IMPLANTABLE NEURAL STIMULATION ELECTRODE ASSEMBLIES AND METHODS FOR STIMULATING SPINAL NEURAL SITES

• US 20090319013A1
• Filed: 05/19/2009
• Published: 12/24/2009
• Est. Priority Date: 05/19/2008
• Status: Active Grant

• Current Assignee: Nevro Corporation
• Original Assignee: Nevro Corporation
• Inventors: Boling, C. Lance, Caparso, Anthony V.
• Granted Patent: US 8,880,176 B2
• Time in Patent Office: Days
• US Class Current: 607/117
• CPC Class Codes: A61N 1/0553 Paddle shaped electrodes, e.g. for laminotomy

Abstract

An implantable neurostimulation electrode assembly comprises a first electrode unit and a second electrode unit configured to be arranged in a side-by-side configuration. The first electrode unit includes a dielectric first paddle, a plurality of first electrodes carried by the first paddle, and a guideline. The guideline has a distal section affixed to the first paddle and a proximal section having a length configured to extend externally of a patient. The second electrode unit has a dielectric second paddle and a plurality of second electrodes carried by the second paddle. The second paddle is configured to travel along the guideline and contact the first paddle in the side-by-side configuration. As a result, the first and second electrode units of this embodiment can be passed percutaneously through the same percutaneous entry hole and assembled in vivo at the stimulation site to form a larger paddle-type electrode array without surgical implantation.

Claims

1. An implantable neural stimulation electrode assembly, comprising:

a first electrode unit having a dielectric first paddle, a plurality of first electrodes carried by the first paddle, and a guideline having a distal section fixed to the first paddle and a proximal section having a length configured to extend externally of the patient; and

a second electrode unit having a dielectric second paddle and a plurality of second electrodes carried by the second paddle, wherein the second paddle is configured to travel along the guideline and be positioned adjacent to the first paddle in a side-by-side configuration within a patient.

2. The electrode assembly of claim 1 wherein the first electrode unit further comprises a deformable casing projecting from a side of the first paddle, and wherein a portion of the distal section of the guideline is encased within the casing.

3. The electrode assembly of claim 2 wherein the casing is configured to split apart as the second paddle advances distally adjacent to the first paddle.

4. The electrode assembly of claim 1 wherein second electrode unit further comprises a lumen configured to receive and slide over the guideline until the second paddle is adjacent the first paddle.

5. The electrode assembly of claim 4 wherein the first electrode unit further comprises a first connector and the second electrode unit further comprises a second connector, and wherein the first and second connectors are configured to engage each other when the second paddle is adjacent the first paddle.

6. The electrode assembly of claim 5 wherein the first connector comprises a first magnet and the second connector comprises a second magnet.

7. The electrode assembly of claim 5 wherein:

the first connector comprises a longitudinal opening along a side of the first paddle and a longitudinal cavity within the first paddle that is exposed to the longitudinal opening, and wherein the guideline extends longitudinally through the longitudinal cavity; and

the second connector comprises a neck projecting from a side of the second paddle and a bulbous portion projecting from the neck, and wherein the lumen of the second electrode unit extends longitudinally through the bulbous portion.

8. The electrode assembly of claim 1 wherein:

the first paddle comprises a first edge and a second edge, the guideline comprises a first guideline attached to the first paddle at the first edge and extending along the first edge, and the first electrode unit further comprises a first primary connector along the first edge, a second primary connector along the second edge, and a second guideline attached to the first paddle at the second edge and extending along the second edge;

the second electrode unit comprises a lumen through the second paddle configured to receive the first guideline and a first secondary connector configured to engaged the first primary connector such that the second paddle is adjacent to the first edge of the first paddle when implanted in a patient; and

the electrode assembly further comprises a third electrode unit having a dielectric third paddle, a plurality of third electrodes carried by the third paddle, a lumen through the third paddle configured to receive the second guideline, and a second secondary connector configured to engage the second primary connector such that the third paddle is adjacent to the second edge of the first paddle when implanted in a patient.

9. The electrode assembly of claim 8 wherein the first electrodes are cathodes and the second and third electrodes are anodes.

10. The electrode assembly of claim 1 wherein the distal section of the guideline is coupled to the first electrodes, the guideline is composed of an electrically conductive material, and the proximal section of the guideline has an electrical terminal configured to engage a pulse generator.

