connector block, and,

a stimulation lead having a lead proximal end, a lead distal end and a lead body, the lead proximal end having at least one electrical contact and the lead distal end having at least one stimulation electrode, at least one lead conductor contained in the lead body electrically connecting the lead electrical contact and to the stimulation electrode;

a lead extension having an extension proximal end, an extension distal end and an extension body, the extension proximal end having at least one proximal contact coupleable to the implantable neurostimulator connector block and an extension distal end having at least one extension distal contact coupleable to the lead proximal contact, at least one extension conductor contained in the extension body electrically connecting the extension distal contact with the extension proximal contact,

wherein the extension conductor is composed of an outer surface and an inner core, the outer surface having an outer impedance and the inner core having a core impedance that is substantially lower than the outer impedance.

2. The implantable neurological stimulation system as in claim 1 wherein the outer surface provides the mechanical properties of the extension conductor.

3. The implantable neurological stimulation system as in claim 2 wherein the mechanical properties include corrosion resistance and fatigue life.

4. The implantable neurological stimulation system as in claim 1 wherein the outer surface is stainless steel.

5. The implantable neurological stimulation system as in claim 1 wherein the outer surface is composed of a nickel, cobalt, chrome, molybdenum alloy.

6. The implantable neurological stimulation system as in claim 1 wherein the outer surface has a resistivity of greater than about 25 micro ohm-centimeter.

7. The implantable neurological stimulation system as in claim 1 wherein the inner core is a silver.

8. The implantable neurological stimulation system as in claim 1 wherein the inner core is a silver alloy.

9. The implantable neurological stimulation system as in claim 1 wherein the inner core is a base material selected from the group consisting of gold, copper, platinum, iridium, tantalum, and aluminum.

10. The implantable neurological stimulation system as in claim 1 wherein the inner core has a resistivity of less than about 12.5 micro ohm-centimeter.

11. The implantable neurological stimulation system as in claim 1 wherein resistivity ratio of the outer surface to the inner core is at least about 2:

1.

12. The implantable low impedance extension of claim 1, wherein the extension conductor resistance is in the range from about 0.05 to about 0.3 ohms per centimeter.

13. The implantable neurological stimulation system as in claim 1 wherein the extension conductor is constructed of drawn filled tubing.

14. The implantable neurological stimulation system as in claim 1 wherein the extension conductor is constructed of more than one wire strand.

15. The implantable neurological stimulation system as in claim 1 wherein the extension conductor has an outer insulator surrounding the outer surface of the extension conductor.

16. The implantable neurological stimulation system as in claim 15 wherein the outer insulator selected from the group consisting of a fluoropolymer, polyurethane, silicone, and polyimide.

17. The implantable neurological stimulation system as in claim 1 wherein at least one extension conductor is configured as at least one coil in at least one lumen.

18. The implantable neurological stimulation system as in claim 1 wherein there is at least one filar in the coil and at least one lumen in the extension body.

19. The implantable neurological stimulation system as in claim 1 wherein at least one extension conductor has an outer insulator and the extension conductor is formed into a coil contained in at least one lumen in the extension body.

20. The implantable neurological stimulation system as in claim 1 wherein at least one extension conductor is configured as at least one linear wire in at least one lumen.

21. The implantable neurological stimulation system as in claim 20 wherein the at least one linear wire has more than one wire strand.

22. The implantable neurological stimulation system as in claim 20 wherein the at least one linear wire has an outer insulator.

25. The implantable neurological stimulation system as in claim 24 wherein the outer surface provides the mechanical properties of the extension conductor.

26. The implantable neurological stimulation system as in claim 25 wherein the mechanical properties include corrosion resistance and fatigue life.

27. The implantable neurological stimulation system as in claim 24 wherein the outer surface is stainless steel.

28. The implantable neurological stimulation system as in claim 24 wherein the outer surface is composed of a nickel, cobalt, chrome, molybdenum alloy.

29. The implantable neurological stimulation system as in claim 24 wherein the outer surface has a resistivity of greater than about 25 micro ohm-centimeter.

30. The implantable neurological stimulation system as in claim 24 wherein the inner core is a silver.

31. The implantable neurological stimulation system as in claim 24 wherein the inner core is a silver alloy.

32. The implantable neurological stimulation system as in claim 24 wherein the inner core is a base material selected from the group consisting of gold, copper, platinum, iridium, tantalum, and aluminum.

33. The implantable neurological stimulation system as in claim 24 wherein the inner core has a resistivity of less than about 12.5 micro ohm-centimeter.

34. The implantable neurological stimulation system as in claim 24 wherein resistivity ratio of the outer surface to the inner core is at least about 2:

1.

35. The implantable low impedance extension of claim 24, wherein the extension conductor resistance is in the range from about 0.05 to about 0.3 ohms per centimeter.

36. The implantable neurological stimulation system as in claim 24 wherein the extension conductor is constructed of drawn filled tubing.

37. The implantable neurological stimulation system as in claim 24 wherein the extension conductor is constructed of more than one wire strand.

