Method of routing electrical current to bodily tissues via implanted passive conductors

• US 8,406,886 B2
• Filed: 03/09/2009
• Issued: 03/26/2013
• Est. Priority Date: 01/22/2004
• Status: Active Grant

• Current Assignee: 2249020 Alberta Limited
• Original Assignee: Rehabtronics, Inc.
• Inventors: Gaunt, Robert Andrew, Prochazka, Arthur
• Primary Examiner(s): Layno, Carl H
• Assistant Examiner(s): BEHRINGER, LUTHER G
• Application Number:
  US12/400,202
• Publication Number:
  US 20090222053A1
• Time in Patent Office: 1,478 Days
• Field of Search: 607/46, 607/75
• US Class Current: 607/46
• CPC Class Codes: A61B 5/0028 Body tissue as transmission medium, i.e. transmission systems where the medium is the human body
• CPC Class Codes: A61B 5/4029 for evaluating the peripheral nervous systems A61B5/24 takes precedence
• CPC Class Codes: A61B 5/4082 Diagnosing or monitoring movement diseases, e.g. Parkinson, Huntington or Tourette
• CPC Class Codes: A61N 1/0472 Structure-related aspects
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/0504 Subcutaneous electrodes
• CPC Class Codes: A61N 1/0556 Cuff electrodes
• CPC Class Codes: A61N 1/36017 with leads or electrodes penetrating the skin
• CPC Class Codes: A61N 1/36021 for treatment of pain
• CPC Class Codes: A61N 1/36071 Pain

Abstract

The invention provides an implant, system and method for electrically stimulating a target tissue to either activate or block neural impulses. The implant provides a conductive pathway for a portion of electrical current flowing between surface electrodes positioned on the skin and transmits that current to the target tissue. The implant has a passive electrical conductor of sufficient length to extend from subcutaneous tissue located below a surface cathodic electrode to the target tissue. The conductor has a pick-up end which forms an electrical termination having a sufficient surface area to allow a sufficient portion of the electrical current to flow through the conductor, in preference to flowing through body tissue between the surface electrodes, such that the target tissue is stimulated to either activate or block neural impulses. The conductor also has a stimulating end which forms an electrical termination for delivering the current to the target body tissue.

Claims

1. A system, comprising:

a first surface electrode and a second surface electrode configured to make electrical contact with a subject'"'"'s skin and to transmit electrical current to body tissue;

a stimulator electrically coupled to the first surface electrode and the second surface electrode, the stimulator configured to supply electrical current to the first surface electrode and the second surface electrode; and

an implant including a passive electrical conductor having an uninsulated pick-up portion and an uninsulated delivery portion, the uninsulated pick-up portion being configured to pick up at least a portion of the electrical current and to transmit the portion of the electric current through the conductor to a target body tissue, the passive electrical conductor having an insulated body portion between the uninsulated pick-up portion and the uninsulated delivery portion.

2. The system of claim 1, wherein:

the conductor has a length sufficient to extend, once implanted, from subcutaneous tissue located below the first surface electrode to a target body tissue which is to be stimulated.

3. The system of claim 2, wherein:

the uninsulated pick-up portion forms an electrical termination having a sufficient surface area such that, once implanted in subcutaneous tissue below the first surface electrode, the portion of the electrical current flows through the conductor, in preference to flowing through body tissue between the first surface electrode and the second surface electrode, and

the uninsulated delivery portion forms an electrical termination to deliver the portion of the electrical current to the target body tissue, once implanted.

4. The system of claim 3, wherein:

the electrical termination at one or both of the uninsulated pick-up portion and the uninsulated delivery portion is formed from the uninsulated end of the conductor, or from other conductive or capacitive materials; and

the body insulated portion extends from the uninsulated pick-up portion to the uninsulated delivery portion of the conductor.

5. The system of claim 4, wherein:

the stimulator is configured to be external to the subject'"'"'s body and to supply direct, pulsatile, or alternating current to the first surface electrode and the second surface electrode.

6. The system of claim 1, wherein at least one of the uninsulated pick-up portion or the uninsulated delivery portion is configured to include an enlarged surface area in the form of at least one of a coil, a spiral, a cuff, a rod, or a plate or a sheet in the form of an oval or a polygon.