11. The electrode assembly of claim 1 wherein the first electrode unit further comprises a first channel configured to receive a stylet and/or a guidewire, the second electrode unit further comprises a lumen configured to receive and slide over the guideline, and the second electrode unit also comprises a second channel configured to receive the stylet and/or a guidewire.

12. The electrode assembly of claim 11 wherein the first electrode unit further comprises a flexible tip projecting distally from the first paddle and the first channel extends into the flexible tip.

13. An implantable neural stimulation electrode assembly, comprising:

a first electrode unit having a dielectric first paddle, first electrodes carried by the first paddle, a first electrical line having a distal portion connected to at least one of the first electrodes and a proximal portion extending proximally from the first paddle, and a guideline having a distal section attached to the first paddle and a proximal section extending proximally of the first paddle; and

a second electrode unit having a dielectric second paddle with a lumen and second electrodes carried by the second paddle, wherein the lumen is configured to receive and slide along the guideline such that the second electrode unit is adjacent to the first electrode unit when the second electrode unit is at the distal section of the guideline.

14. The electrode assembly of claim 13 wherein the first electrode unit further comprises a deformable casing projecting from a side of the first paddle, and wherein a portion of the distal section of the guideline is encased within the casing.

15. The electrode assembly of claim 14 wherein the casing is configured to split apart as the second paddle advances distally adjacent to the first paddle.

16. The electrode assembly of claim 13 wherein the first electrode unit further comprises a first connector and the second electrode unit further comprises a second connector, and wherein the first and second connectors are configured to engage each other when the second paddle is adjacent the first paddle.

17. The electrode assembly of claim 16 wherein the first connector comprises a first magnet and the second connector comprises a second.

18. The electrode assembly of claim 16 wherein:

the first connector comprises a longitudinal opening along a side of the first paddle and a longitudinal cavity within the first paddle that is exposed to the longitudinal opening, and wherein the guideline extends longitudinally through the longitudinal cavity; and

the second connector comprises a neck projecting from a side of the second paddle and a bulbous portion projecting from the neck, and wherein the lumen of the second electrode unit extends longitudinally through the bulbous portion.

19. The electrode assembly of claim 13 wherein:

the first paddle comprises a first edge and a second edge, the guideline comprises a first guideline attached to the first paddle at the first edge and extending along the first edge, and the first electrode unit further comprises a first primary connector along the first edge, a second primary connector along the second edge, and a second guideline attached to the first paddle at the second edge and extending along the second edge;

the second electrode unit comprises a lumen through the second paddle configured to receive the first guideline and a first secondary connector configured to engaged the first primary connector such that the second paddle is adjacent to the first edge of the first paddle when implanted in a patient; and

the electrode assembly further comprises a third electrode unit having a dielectric third paddle, a plurality of third electrodes carried by the third paddle, a lumen through the third paddle configured to receive the second guideline, and a second secondary connector configured to engage the second primary connector such that the third paddle is adjacent to the second edge of the first paddle when implanted in a patient.

20. An implantable neural stimulation electrode assembly, comprising:

a first electrode unit having a dielectric first support with a first contact surface and a first back surface, and a plurality of first electrodes at the first contact surface such that the first electrodes are electrically isolated from the first back surface; and

a second electrode unit having a dielectric second support with a second contact surface and a second back surface, and a plurality of second electrodes at the second contact surface of the second support such that the second electrodes are electrically isolated from the second back surface of the second support, wherein the second support is configured to engage the first support when implanted in a patient such that the first contact surface and the second contact surface face in a common direction.

21. The electrode assembly of claim 20 wherein:

the first support comprises a first paddle and the first electrode unit further comprises a guideline having a distal section attached to the first paddle and a proximal section; and

the second support comprises a second paddle having a lumen configured to receive and slide over the guideline such that the second paddle is adjacent to an edge of the first paddle when the second lumen is at the distal section of the guideline.

22. The electrode assembly of claim 21 wherein the first electrode unit further comprises a deformable casing projecting from the edge of the first paddle, and wherein a portion of the distal section of the guideline is encased within the casing.

23. The electrode assembly of claim 22 wherein the casing is configured to split apart as the second paddle advances distally adjacent to the first paddle.

24. The electrode assembly of claim 20 wherein the first electrode unit further comprises a first connector and the second electrode unit further comprises a second connector, and wherein the first and second connectors are configured to engage each other when the second electrode unit is adjacent the first electrode unit.

