Wire Configuration and Method of Making for an Implantable Medical Apparatus

• US 20100256718A1
• Filed: 04/06/2009
• Published: 10/07/2010
• Est. Priority Date: 04/06/2009
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Wang, Ling, Li, Bernard Q.
• Granted Patent: US 8,639,352 B2
• Time in Patent Office: Days
• US Class Current: 607/116
• CPC Class Codes: A61N 1/0472 Structure-related aspects
• CPC Class Codes: A61N 1/0488 Details about the lead
• 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 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

A filar includes an inner conductive core that is formed of a low-resistivity material such as silver having a resistivity of less than 20 μΩ per centimeter. A conductive coil is provided around the core to form a filar. This coil is formed of a biocompatible alloy or super alloy having an ultimate tensile strength (UTS) of between 150 kilo pounds per square inch (ksi) and 280 ksi at room temperature. Examples of such alloys include CoCrMo, CoFeCrMo, and CoFeNiCrMo. In one specific embodiment, the alloy is MP35N (CoNiCrMo), which may be low-titanium (“low-ti”) MP35N. One or more such filars may be included within a wire. This wire may be carried by an implantable medical apparatus such as a lead, lead extension, or catheter. The wire may electrically couple elements such as connector electrodes to conducting electrodes or sensors.

Claims

1. An implantable medical apparatus carrying a conducting electrode and a connector electrode, comprising:

a body of the apparatus; and

a conductive wire carried by the body and electrically coupling the conducting electrode and the connector electrode, the conductive wire comprising;

a silver core; and

an MP35N coil positioned around the silver core.

2. The apparatus of claim 1, wherein the MP35N coil is formed of a single filament.

3. The apparatus of claim 1, wherein the MP35N coil is formed of multiple filaments.

4. The apparatus of claim 1, wherein the MP35N coil is formed of a filament having a diameter of between 0.025 millimeters and 0.102 millimeters.

5. The apparatus of claim 1, wherein turns of the coil are disposed at an angle of between 0 and 45 degrees relative to an axis that is substantially perpendicular to a longitudinal axis of the body.

6. The apparatus of claim 1, wherein the conductive wire comprises multiple filars each comprising a respective silver core and an MP35N coil positioned around the silver core.

7. The apparatus of claim 6, wherein a first subset of the multiple filars is electrically-insolated from a second subset of the multiple filars.

8. The apparatus of claim 1, wherein the coil is formed of an MP35N filament that is annealed at a temperature exceeding the melting point of the silver core.

9. An implantable medical apparatus carrying two elements, each of the elements being capable of at least one of receiving, transmitting, and conducting an electrical signal, the apparatus comprising:

a silver core extending between, and electrically coupling, the two elements; and

an MP35N coil wound around, and electrically coupled to, the silver core.

10. The apparatus of claim 9, wherein the coil is formed of an MP35N filament drawn to a desired diameter at a temperature that is above the melting point of the silver core.

11. The apparatus of claim 10, wherein the desired diameter is between 0.025 millimeters and 0.102 millimeters.

12. The apparatus of claim 9, wherein the MP35N coil is formed of a single filament.

13. The apparatus of claim 9, wherein the MP35N coil is formed of multiple filaments.

14. The apparatus of claim 9, further comprising:

multiple silver cores extending between, and electrically coupling, the two elements; and

for each of the multiple silver cores, a respective MP35N coil wound around, and electrically coupled to, the respective silver core.

15. The apparatus of claim 14, wherein the MP35N coils and silver cores are twisted together in a wire.

16. The apparatus of claim 9, further including an electrically insulating polymer sheath surrounding the MP35N coil.

17. The apparatus of claim 9, further including at least one electrically-conductive joint formed of a fusible metal alloy bonding the MP35N coil to at least one of the two elements.

18. An implantable medical apparatus, comprising:

an MP35N coil; and

a silver core positioned within the coil.

19. The apparatus of claim 18, wherein the MP35N coil and the silver core are electrically and mechanically coupled.

20. The apparatus of claim 18, further comprising:

multiple MP35N coils; and

multiple silver cores, each positioned within a respective one of the multiple MP35N coils.

21. The apparatus of claim 18, further comprising:

a connector electrode ; and

an element to perform at least one of receiving, transmitting, and conducting an electrical signal; and

wherein at least one of the MP35N coil and the silver core electrically couple the connector electrode to the element.

22. The apparatus of claim 18, wherein the element is a conducting electrode or a sensor.

23. An implantable medical apparatus, comprising:

a core having a resistivity of less than 20 micro-ohms per centimeter; and

a coil surrounding the core formed of a biocompatible alloy having an ultimate tensile strength of between 150 kilo pounds per square inch (ksi) and 280 ksi at room temperature.

24. The apparatus of claim 23, wherein the core is selected from a group consisting of silver, tantalum, a tantalum alloys, niobium, niobium alloys, palladium, palladium alloys, platinum and platinum alloys.

25. The apparatus of claim 24, wherein the biocompatible alloy is selected from a group consisting of cobalt-based alloys and titanium-based alloys.

26. A method of manufacturing a medical apparatus, comprising:

providing a silver core;

winding an MP35N filament around the silver core to form a conductive wire; and

including the wire within a body of the medical apparatus.

27. The method of claim 26, further comprising:

annealing MP35N at a temperature above the melting point of the silver core; and

drawing the MP35N to a diameter of between 0.025 millimeters and 0.102 millimeters to form the filament.

28. The method of claim 26, wherein the medical apparatus has a connector electrode and a conducting electrode, and further comprising electrically coupling the connector electrode and the conducting electrode via the wire.

29. The method of claim 28, further comprising forming an electrically-conductive joint to bond the wire to one of the connector electrode and the conducting electrode.

30. The method of claim 26, further comprising:

providing multiple silver cores;

providing multiple MP35N filaments;

winding each of the multiple MP35N filaments around a respective one of the multiple silver cores to form a respective filar; and

forming the conductive wire of the multiple filars.

31. The method of claim 26, further including winding multiple MP35N filaments around the silver core to form the conductive wire.