7. The system of claim 6, wherein at least one of the uninsulated pick-up portion or the uninsulated delivery portion is formed from at least one of an uninsulated end of the conductor or from other conductive materials.

8. The system of claim 1, further comprising:

an electrical return conductor having

a collecting portion;

a returning portion; and

an insulated portion between the collecting portion and the returning portion, the collecting portion configured to collect a portion of the electrical current delivered to the target body tissue to return through the electrical return conductor in preference to returning through body tissue, and the returning portion forming an electrical termination that returns the portion of the electrical current to the second surface electrode via subcutaneous tissue and skin underlying the second surface electrode.

9. The system of claim 1, wherein the conductor is formed from at least one of a metal wire, carbon fibers, a conductive rubber or other conductive polymer, or a conductive salt solution in rubber.

10. The system of claim 1, wherein the first surface electrode and the second surface electrode include a conductive plate or a conductive sheet, a conductive gel electrode, a conductive rubber or polymer electrode that may be partially coated with an electrode paste or gel, or a moistened absorbent pad electrode.

11. The system of claim 1, further comprising a coating on one or both of the uninsulated pick-up portion or the uninsulated delivery portion, the coating being at least one of a conductive coating coating, an oxide layer, an anti-inflammatory agent, an antibacterial agent, an antibiotic, or a tissue ingrowth promoter.

12. The system of claim 1, wherein the implant is one implant from a plurality of implants, each of the plurality of implants configured to electrically stimulate target body tissue independently or in unison, each implant from the plurality of implants being implanted entirely under a subject'"'"'s skin and being of a sufficient length to extend to a different target body tissue, and the first surface electrode being one of a plurality of first surface electrodes and at least the first surface electrode and the second surface electrode configured to be positioned relative to the plurality of implants to stimulate the different target body tissues independently or in unison.

13. The system of claim 1, wherein the uninsulated pick-up portion is configured to pick up the portion of the electrical current via resistive coupling.

14. The system of claim 1, wherein the uninsulated pick-up portion is configured to pick up the portion of the electrical current via capacitive and resistive coupling.

15. A method, comprising:

implanting an implant in a body, the implant including a passive electrical conductor having an uninsulated pick-up portion and an uninsulated delivery portion, the uninsulated pick-up portion being configured to pick up at least a portion of an electric current flowing between a first surface electrode and a second surface electrode and to transmit the portion of the electric current to a target body tissue, the passive electrical conductor having an insulated body portion between the uninsulated pick-up portion and the uninsulated delivery portion;

positioning the first surface electrode and the second surface electrode in spaced relationship on, and in electrical contact with, the body, with the first surface electrode positioned over the uninsulated pick-up portion of the electrical conductor so the portion of the electric current is transmitted through the electrical conductor to the target body tissue; and

applying an electrical current between the first surface electrode and the second surface electrode to cause the portion of the electrical current to flow through the implant to be delivered to the target body tissue.

16. The method of claim 15, wherein the applied electrical current is in the form of direct current.

17. The method of claim 15, wherein the applied electrical current is in the form of alternating current.

18. The method of claim 15, wherein the applied electrical current is in the form of pulsatile current.

19. The method of claim 16, wherein:

the conductor has a length sufficient to extend, once implanted, from subcutaneous tissue located below the first surface electrode to a target body tissue.

20. The method of claim 19, wherein:

the uninsulated pick-up portion forms an electrical termination having a sufficient surface area such that, once implanted in subcutaneous tissue below the first surface electrode, the portion of the electric current flows through the conductor, in preference to flowing through body tissue between the first surface electrode and the second surface electrode, and

the uninsulated delivery portion forms an electrical termination to deliver the portion of the electric current to the target body tissue, once implanted.

21. The method of claim 20, wherein:

the electrical termination at one or both of the uninsulated pick-up portion and the uninsulated delivery portion is formed from the uninsulated end of the conductor, or from other conductive materials; and

the insulated portion extends from the uninsulated pick-up portion to the uninsulated delivery portion of the conductor.

22. The method of claim 21, wherein:

the electrical current is applied with a stimulator configured to be external to the subject'"'"'s body and to supply direct, pulsatile, or alternating current to the first surface electrode and the second surface electrode.

