Flexible electrode assembly having variable pitch electrodes for a stimulating medical device

• US 20070135885A1
• Filed: 11/30/2006
• Published: 06/14/2007
• Est. Priority Date: 12/08/2005
• Status: Active Grant

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Risi, Frank
• Granted Patent: US 7,881,811 B2
• Time in Patent Office: Days
• US Class Current: 607/137
• CPC Class Codes: A61N 1/0541 Cochlear electrodes

Abstract

An electrode assembly for use in a prosthetic hearing implant, the electrode assembly comprising: an elongate carrier member for implantation into the cochlea, the carrier member having a proximal end adapted to be positioned in a basal region of the cochlea, and a distal end adapted to be positioned in an apical region of the cochlea; and a plurality of electrodes disposed along a longitudinal surface of the carrier member, wherein the plurality of electrodes have a predetermined spacing to attain a desired flexibility along the length of the carrier member.

Claims

1. An electrode assembly for use in a prosthetic hearing implant, comprising:

an elongate carrier member for implantation into the cochlea, the carrier member having a proximal end adapted to be positioned in a basal region of the cochlea, and a distal end adapted to be positioned in an apical region of the cochlea; and

a plurality of electrodes disposed along a longitudinal surface of said carrier member, wherein said plurality of electrodes have a predetermined spacing to attain a desired flexibility along said length of said carrier member.

2. The electrode assembly of claim 1, further comprising:

a stiffening member embedded in at least a proximal region of carrier member, wherein said stiffening member has a malleability that varies longitudinally along a length of said stiffening member.

3. The electrode assembly of claim 1, wherein said variable spacing of said plurality of electrodes and said variable malleability are selected to achieve a desired flexibility along the length of said carrier member.

4. The electrode assembly of claim 1, further comprising:

a laterally-extending collar member connected to said proximal end of said carrier member and configured to abut the cochlea when said carrier member is implanted at said maximum insertion depth, and to prevent further insertion of said carrier member into the cochlea.

5. The electrode assembly of claim 1, wherein said carrier member is longitudinally-tapered, wherein said proximal end of said carrier member has greater dimensions than said distal end of said carrier member.

6. The electrode assembly of claim 4, further comprising:

a band circumferentially surrounding said proximal end of said carrier member, said band formed of a material that produces a tissue reaction that facilitates tissue attachment to the band.

7. The electrode assembly of claim 1, wherein said carrier member has opposing medial and lateral longitudinal surfaces, wherein when implanted, said medial surface faces toward the center of the cochlea and said lateral surface that faces toward the exterior of the cochlea, wherein said electrode assembly further comprises:

a tapered tip region disposed at said distal end of said carrier member, wherein said tip region comprises a distal end having a radius of curvature, wherein said tip region slopes from said curved distal end toward said proximal end of said carrier member, and sloping upward from said curved distal end toward said lateral surface.

8. The electrode assembly of claim 4, further comprising:

a holding member having a distal end connected to said proximal end of said collar member, wherein said holding member is configured to provide a surface for manual control of said electrode assembly.

9. The electrode assembly of claim 4, further comprising:

an elongate lead connected to said proximal end of said collar member, said lead physically and electrically connecting said electrode assembly an implanted stimulator unit.

10. The electrode assembly of claim 9, wherein said lead is continuous with no intermediate electrical connectors between said electrode assembly and the stimulator unit.

11. The electrode assembly of claim 1, wherein said plurality of electrodes are positioned along said carrier member so as to align with predetermined regions of a tonotopically mapped cochlea.

12. The electrode assembly of claim 1, wherein said carrier member has opposing medial and lateral longitudinal surfaces, wherein when implanted, said medial surface faces toward the center of the cochlea and said lateral surface that faces toward the exterior of the cochlea,

wherein at least one of said plurality of electrodes has a surface that is collocated with said medial surface of said carrier member.

13. The electrode assembly of claim 1, wherein each of said plurality of electrodes is electrically connected to at least one multi- or single-filament wire embedded within said carrier member.

