Electronic lead for a medical implant device, method of making same, and method and apparatus for inserting same

• US 20030050680A1
• Filed: 12/27/2001
• Published: 03/13/2003
• Est. Priority Date: 09/07/2001
• Status: Active Grant

• Current Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Minimed Incorporated (Medtronic Plc)
• Inventors: Shah, Rajiv, Gibson, Scott R., Chernoff, Edward, Byers, Charles
• Granted Patent: US 6,671,554 B2
• Time in Patent Office: Days
• US Class Current: 607/116
• 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 1/3752 Details of casing-lead connections
• CPC Class Codes: Y10S 439/909 Medical use or attached to human body

Abstract

An implantable coaxial lead includes a cable with male and female connectors. The cable includes inner and outer helical coils separated by an inner insulator tube, with an outer insulator tube surrounding the outer helical coil. The male connector includes an outer conductive cylinder, a conductive pin and an insulator molded in between. For increased strength, a braided cylinder, infused with rubber, is included at the juncture of the male connector and the cable. The female connector includes a cylinder formed by two conducting body elements and an intervening insulating body element. The female connector includes respective conductive tension elements configured to engage the male connector. A first seal is provided between the conductive tension members for electrical isolation and tactile feedback. An insertion tool includes a cylinder with a hollow bore and detachable head, and a rod for pulling the lead through the cylinder.

Claims

1. An electrical connecting system comprising:

a first connector having an electrically conductive element and an electrically conductive surface;

a second connector comprising;

a connector body defining an inner cavity with a first end and a second end, wherein said inner cavity is open at said first end, said inner cavity configured to receive said first connector;

a first electrically conductive tension member within said inner cavity, said first conductive tension member configured to engage said conductive element to form a first electrical channel; and

a second electrically conductive tension member within said inner cavity, said second conductive tension member configured to engage said conductive surface to form a second electrical channel.

2. The system of claim 1, wherein said second connector has an insertion force of no greater than fourteen Newtons with respect to said first connector.

3. The system of claim 1, wherein said second connector has a retention force of at least five Newtons with respect to said first connector.

4. The system of claim 1, wherein said first connector and said second connector are configured for unidirectional mechanical engagement.

5. The system of claim 1, wherein:

the first connector further comprises an insulating member configured to electrically insulate the conductive element from said conductive surface; and

the second connector further comprises a first seal within said inner cavity, said first seal configured to engage said insulating member to isolate said first electrical channel from said second electrical channel.

6. The system of claim 5, wherein:

said first seal comprises an umbrella-shaped ridge; and

said insulating member comprises a seal catch configured to engage said umbrella-shaped ridge.

7. The system of claim 6, wherein said first seal and said seal catch form a tactile feedback mechanism.

8. The system of claim 5, wherein said second connector further comprises a second seal configured to engage said first connector to isolate said inner cavity.

9. The system of claim 8, wherein said second seal comprises an annular ring of flexible material, said annular ring having a plurality of annular ridges that contact said first connector while said first connector is within said inner cavity.

10. The system of claim 9, wherein said flexible material is molded rubber.

11. The system of claim 8, wherein said second seal is located within a first annular groove substantially adjacent to said first end of said inner cavity.

12. The system of claim 5, wherein said connector body comprises:

a first conductive body member defining said first end of said inner cavity;

a second conductive body member defining said second end of said inner cavity; and

a middle insulator coupled between said first conductive body member and said second conductive body member.

13. The system of claim 12, wherein said first conductive body member is comprised of steel.

14. The system of claim 12, wherein said second conductive body member is comprised of steel.

15. The system of claim 12, wherein said middle insulator is comprised of a resilient, nonconductive material.

16. The system of claim 15, wherein said resilient, nonconductive material is polysulfone.

17. The system of claim 12, wherein the interior of said first conductive body member comprises an annular groove wherein said first conductive tension member is located.

18. The system of claim 17, wherein said second connector further comprises a wear-resistant member fitted into said annular groove between said first conductive tension member and said middle insulator.

19. The system of claim 18, wherein said wear resistant member comprises a washer.

20. The system of claim 17, wherein said first conductive tension member comprises a toroidal spring.

21. The system of claim 12, wherein said middle insulator comprises an annular groove in which said first seal is seated.

22. The system of claim 12, wherein the interior of said second conductive body member comprises an annular groove wherein said second conductive tension member is located.