23. The method of claim 15, wherein at least one of the uninsulated pick-up portion or the uninsulated delivery portion is configured to include an enlarged surface area in the form of at least one of a coil, a spiral, a cuff, a rod, or a plate or a sheet in the form of an oval or a polygon.

24. The method of claim 15, further comprising:

implanting in the body a return conductor, the return conductor having a collecting portion and a returning portion and being insulated between the collecting portion and the returning portion, the collecting portion configured to collect a portion of the electrical current delivered to the target body tissue to return through the return conductor in preference to returning through body tissue, and the returning portion forming an electrical termination configured to return the portion of the electrical current to the second surface electrode via subcutaneous tissue and skin underlying the second surface electrode.

25. The method of claim 15, wherein the target body tissue includes at least one of a neural tissue in the peripheral nervous system or the central nervous system, a nerve, a muscle or an organ.

26. The method of claim 15, wherein the applying the electrical current to cause the portion of the electrical current to flow through the implant to stimulate the target body tissue is conducted to treat a condition including at least one of a movement disorder, a muscular disorder, incontinence, urinary retention, pain, epilepsy, a cerebrovascular disorder, a sleep disorder, an autonomic disorder, a disorder of vision, a hearing or balance disorder, or a neuropsychiatric disorder, to promote bone growth or wound healing, or to promote tissue regeneration.

27. The method of claim 15, the implant being one implant from a plurality of implants, the method further comprising implanting the plurality of implants to electrically stimulate more than one target body tissue independently or in unison, each implant from the plurality of implants being implanted entirely within the body and configured to extend to a different target body tissue, and

positioning a plurality of first surface electrodes and one or more second surface electrodes relative to the plurality of implants to stimulate the different target body tissues independently or in unison.

28. The method of claim 15, wherein the applying the electrical current includes applying a pulsatile current at a frequency in the range of between about 1 Hz and 100 Hz, alternatively in the range of between about 1 Hz and 50 Hz, or alternatively in the range of between about 1 Hz and 20 Hz.

29. The method of claim 15, wherein the applying includes applying the electrical current to block a target body tissue.

30. The method of claim 29, wherein applying the electrical current is conducted to treat at least one of urinary retention, incontinence, pain, epilepsy, a cerebrovascular disorder, a sleep disorder, an autonomic disorder, a disorder of vision, a hearing or a balance disorder, a neuropsychiatric disorder or a movement disorder.

31. The method of claim 29, wherein the target body tissue includes a neural tissue in the peripheral nervous system or the central nervous system or a nerve.

32. The method of claim 29, wherein the applying electrical current includes applying the current in the form of a cyclical waveform at a frequency in the range of between about 100 Hz and 30,000 Hz.

33. The method of claim 29, wherein the applying the electrical includes applying the current in the form of a cyclical waveform at a frequency in the range of between about 100 Hz and 20,000 Hz, alternatively in the range of between about 100 Hz and 10,000 Hz, alternatively in the range of between about 200 Hz and 5,000 Hz.

34. The method of claim 29, the implant being one implant from a plurality of implants, the method further comprising implanting a plurality of implants to electrically block more than one target body tissue independently or in unison, each implant from the plurality of implants being implanted entirely in the body and configured to extend to a different target body tissue, and

positioning a plurality of first surface electrodes and one or more second surface electrodes relative to the plurality of implants to block the different target body tissues independently or in unison.

35. The method of claim 15, wherein the uninsulated pick-up portion is configured to pick up the portion of the electrical current via resistive coupling.

36. The method of claim 15, wherein the uninsulated pick-up portion is configured to pick up the portion of the electrical current via capacitive and resistive coupling.

37. An implant, comprising:

a passive electrical conductor configured to be in electrical communication with a first surface electrode and a second surface electrode when the passive electrical conductor is implanted, the passive electrical conductor including

an uninsulated pick-up portion being configured to pick up at least a portion of an electric current flowing between the first surface electrode and the second surface electrode;

an uninsulated delivery portion configured to deliver the portion of the electric current to a target body tissue; and

an insulated body portion disposed between the uninsulated pick-up portion and the uninsulated delivery portion.