14. The electrode assembly of claim 13, wherein said wires are embedded in a volumetric core of said carrier member.

15. The electrode assembly of claim 13, wherein said wires are located at or near surfaces of said carrier member.

16. The electrode assembly of claim 15, wherein said wires are located in different regions of said carrier member to facilitate curvature or to maintain orientation of said carrier member once said carrier member is implanted.

17. An electrode assembly for use in a prosthetic hearing implant, comprising:

an elongate carrier member for implantation into the cochlea, the carrier member having a proximal end adapted to be positioned in a basal region of the cochlea, and a distal end adapted to be positioned in an apical region of the cochlea; and

a plurality of electrodes disposed along a longitudinal surface of said carrier member, wherein a pitch of said plurality of electrodes varies over at least one portion of said elongate carrier member to attain a desired carrier member flexibility along said length of said carrier member.

18. The electrode assembly of claim 17, further comprising:

a stiffening member embedded in at least a proximal region of carrier member, wherein said stiffening member has a malleability that varies longitudinally along a length of said stiffening member.

19. The electrode assembly of claim 18, wherein said variable pitch of said plurality of electrodes and said variable malleability of said stiffening member are selected to achieve a desired flexibility along the length of said carrier member.

20. The electrode assembly of claim 17, further comprising:

a laterally-extending collar member connected to said proximal end of said carrier member and configured to abut the cochlea when said carrier member is implanted at said maximum insertion depth, and to prevent further insertion of said carrier member into the cochlea.

21. The electrode assembly of claim 17, wherein said carrier member is longitudinally-tapered, wherein said proximal end of said carrier member has greater dimensions than said distal end of said carrier member.

22. The electrode assembly of claim 20, further comprising:

a band circumferentially surrounding said proximal end of said carrier member, said band formed of a material that produces a tissue reaction that facilitates tissue attachment to the band.

23. The electrode assembly of claim 17, wherein said carrier member has opposing medial and lateral longitudinal surfaces, wherein when implanted, said medial surface faces toward the center of the cochlea and said lateral surface that faces toward the exterior of the cochlea, wherein said electrode assembly further comprises:

a tapered tip region disposed at said distal end of said carrier member, wherein said tip region comprises a distal end having a radius of curvature, wherein said tip region slopes from said curved distal end toward said proximal end of said carrier member, and sloping upward from said curved distal end toward said lateral surface.

24. The electrode assembly of claim 20, further comprising:

a holding member having a distal end connected to said proximal end of said collar member, wherein said holding member is configured to provide a surface for manual control of said electrode assembly.

25. The electrode assembly of claim 20, further comprising:

an elongate lead connected to said proximal end of said collar member, said lead physically and electrically connecting said electrode assembly an implanted stimulator unit.

26. The electrode assembly of claim 25, wherein said lead is continuous with no intermediate electrical connectors between said electrode assembly and the stimulator unit.

27. The electrode assembly of claim 17, wherein said plurality of electrodes are positioned along said carrier member so as to align with predetermined regions of a tonotopically mapped cochlea.

28. The electrode assembly of claim 17, wherein said carrier member has opposing medial and lateral longitudinal surfaces, wherein when implanted, said medial surface faces toward the center of the cochlea and said lateral surface that faces toward the exterior of the cochlea,

wherein at least one of said plurality of electrodes has a surface that is collocated with said medial surface of said carrier member.

29. The electrode assembly of claim 17, wherein each of said plurality of electrodes is electrically connected to at least one multi- or single-filament wire embedded within said carrier member.

30. The electrode assembly of claim 29, wherein said wires are embedded in a volumetric core of said carrier member.

31. The electrode assembly of claim 29, wherein said wires are located at or near surfaces of said carrier member.

32. The electrode assembly of claim 31, wherein said wires are located in different regions of said carrier member to facilitate curvature or to maintain orientation of said carrier member once said carrier member is implanted.