25. The electrode assembly of claim 24 wherein the first connector comprises a first magnet and the second connector comprises a second magnet in which the first and second magnets are attracted to each other.

26. The electrode assembly of claim 24 wherein:

the first connector comprises a longitudinal opening along a side of the first electrode unit and a longitudinal cavity within the first electrode unit that is exposed to the longitudinal opening, and wherein the guideline extends longitudinally through the longitudinal cavity; and

the second connector comprises a neck projecting from a side of the second electrode unit and a bulbous portion projecting from the neck, and wherein the lumen of the second electrode unit extends longitudinally through the bulbous portion.

27. The electrode assembly of claim 21 wherein:

the first paddle comprises a first edge and a second edge, the guideline comprises a first guideline attached to the first paddle at the first edge and extending along the first edge, and the first electrode unit further comprises a first primary connector along the first edge, a second primary connector along the second edge, and a second guideline attached to the first paddle at the second edge and extending along the second edge;

the second electrode unit comprises a lumen through the second paddle configured to receive the first guideline and a first secondary connector configured to engaged the first primary connector such that the second paddle is adjacent to the first edge of the first paddle when implanted in a patient; and

the electrode assembly further comprises a third electrode unit having a dielectric third paddle, a plurality of third electrodes carried by the third paddle, a lumen through the third paddle configured to receive the second guideline, and a second secondary connector configured to engage the second primary connector such that the third paddle is adjacent to the second edge of the first paddle when implanted in a patient.

28. A method of implanting a neural stimulation electrode assembly at a spinal cord of a patient, comprising:

percutaneously placing a distal portion of a percutaneous implanter in an epidural space at the spinal cord;

advancing a first electrode unit through the percutaneous implanter and into the epidural space, wherein the first electrode unit has guideline fixed to a portion of the first electrode unit and extending through the percutaneous implanter; and

sliding a second electrode unit along the guideline and into the epidural space such that the second electrode unit directly contacts the first electrode unit.

29. The method of claim 28 wherein the second electrode unit has a lumen and sliding the second electrode unit along the guideline comprises inserting the guideline into the lumen and moving the second electrode unit distally until the second electrode unit is adjacent to the first electrode unit.

30. The method of claim 29 wherein the first electrode unit further comprises a deformable casing projecting from a side of the first electrode unit and a portion of a distal section of the guideline is encased within the casing, and wherein sliding the second electrode unit along the guideline comprises moving the second electrode unit through the casing such that the casing engages an edge of the second electrode unit.

31. The method of claim 28 wherein the wherein the first electrode unit further comprises a first connector and the second electrode unit further comprises a second connector such that the first and second connectors are configured to engage each other when the second electrode unit is adjacent the first electrode unit, and wherein sliding the second electrode unit along the guideline further comprises engaging the first connector with the second connector.

32. The method of claim 31 wherein the first connector comprises a first magnet and the second connector comprises a second magnet, and wherein engaging the first connector with the second connector comprises attracting the first and second magnets together.

33. The method of claim 31 wherein:

the first connector comprises a longitudinal opening along a side of the first electrode unit and a longitudinal cavity within the first electrode unit that is exposed to the longitudinal opening, and wherein the guideline extends longitudinally through the longitudinal cavity;

the second connector comprises a neck projecting from a side of the second electrode unit and a bulbous portion projecting from the neck, and wherein the lumen of the second electrode unit extends longitudinally through the bulbous portion; and

sliding the second electrode unit along the guideline further comprises inserting the bulbous portion into the longitudinal cavity and positioning the neck in the longitudinal opening.

34. The method of claim 28 wherein the guideline comprises a first guideline extending from a first side of the first electrode unit and the first electrode unit further comprises a second guideline extending from a second side of the first electrode unit, sliding the second electrode unit along the guideline comprises sliding the second electrode unit over the first guideline until the second electrode unit is at the first side of the first electrode unit, and the method further comprises sliding a third electrode unit over the second guideline until the third electrode unit is at the second side of the first electrode unit.

35. The method of claim 34 wherein the first, second, and third electrode units are inserted sequentially into the patient through a common opening in the patient and the second and third electrode units are engaged with the first electrode unit in vivo.

36. The method of claim 34 wherein the first, second and third electrode units are positioned such that rows of the first, second and third electrodes are aligned in generally straight lines.