23. The system of claim 22, wherein said second connector further comprises a wear-resistant member fitted into said annular groove between said second conductive tension member and said middle insulator.

24. The system of claim 23, wherein said wear resistant member comprises a washer.

25. The system of claim 24, wherein said second conductive tension member comprises a toroidal spring.

26. The system of claim 1, further comprising a two-conductor electrical cable coupled to said first connector.

27. The system of claim 26, wherein said cable is coupled to said first connector through a braided tube adjacent to said first connector.

28. The system of claim 27, wherein said braided tube is infused with a flexible insulating material.

29. The system of claim 28, wherein said braided tube is overmolded with said flexible insulating material to have about the same diameter as said cable.

30. The system of claim 29, wherein said first connector has a diameter less than or about equal to the diameter of said cable.

31. The system of claim 27, wherein said braided tube comprises a steel mesh.

32. The system of claim 26, wherein said cable comprises:

an outer coil comprising a first helical ribbon conductor;

an inner coil within said outer coil, said inner coil comprising a second helical ribbon conductor;

an inner insulating tube between said inner coil and said outer coil; and

an outer insulating tube encompassing said outer coil.

33. The system of claim 32, wherein said first helical ribbon conductor comprises a plurality of adjacent conductive wires configured in a ribbon strip that is twisted about a central axis to form a helix.

34. The system of claim 33, wherein each of said conductive wires comprises a silver core surrounded by a cobalt alloy layer.

35. The system of claim 33, wherein said ribbon strip is configured to have a maximum distance by which any one of said plurality of adjacent wires may be offset from said ribbon strip.

36. The system of claim 32, wherein said inner coil is coupled to said conductive pin and said outer coil is coupled to said conductive surface.

37. The system of claim 12, further comprising a two-conductor electrical cable coupled to said second connector.

38. The system of claim 37, wherein said cable comprises:

an outer coil comprising a first helical ribbon conductor;

an inner coil within said outer coil, said inner coil comprising a second helical ribbon conductor;

an inner insulating tube between said inner coil and said outer coil; and

an outer insulating tube encompassing said outer coil.

39. The system of claim 38, wherein said first helical ribbon conductor comprises a plurality of adjacent conductive wires configured in a ribbon strip that is twisted about a central axis to form a helix.

40. The system of claim 39, wherein each of said conductive wires comprises a silver core surrounded by a cobalt alloy layer.

41. The system of claim 39, wherein said ribbon strip is configured to have a maximum distance by which any one of said plurality of adjacent wires may be offset from said ribbon strip.

42. The system of claim 38, wherein:

said inner coil is coupled to said first conductive body member; and

said outer coil wraps around an exterior surface of said connector body; and

said outer coil is electrically coupled to an external surface of said second conductive body member.

43. The system of claim 42, further comprising an electrically insulating layer around said exterior surface of said connector body and said outer coil.

44. The system of claim 43 applied to an implant patient, wherein said insulating layer comprises means for suturing said second connector within said implant patient.

45. A method for forming an electrical connector, comprising:

providing a first conductive body member, a second conductive body member and an insulating body member, wherein each of said first conductive body member, said second conductive body member and said insulating body member have a first end and a second end and define an interior cavity;

disposing a first conductive tension member in a first annular groove within said interior cavity of said first conductive body member;

disposing said first end of said insulating body member in said second end of said first conductive body member;

disposing a second conductive tension member in a second annular groove within said interior cavity of said second conductive body member; and

disposing said second end of said insulating body member in said first end of said second conductive body member.

46. The method of claim 45, further comprising disposing an annular seal in a third annular groove within said interior cavity of said second conductive body member adjacent to said second end of said second conductive body member.

47. The method of claim 45, further comprising providing a nonconductive surface over the exterior of said first conductive body member.

48. The method of claim 45, further comprising:

coupling a first conductive coil to an electrically conductive stem on said first end of said first conductive body member, wherein said first conductive coil forms a first electrical channel with said first conductive body member and said first conductive tension member; and

pulling a second conductive coil around the exterior of said first conductive body member and the exterior of said insulating body member; and

coupling said second conductive coil to the exterior of said second conductive body member, wherein said second conductive coil forms a second electrical channel with said second conductive body member and said second conductive tension member.

49. The method of claim 48, further comprising forming a nonconductive layer around the exterior of said second conductive coil.

50. The method of claim 45, further comprising forming an annular seal in a third annular groove within said interior cavity of said insulating body member.

