Implantable medical lead with helical reinforcement

• US 20060089695A1
• Filed: 04/29/2005
• Published: 04/27/2006
• Est. Priority Date: 10/21/2004
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Olsen, James M., Bolea, Stephen L., Bischoff, Thomas C., Cross, Thomas E. Jr.
• Granted Patent: US 7,519,432 B2
• Time in Patent Office: Days
• US Class Current: 607/122
• CPC Class Codes: A61N 1/056 Transvascular endocardial electrode systems

Abstract

An implantable lead has a lead body construction designed to accommodate loading forces exerted on the lead body during patient movement. The lead body may be sufficiently stretchable to resist forces that could otherwise cause lead failure, axial migration of the electrodes, anchor damage, or tissue damage. Increasing stretchability of a lead body can also increase the vulnerability of the lead body to flex fatigue, buckling fatigue, kinking, and crush. Therefore, the lead described herein includes a reinforcement to create a lead body that is resistant to flex fatigue, buckling fatigue, kinking and crush.

Claims

1. A medical lead for use with an implantable medical device comprising:

a lead body with an outer jacket;

a stylet guide tube disposed inside the outer jacket;

a reinforcement disposed between the stylet guide tube and the outer jacket, wherein the reinforcement defines substantially helical channel that extends about the stylet guide tube; and

conductors that extend about the stylet guide tube in the helical channel defined by the reinforcement.

2. The medical lead of claim 1, wherein the reinforcement includes a coil that is coiled about the stylet guide tube, wherein the substantially helical channel is formed between adjacent turns in the coil.

3. The medical lead of claim 2, wherein the stylet guide tube comprises a coiled wire formed in a tight coil such that the stylet guide tube forms a substantially continuous cylindrical shape.

4. The medical lead of claim 3, wherein the stylet guide tube is coiled in a first direction and the reinforcement is coiled in a second direction different from the first direction.

5. The medical lead of claim 2, wherein the reinforcement comprises an insulated metal wire.

6. The medical lead of claim 5, wherein the insulated wire comprises a metallic alloy selected from a group consisting of nitinol, nickel-cobalt-chromium-molybdenum alloy, titanium, and titanium alloy.

7. The medical lead of claim 5, wherein the insulated wire comprises urethane insulation.

8. The medical lead of claim 1, wherein the conductors do not overlap the reinforcement and the reinforcement does not overlap the conductors.

9. The medical lead of claim 1, wherein the reinforcement defines a substantially cylindrical outer surface, and includes a raised helical thread formed on an outside of the cylindrical outer surface, wherein the substantially helical channel is formed between adjacent turns raised helical thread.

10. The medical lead of claim 9, further comprising a reinforcement wire embedded within the raised helical thread.

11. The medical lead of claim 10, wherein the reinforcement wire comprises a metallic alloy selected from a group consisting of nitinol, nickel-cobalt-chromium-molybdenum alloy, and titanium or titanium alloys.

12. The medical lead of claim 10, wherein the raised helical thread comprises one of an acme thread or a trapezoidal thread.

13. The medical lead of claim 10, wherein the conductors do not overlap the raised helical thread.

14. The medical lead of claim 1, wherein the outer jacket comprises:

a first insulative layer;

a second insulative layer inside the first insulative layer; and

a coiled wire embedded between the first layer and the second layer of the outer jacket.

15. The medical lead of claim 1, wherein the outer jacket comprises one of a polyurethane material or a silicone material.

16. The medical lead of claim 1, wherein the conductors comprise insulated braided silver cored wire.

17. The medical lead of claim 1, wherein each of the conductors comprise a nickel-cobalt-chromium-molybdenum alloy wire.

18. The medical lead of claim 1, wherein the conductors comprise braided silver cored wire insulated with ethylene-tetrafluoroethylene (ETFE).

19. The medical lead of claim 1, wherein the lead body has a length in a range of approximately 30 cm to 36 cm.

20. The medical lead of claim 1, wherein the lead body has a length of approximately 33 centimeters.

21. The medical lead of claim 1, wherein the lead body has an axial stiffness in a range of approximately 0.105 kg/cm/cm to approximately 0.35 kg/cm/cm.

22. The medical lead of claim 1, wherein the lead body has an axial stiffness in a range of approximately 0.105 kg/cm/cm to approximately 0.23 kg/cm/cm.

23. The medical lead of claim 1, wherein the lead body exhibits an axial stiffness in the presence of elastic deformation under an axial elongation of approximately ten percent to approximately thirty percent.

24. The medical lead of claim 1, further comprising

one or more electrodes at a distal end of the lead body;

and

one or more electrical contacts at a proximal end of the lead body,

wherein each of the conductors electrically couples one of the electrodes to one of the electrical contacts.

25. An implantable medical device comprising:

a housing;

an implantable pulse generator, within the housing, that generates electrical stimulation pulses; and

an implantable lead, extending from the housing, and comprising a lead body with an outer jacket, a stylet guide tube disposed inside the outer jacket, a reinforcement disposed between the stylet guide tube and the outer jacket, wherein the reinforcement defines substantially helical channel that extends about the stylet guide tube, and conductors that extend about the stylet guide tube in the helical channel defined by the reinforcement.

26. The device of claim 25, wherein the reinforcement includes a coil that is coiled about the stylet guide tube, wherein the substantially helical channel is formed between adjacent turns in the coil.

27. The device of claim 26, wherein the stylet guide tube comprises a coiled wire formed in a tight coil such that the stylet guide tube forms a substantially continuous cylindrical shape.

28. The device of claim 27, wherein the stylet guide tube is coiled in a first direction and the reinforcement is coiled in a second direction different from the first direction.

29. The device of claim 25, wherein the reinforcement defines a substantially cylindrical outer surface, and includes a raised helical thread formed on an outside of the cylindrical outer surface, wherein the substantially helical channel is formed between adjacent turns raised helical thread.

30. The device of claim 29, further comprising a reinforcement wire embedded within the raised helical thread.

31. The device of claim 29, wherein the raised helical thread comprises one of an acme thread or a trapezoidal thread.

32. The device of claim 29, wherein the conductors do not overlap the raised helical thread.