38. The implantable neurological stimulation system as in claim 24 wherein the extension conductor has an outer insulator surrounding the outer surface of the extension conductor.

39. The implantable neurological stimulation system as in claim 38 wherein the outer insulator selected from the group consisting of a fluoropolymer, polyurethane, silicone, and polyimide.

40. The implantable neurological stimulation system as in claim 24 wherein at least one extension conductor is configured as at least one coil in at least one lumen.

41. The implantable neurological stimulation system as in claim 24 wherein there is at least one filar in the coil and at least one lumen in the extension body.

42. The implantable neurological stimulation system as in claim 24 wherein at least one extension conductor has an outer insulator and the extension conductor is formed into a coil contained in at least one lumen in the extension body.

43. The implantable neurological stimulation system as in claim 24 wherein at least one extension conductor is configured as at least one linear wire in at least one lumen.

44. The implantable neurological stimulation system as in claim 43 wherein the at least one linear wire has more than one wire strand.

45. The implantable neurological stimulation system as in claim 43 wherein the at least one linear wire has an outer insulator.

48. The low impedance conductor as in claim 47 wherein the outer surface provides the mechanical properties of the extension conductor.

49. The low impedance conductor as in claim 48 wherein the mechanical properties include corrosion resistance and fatigue life.

50. The low impedance conductor as in claim 47 wherein the outer surface is stainless steel.

51. The low impedance conductor as in claim 47 wherein the outer surface is composed of an nickel, cobalt, chrome, molybdenum alloy.

52. The low impedance conductor as in claim 47 wherein the outer surface has a resistivity of greater than about 25 micro ohm-centimeter.

53. The low impedance conductor as in claim 47 wherein the inner core is a silver.

54. The low impedance conductor as in claim 47 wherein the inner core is a silver alloy.

55. The low impedance conductor as in claim 47 wherein the inner core is a base material selected from the group consisting of gold, copper, platinum, iridium, tantalum, and aluminum.

56. The low impedance conductor as in claim 47 wherein the inner core has a resistivity of less than about 12.5 micro ohm-centimeter.

57. The low impedance conductor as in claim 47 wherein resistivity ratio of the outer surface to the inner core is at least about 2:

1.

58. The low impedance conductor of claim 47 wherein the extension conductor resistance is in the range from about 0.05 to about 0.3 ohms per centimeter.

59. The low impedance conductor as in claim 47 wherein the extension conductor is constructed of drawn filled tubing.

60. The low impedance conductor as in claim 47 wherein the extension conductor is constructed of more than one wire strand.

61. The low impedance conductor as in claim 47 wherein the extension conductor has an outer insulator surrounding the outer surface of the extension conductor.

62. The low impedance conductor as in claim 61 wherein the outer insulator selected from the group consisting of a fluoropolymer, polyurethane, silicone, and polyimide.

23. An implantable neurological stimulation system having a low impedance extension, comprising:

an implantable neurostimulator including,

a housing,

a power supply carried in the housing,

stimulation electronics coupled to the power supply and coupled to a connector block, and,

a stimulation lead having a lead proximal end, a lead distal end and a lead body, the lead proximal end having at least one electrical contact and the lead distal end having at least one stimulation electrode, at least one lead conductor contained in the lead body electrically connecting the lead electrical contact and to the stimulation electrode;

means for lead extension coupleable between the implantable neurostimulator connector block and the lead proximal contact to electrically connect the implantable neurostimulator to the stimulation electrode using an extension conductor that has an outer surface selected for mechanical properties and an inner core selected for electrical conductivity that has an impedance substantially less than the outer surface.

24. A low impedance extension for an implantable neurological stimulation system, comprising:

an extension proximal end, an extension distal end and an extension body, the extension proximal end having at least one proximal contact coupleable to an implantable neurostimulator connector block and an extension distal end having at least one extension distal contact coupleable to the lead proximal contact;

at least one extension conductor contained in the extension body electrically connecting the extension distal contact with the extension proximal contact,

wherein the extension conductor is composed of an outer surface and an inner core, the outer surface having an outer impedance and the inner core having a core impedance that is substantially lower than the outer impedance.

46. A low impedance extension for an implantable neurological stimulation system, comprising:

an extension proximal end, an extension distal end and an extension body, the extension proximal end having at least one proximal contact coupleable to an implantable neurostimulator connector block and an extension distal end having at least one extension distal contact coupleable to the lead proximal contact;

means for extension electrical conduction that has an outer surface selected for mechanical properties and an inner core selected for electrical conductivity that has an impedance substantially less than the outer surface.

47. A low impedance conductor for a low impedance extension, comprising:

an outer surface selected for mechanical properties of flexibility and electrical connections having an outer impedance; and

,

an inner core selected for conductivity having a core impedance that is substantially lower than the outer impedance.

63. A low impedance conductor for a low impedance extension, comprising:

means for outer surface selected for mechanical properties of flexibility and electrical connections having an outer impedance; and

,

means for inner core selected for conductivity having a core impedance that is substantially lower than the outer impedance.