51. The method of claim 50, wherein said step of forming an annular seal comprises forming an umbrella-shaped ridge configured to provide tactile feedback when engaged.

52. The method of claim 45, further comprising:

fitting a first wear-resistant member between said first conductive tension member and said insulating body member; and

fitting a second wear-resistant member between said second conductive tension member and said insulating body member.

53. A method of forming an electrical connector, comprising:

coupling a first end of a flexible braided cylinder to an outer insulating cylindrical member surrounding a first conductive coil and a second conductive coil.

coupling said first conductive coil to a conductive element that projects out from a first end of a conductive cylindrical member;

coupling said flexible braided cylinder to a second end of said conductive cylindrical member;

coupling a second conductive coil to said first end of said conductive cylindrical member;

molding an insulating member between said conductive cylinder and said conductive element; and

infusing said flexible braided cylinder with a flexible insulating material.

54. The method of claim 53, wherein said step of infusing said flexible braided cylinder comprises:

molding said flexible insulating material around said flexible braided cylinder until said flexible braided cylinder is of substantially the same diameter as said outer insulating cylindrical member.

55. The method of claim 54, wherein said step of molding said flexible insulating material comprises:

molding a ridge pattern on said flexible braided cylinder; and

molding over said ridge pattern to meet the diameter of said outer insulating member.

56. The method of claim 53, wherein said step of molding said insulating member comprises forming an umbrella-shaped seal ridge on a portion of said insulating member that projects beyond said first end of said conductive cylindrical member.

57. A coaxial cable having a first end and a second end, comprising:

an outer coil comprising a first helical ribbon conductor;

an inner coil within said outer coil, said inner coil comprising a second helical ribbon conductor;

an inner insulating tube between said inner coil and said outer coil; and

an outer insulating tube encompassing said outer coil.

58. The cable of claim 57, wherein said first helical ribbon conductor comprises a plurality of adjacent conductive wires configured in a ribbon strip that is twisted about a central axis to form a helix.

59. The cable of claim 58, wherein each of said conductive wires comprises a silver core surrounded by a cobalt alloy layer.

60. The cable of claim 58, wherein said ribbon strip is configured to have a maximum distance by which any one of said plurality of adjacent wires may be offset from said ribbon strip.

61. The cable of claim 57, further comprising a flexible, cylindrical strengthening member adjoining said outer insulating tube at said first end, said strengthening member encompassing said outer coil.

62. The cable of claim 61, wherein said flexible, cylindrical strengthening member comprises a braided cylinder.

63. The cable of claim 62, wherein said braided cylinder is infused with rubber.

64. An insertion apparatus for a lead having a connector, comprising:

a rigid elongated member having a hollow bore, a first end and a second end;

a bullet-shaped member detachably coupled to said first end of said rigid elongated member;

a rod configured to slide within said hollow bore, a length of said rod being greater than a length of said rigid elongated member; and

a connector member on a first end of said rod, said connector member configured to engage said connector of said lead.

65. The apparatus of claim 64, wherein said first end of said rigid elongated member is threaded to enable said bullet-shaped member to be screwed on and off.

66. The apparatus of claim 64, wherein a handle is attached to a second end of said rod.

67. The apparatus of claim 64, wherein said rigid elongated member is curved.

68. The apparatus of claim 64, wherein said rigid elongated member is straight.

69. The apparatus of claim 64, wherein the exterior of said rigid elongated member is composed of surgical material.

70. A method for inserting a lead into a patient, comprising:

inserting a rigid elongated member into a first incision;

guiding said rigid elongated member through fatty tissue of said patient until a first end of said rigid elongated member protrudes from a second incision;

removing a bullet-shaped member from said first end of said rigid elongated member to expose a hollow bore in said rigid elongated member;

passing a rod through said hollow bore until a connector member at a first end of said rod is exposed;

engaging a first connector of a lead with said connector member;

pulling said rod through said hollow bore until said first connector and a second connector of said lead are exposed on respective ends of said rigid elongated member; and

extracting said rigid elongated member from said patient with said lead remaining in said patient.

71. The method of claim 70, further comprising suturing in place at least one of said first connector and second connector.

72. The method of claim 70, further comprising:

connecting said first connector of said lead to a first implanted device; and

connecting said second connector of said lead to a second implanted device.

