SELF FIXING SPINAL CORD STIMULATION LEAD AND DELIVERY SYSTEM

• US 20070055332A1
• Filed: 09/03/2005
• Published: 03/08/2007
• Est. Priority Date: 09/03/2005
• Status: Active Grant

• Current Assignee: Cirtec Medical Corp.
• Original Assignee: Enpath Medical, Inc. (Integer Holdings Corporation Inc)
• Inventors: SWOYER, John
• Granted Patent: US 7,640,064 B2
• Time in Patent Office: Days
• US Class Current: 607/117
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0558 Anchoring or fixation means therefor
• CPC Class Codes: A61N 1/057 Anchoring means; Means for fixing the head inside the heart

Abstract

Devices and methods for implanting a spinal neurological lead having at least one wing or flap extending transversely from the lead body. The wing can have a first wrapped configuration in which the wing is constrained against the lead body and a second unwrapped configuration is which the wing is unconstrained and allowed to extend outwardly. The wing can be biased to unwrap such that the wing tips change in angular position when viewed from the end, and in transverse extension when viewed from the top, but not in longitudinal position when viewed from the side. A pusher tube can be used to urge the lead from a delivery catheter, allowing the wing or wings to extend to urge a surface electrode toward the spinal cord, to maintain longitudinal position, and to be passively fixed over time. Leads according to the present invention can provide improved longitudinal stability after the lead electrode position has been properly fixed with respect to the spinal cord.

Claims

1. An implantable medical electrical lead comprising:

an elongate lead body having a length, a proximal region, and a distal region;

at least one electrical conductor disposed along the length of the lead body;

at least one electrode disposed in the lead body distal region and in electrical continuity with the at least one conductor; and

at least one flap not carrying an electrode secured to the distal region, in which the flap has a first position in which the flap is disposed close to the lead body and a second position in which the flap is extended away from the lead body.

2. The lead of claim 1, wherein the lead body distal region has a first side, and a second side disposed substantially opposite the first side, in which the at least one electrode is disposed on the first side, and in which the at least one flap is secured to the distal region second side.

3. The lead of claim 1, in which the flap has two portions, in which the flap is attached to the lead body substantially tangentially at a location between the two flap portions.

4. The lead of claim 3, in which the flap has opposite edges on opposite sides of the lead body, in which the edges are configured to move away from each other in moving from the first position to the second position.

5. The lead of claim 1, in which the flap is biased to move from the first position to the second position when unconstrained.

6. The lead of claim 1, in which the flap is secured to the lead body at a location which demarcates the flap into a first portion and a second portion, in which the flap securing location lies substantially in a line which extends through a lead body center axis and through the electrode.

7. The lead of claim 1, in which the flap has a first portion and a second portion both attached to the lead body, in which the first and second portions extend away from each other in substantially opposite directions when unconstrained.

8. The lead of claim 7, in which the flap first and second portions are contiguous and can lie in substantially one plane when unconstrained.

9. The lead of claim 7, in which the lead has a longitudinal center axis, and in which the flap first and second portions lie in substantially the same plane which does not extend through the lead longitudinal center axis.

10. The lead of claim 7, in which the lead has a longitudinal center axis, in which the flap is configured to move from the first to the second position by varying in angular position with respect to the lead longitudinal center axis when viewed from the distal end, and to vary in extension distance from the lead longitudinal center axis when viewed from the top, but to not substantially vary in longitudinal position when viewed from the side.

11. The lead of claim 7, in which the flap is configured to move from the first to the second position without substantially changing in longitudinal position with respect to the lead, in which the first and second portions are wrapped in opposite winding direction relative to each other when in the first position.

12. The lead of claim 7, in which the lead has a longitudinal center axis, in which the flap is configured to move from the first to the second position such that a point on at least one of the flap portions moves substantially within a plane that is orthogonal to the lead longitudinal center axis.

13. The lead of claim 7, in which the flap is configured to move from the first to the second position such that the flap moves away from the surface electrode.

14. The lead of claim 7, in which the flap is configured to move from the first to the second position such that the flap splays away from the electrode further than the furthest point of the lead body lying in the same transverse plane that includes both the electrode and the furthest point of the lead body.

15. A system comprising the lead of claim 1, further comprising a tubular catheter having a lumen configured to receive the lead while in the lead second position.

16. The system of claim 15, further comprising a pusher element adapted to be disposed along the catheter to urge the lead distally from the delivery catheter.

17. The system of claim 16, in which the pusher element is a pusher tube adapted to be received over the lead body and within the catheter lumen.

18. The system of claim 15, in which the catheter has at least one electrically conductive distal region and an electrical conductor disposed along at least some of the catheter length and in electrical communication with the conductive distal region.

19. The system of claim 15, in which the lead body has lumen within for at least part of its length, further comprising a stylet configured to be received within the lead body lumen.

20. The system of claim 19, further comprising a pusher element adapted to be disposed along the lead body to urge the lead distally from the delivery catheter.

21. A method for placing an implantable medical lead along a spinal cord, the method comprising:

advancing a catheter having a lumen, with the implantable medical lead disposed within the lumen, into the epidural space, wherein the lead has a proximal region, a distal region, at least one electrode disposed near the distal region, and an electrical conductor extending from the proximal region to the electrode, wherein the lead has at least one wing secured to the lead body and constrained toward the lead body; and

forcing the lead distal region and wing out of the catheter near the spinal cord, allowing the wing to extend away from the spinal cord and allowing the electrode to bear toward the spinal cord.

22. The method of claim 21, in which the forcing includes urging a pusher element disposed along the lead body to force the lead out of the catheter.

23. The method of claim 22, in which the pusher element is a pusher tube and the forcing includes urging the pusher tube disposed over the lead body and within the catheter lumen to force the lead out of the catheter.

24. The method of claim 23, in which the lead body includes a removable stylet disposed within during at least some of the forcing.

25. The method of claim 22, in which the pusher element is a removable stylet disposed within the lead body during at least some of the forcing.

26. The method of claim 22, in which the forcing includes bringing the pusher tube to bear on the lead wing.

27. The method of claim 21, in which the allowing the wing to extend is substantially limited to extending such that the wing does not change its longitudinal position with respect to the lead body during the extension.

28. The method of claim 21, in which the lead wing has a longitudinal center region which is secured to the lead body on an opposite side of the lead body from the electrode, such that the wing extending can force the lead electrode against the spinal cord if the lead wing is extended against surrounding tissue.

29. The method of claim 28, in which the lead wing longitudinal center region demarcates the wing into two portions which can lie in substantially the same plane when unconstrained.

30. The method of claim 21, in which the lead wing is disposed on an opposite side of the lead body from the electrode, such that the wing opening urges the electrode in a direction away from the wing.

31. The method of claim 21, in which the catheter has an electrically conductive distal region, further comprising urging the catheter electrically conductive region near the spinal cord and determining electrical and/or physiological properties using the electrically conductive distal portion.

32. The method of claim 31, in which the determining electrical properties includes stimulating the spinal cord using the electrically conductive catheter distal region.

33. The method of 21, further comprising urging the lead body partially out of the catheter to dispose the electrode near the spinal cord and determining electrical and/or physiological properties using the electrode, followed by completely urging the lead body out of the catheter.