37. The method of claim 34 wherein the first electrode unit is staggered relative to the second and third electrode units.

38. A method of stimulating a spinal neural site of a patient, comprising:

percutaneously placing a distal portion of a percutaneous implanter in an epidural space at the spinal site;

advancing a first electrode unit through the percutaneous implanter and into the epidural space, wherein the first electrode unit has guideline fixed to a portion of the first electrode unit and extending through the percutaneous implanter;

sliding a second electrode unit along the guideline and into the epidural space such that the second electrode unit directly contacts the first electrode unit; and

delivering an electrical signal to the patient via at least one of the first and second electrode units.

39. The method of claim 38 wherein the second electrode unit has a lumen and sliding the second electrode unit along the guideline comprises inserting the guideline into the lumen and moving the second electrode unit distally until the second electrode unit is adjacent to the first electrode unit.

40. The method of claim 39 wherein the first electrode unit further comprises a deformable casing projecting from a side of the first electrode unit and a portion of a distal section of the guideline is encased within the casing, and wherein sliding the second electrode unit along the guideline comprises moving the second electrode unit through the casing such that the casing engages an edge of the second electrode unit.

41. The method of claim 39 wherein the wherein the first electrode unit further comprises a first connector and the second electrode unit further comprises a second connector such that the first and second connectors are configured to engage each other when the second electrode unit is adjacent the first electrode unit, and wherein sliding the second electrode unit along the guideline further comprises engaging the first connector with the second connector.

42. The method of claim 41 wherein the first connector comprises a first magnet and the second connector comprises a second magnet, and wherein engaging the first connector with the second connector comprises attracting the first and second magnets together.

43. The method of claim 41 wherein:

the first connector comprises a longitudinal opening along a side of the first electrode unit and a longitudinal cavity within the first electrode unit that is exposed to the longitudinal opening, and wherein the guideline extends longitudinally through the longitudinal cavity;

the second connector comprises a neck projecting from a side of the second electrode unit and a bulbous portion projecting from the neck, and wherein the lumen of the second electrode unit extends longitudinally through the bulbous portion; and

sliding the second electrode unit along the guideline further comprises inserting the bulbous portion into the longitudinal cavity and positioning the neck in the longitudinal opening.

44. The method of claim 38 wherein delivering an electrical signal to the patient comprises delivering a bipolar electrical field between first and second electrodes.

45. The method of claim 44 wherein the first electrodes are commonly biased.

46. The method of claim 44 wherein the first electrodes are biased independently of each other.

47. The method of claim 41 wherein the first and second electrode units are placed proximate to the dorsal root.

48. The method of claim 38 wherein the guideline comprises a first guideline extending from a first side of the first electrode unit and the first electrode unit further comprises a second guideline extending from a second side of the first electrode unit, sliding the second electrode unit along the guideline comprises sliding the second electrode unit over the first guideline until the second electrode unit is at the first side of the first electrode unit, and the method further comprises sliding a third electrode unit over the second guideline until the third electrode unit is at the second side of the first electrode unit.

49. The method of claim 48 further comprising biasing the first electrodes at one of a positive or negative polarity and biasing the second and third electrodes at the other of the positive or negative polarity to create a tripolar electrical field.

50. The method of claim 49 wherein the first electrode unit is placed at a medial area relative to the spinal cord, the second electrode unit is placed at least proximate to a left dorsal root, and the third electrode unit is placed at least proximate to a corresponding right dorsal root.

51. An implantable neural stimulation electrode assembly, comprising:

a first electrode unit having a dielectric first paddle, a plurality of first electrodes carried by the first paddle, and a guideline having a distal section fixed to the first paddle and a proximal section having a length configured to extend externally of the patient; and

a second electrode unit having a dielectric second paddle and a plurality of second electrodes carried by the second paddle, wherein the second paddle is configured to travel along the guideline and be positioned adjacent to the first paddle in a side-by-side configuration within a patient;

wherein the first paddle has a first support with a non-circular cross-sectional shape at the first electrodes, a flexible first distal tip with a circular cross-sectional shape, and a transition portion between the first support and the first distal tip; and

wherein the second paddle has a second support with a non-circular cross-sectional shape at the second electrodes, a flexible second distal tip with a circular cross-sectional shape, and a transition portion between the second support and the second distal tip.