73. A female connector for receiving a male connector having an electrically conductive element and an electrically conductive surface, comprising:

a connector body defining an inner cavity with a first end and a second end, wherein said inner cavity is open at said first end, said inner cavity configured to receive said male connector;

a first electrically conductive tension member within said inner cavity, said first conductive tension member configured to engage said conductive element to form a first electrical channel; and

a second electrically conductive tension member within said inner cavity, said second conductive tension member configured to engage said conductive surface to form a second electrical channel.

74. The female connector of claim 73 having an insertion force of no greater than fourteen Newtons with respect to said male connector.

75. The female connector of claim 73 having a retention force of at least five Newtons with respect to said male connector.

76. The female connector of claim 73 being mechanically unidirectional with respect to said male connector.

77. The female connector of claim 73, further comprising:

a first seal within said inner cavity, said first seal configured to engage said male connector to isolate said first electrical channel from said second electrical channel.

78. The female connector of claim 77, wherein said first seal comprises an umbrella-shaped ridge.

79. The female connector of claim 78, wherein said umbrella-shaped ridge has a forward angle and a rearward angle.

80. The female connector of claim 78, wherein said first seal is a tactile feedback mechanism.

81. The female connector of claim 77, further comprising a second seal configured to engage said male connector to isolate said inner cavity.

82. The female connector of claim 81, wherein said second seal comprises an annular ring of flexible material, said annular ring having a plurality of annular ridges.

83. The female connector of claim 82, wherein said flexible material is molded rubber.

84. The female connector of claim 83, wherein said second seal is located within a first annular groove substantially adjacent to said first end of said inner cavity.

85. The female connector of claim 77, wherein said connector body comprises:

a first conductive body member defining said first end of said inner cavity;

a second conductive body member defining said second end of said inner cavity; and

a middle insulator coupled between said first conductive body member and said second conductive body member.

86. The female connector of claim 85, wherein said first conductive body member is comprised of steel.

87. The female connector of claim 85, wherein said second conductive body member is comprised of steel.

88. The female connector of claim 85, wherein said middle insulator is comprised of a resilient, nonconductive material.

89. The female connector of claim 88, wherein said resilient, nonconductive material is polysulfone.

90. The female connector of claim 89, wherein the interior of said first conductive body member comprises an annular groove wherein said first conductive tension member is located.

91. The female connector of claim 90, further comprising a wear-resistant member fitted into said annular groove between said first conductive tension member and said middle insulator.

92. The female connector of claim 91, wherein said wear resistant member comprises a washer.

93. The female connector of claim 90, wherein said first conductive tension member comprises a toroidal spring.

94. The female connector of claim 85, wherein said middle insulator comprises an annular groove in which said first seal is seated.

95. The female connector of claim 85, wherein the interior of said second conductive body member comprises an annular groove wherein said second conductive tension member is located.

96. The female connector of claim 95, wherein said second connector further comprises a wear-resistant member fitted into said annular groove between said second conductive tension member and said middle insulator.

97. The female connector of claim 96, wherein said wear resistant member comprises a washer.

98. The female connector of claim 97, wherein said second conductive tension member comprises a toroidal spring.

99. The female connector of claim 85, further comprising a two-conductor electrical cable coupled to said second connector.

100. The female connector of claim 99, wherein said cable comprises:

an outer coil comprising a first helical ribbon conductor;

an inner coil within said outer coil, said inner coil comprising a second helical ribbon conductor;

an inner insulating tube between said inner coil and said outer coil; and

an outer insulating tube encompassing said outer coil.

101. The female connector of claim 100, wherein said first helical ribbon conductor comprises a plurality of adjacent conductive wires configured in a ribbon strip that is twisted about a central axis to form a helix.

102. The female connector of claim 101, wherein each of said conductive wires comprises a silver core surrounded by a cobalt alloy layer.

103. The female connector of claim 100, wherein said ribbon strip is configured to have a maximum distance by which any one of said plurality of adjacent wires may be offset from said ribbon strip.

104. The female connector of claim 100, wherein:

said inner coil is coupled to said first conductive body member; and

said outer coil wraps around an exterior surface of said connector body; and

said outer coil is electrically coupled to an external surface of said second conductive body member.

105. The female connector of claim 104, further comprising an electrically insulating layer around said exterior surface of said connector body and said outer coil.

106. The female connector of claim 105 applied to an implant patient, wherein said insulating layer comprises means for suturing said second connector within said implant patient.