38. The implant of claim 37, wherein at least one of the uninsulated pick-up portion or the uninsulated delivery portion is configured to include an enlarged surface area in the form of at least one of a coil, a spiral, a cuff, a rod, or a plate or a sheet in the form of an oval or a polygon.

39. The implant of claim 38, wherein:

the first surface electrode and the second surface electrode are configured to make electrical contact with a subject'"'"'s skin; and

the passive electrical conductor has a length sufficient to extend, once implanted, from subcutaneous tissue located below the first surface electrode to the target body tissue which is to be stimulated.

40. The implant of claim 39, wherein:

the uninsulated pick-up portion forms an electrical termination having a sufficient surface area such that, once implanted in subcutaneous tissue below the first surface electrode, the portion of the electric current flows through the conductor, in preference to flowing through body tissue between the first surface electrode and the second surface electrode, and

the uninsulated delivery portion forms an electrical termination to deliver the portion of the electric current to the target body tissue, once implanted.

41. The implant of claim 40, wherein:

the electrical termination at one or both of the uninsulated pick-up portion and the uninsulated delivery portion is formed from the uninsulated end of the conductor, or from other conductive materials; and

the insulated portion extends from the uninsulated pick-up portion to the uninsulated delivery portion of the conductor.

42. The implant of claim 37, further comprising:

an electrical return conductor having

a collecting portion;

a returning portion; and

an insulated body portion between the collecting portion and the returning portion, the collecting portion configured to collect a portion of the electrical current delivered to the target body tissue to return through the electrical return conductor in preference to returning through body tissue, and the returning portion forming an electrical termination that returns the portion of the electrical current to the second surface electrode via subcutaneous tissue and skin underlying the second surface electrode.

43. The implant of claim 37, wherein the conductor is formed from at least one of a metal wire, carbon fibers, a conductive rubber or other conductive polymer, or a conductive salt solution in rubber.

44. The implant of claim 37, wherein at least one of the uninsulated pick-up portion and the uninsulated delivery portion of the passive electrical conductor includes an enlarged surface area in the form of a coil, a spiral, a cuff, a rod, or a plate or a sheet in the form of an oval or a polygon.

45. The implant of claim 37, further comprising a coating on at least one of the uninsulated pick-up portion or the uninsulated delivery portion, the coating being at least one of a conductive coating, an oxide layer, an anti-inflammatory agent, an antibacterial agent, an antibiotic, or a tissue ingrowth promoter.

46. The implant of claim 37, wherein the uninsulated pick-up portion of the passive electrical conductor is configured to pick up the portion of the electrical current via resistive coupling.

47. The implant of claim 37, wherein the uninsulated pick-up portion of the passive electrical conductor is configured to pick up the portion of the electrical current via capacitive and resistive coupling.

48. An electrical circuit, comprising:

a first circuit portion including a first surface electrode and a second surface electrode collectively configured to transmit electrical current to at least one of a target nerve or a target muscle, the first surface electrode and the second surface electrode configured to be electrically coupled to a skin surface;

a second circuit portion including a passive electrical conductor having an uninsulated pick-up portion and an uninsulated delivery portion, the uninsulated pick-up portion being configured to pick up at least a portion of an electric current flowing between the first surface electrode and the second surface electrode and to transmit the portion of the electric current through the conductor to the target body tissue, the passive electrical conductor being insulated between the uninsulated pick-up portion and the uninsulated delivery portion,

the first circuit portion and the second circuit portion configured to be electrically coupled via bodily tissue disposed between the first circuit portion and the second circuit portion when the second circuit portion is implanted under the skin surface.

49. The circuit of claim 48, wherein at least one of the uninsulated pick-up portion or the uninsulated delivery portion is configured to include an enlarged surface area in the form of at least one of a coil, a spiral, a cuff, a rod, or a plate or a sheet in the form of an oval or a polygon.

50. The circuit of claim 48, wherein the first surface electrode and the second surface electrode are directly coupled to the skin surface.

51. The circuit of claim 48, wherein the second circuit portion is configured to extend through layers of skin under the skin surface to the target tissue.

52. The circuit of claim 48, wherein the uninsulated pick-up portion is configured to pick up the portion of the electrical current via resistive coupling.

53. The of claim 48, wherein the uninsulated pick-up portion is configured to pick up the portion of the electrical current via capacitive and resistive coupling.