Pre-curved cochlear implant electrode array

• US 20040030376A1
• Filed: 07/09/2003
• Published: 02/12/2004
• Est. Priority Date: 11/29/2000
• Status: Active Grant

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Gibson, Peter, Treaba, Claudiu, Parker, John, Dadd, Fysh
• Granted Patent: US 7,451,000 B2
• Time in Patent Office: Days
• US Class Current: 607/137
• CPC Class Codes: A61F 11/20 Ear surgery
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: B28B 5/00 Producing shaped articles from the material in moulds or on moulding surfaces, carried or formed by, in or on conveyors irrespective of the manner of shaping

Abstract

An implantable electrode array (30) that can adopt a first configuration selected to allow the array (30) to be inserted into a cochlea (12) of an implantee and at least a second configuration in which the array can apply tissue stimulation. The array (30) comprises an elongate carrier (31) having a proximal end (37), a distal end (34), and an inner surface (35) conformable with the inner wall of the implantee'"'"'s cochlea (12). A plurality of electrodes (36) are supported within the carrier (31) at respective spaced locations thereon in a region between the proximal end (37) and the distal end (34) with at least one of the electrodes having a surface that is at least adjacent the inner surface (35) of the carrier (31). The carrier (31) is formed in the second configuration from a first layer (32) and at least a second layer (32) of resiliently flexible material. A method of forming an array (30) is also described.

Claims

1. An implantable electrode array that can adopt a first configuration selected to allow the array to be inserted into a cochlea of an implantee and at least a second configuration in which the array can apply tissue stimulation, the array comprising:

an elongate carrier having a proximal end, a distal end, and an inner surface conformable with the inner wall of the implantee'"'"'s cochlea; and

a plurality of electrodes supported within the carrier at respective spaced locations thereon in a region between the proximal end and the distal end, at least one of the electrodes having a surface that is at least adjacent the inner surface of the carrier;

wherein the carrier is formed in said second configuration from a first layer and at least a second layer of resiliently flexible material.

2. An implantable electrode array of claim 1 wherein each of the electrodes in the array have a surface that is at least adjacent the inner surface of the carrier.

3. An implantable electrode array of claim 2 wherein the surfaces of the electrodes are aligned with the inner surface of the carrier.

4. An implantable electrode array of claim 1 wherein the first layer overlies each of the electrodes except their said respective surfaces at least adjacent the inner surface of the carrier.

5. An implantable electrode array of claim 1 wherein the first layer extends from the proximal end to the distal end of the carrier.

6. An implantable electrode array of claim 5 wherein the second layer extends from the proximal end to the distal end of the carrier and overlies the entire outer surface of the first layer.

7. An implantable electrode array of claim 1 wherein the first layer and second layer are formed from different materials.

8. An implantable electrode array of claim 1 wherein the first and second layers are formed from the same material.

9. An implantable electrode array of claim 8 wherein the first and second layers are each formed from a biocompatible silicone rubber.

10. An implantable electrode array of claim 1 wherein the thickness of the first layer between its inner surface and outer surface is substantially constant for at least a majority of its length from the proximal end to the distal end.

11. An implantable electrode array of claim 1 wherein the thickness of the first layer decreases from the proximal end to the distal end.

12. An implantable electrode array of claim 11 wherein the thickness of the second layer decreases from the proximal end to the distal end.

13. An implantable electrode array of claim 1 wherein the second configuration comprises a spiral configuration.

14. An implantable electrode array of claim 1 wherein the carrier has a lumen extending longitudinally from an opening at the proximal end into the carrier and adapted to receive a stiffening element that is sized to fit into the lumen and extend substantially through the carrier to bias the carrier into the first configuration in which the carrier is insertable into the cochlea of the implantee.

15. An implantable electrode array of claim 14 wherein the first configuration is straight or substantially straight.

16. An implantable electrode array of claim 1 wherein at least a portion of the outer surface of the carrier has a coating of a material that becomes lubricious on being brought into contact with a fluid, said material being selected from the group consisting of polyacrylic acid (PAA), polyvinyl alcohol (PVA), polylactic acid (PLA) and polyglycolic acid (PGA).

17. A method of manufacturing an implantable electrode array, the method comprising the steps of:

(i) moulding a first layer of an elongated carrier from a resiliently flexible material about a longitudinal array of electrodes such that at least one of the electrodes has a surface that is at least adjacent an inner surface of the carrier; and

(ii) moulding a second layer of the carrier from a resiliently flexible material over at least a portion of the surface of the first layer other than its inner surface.

18. A method of manufacturing an implantable electrode array of claim 17 wherein the array of electrodes is formed by positioning a series of platinum rings on or about a removable longitudinal support.

19. A method of manufacturing an implantable electrode array of claim 18 wherein the support comprises a wire coated with a relatively low-friction material.

20. A method of manufacturing an implantable electrode array of claim 19 wherein once positioned about the wire, a series of electrically conducting wires are welded to each of the electrodes.

21. A method of manufacturing an implantable electrode array of claim 20 wherein the first layer is moulded in a first spiral-shaped mould.

22. A method of manufacturing an implantable electrode array of claim 21 wherein the spiral-shaped mould subtends an arc of greater than about 720°

.

23. A method of manufacturing an implantable electrode array of claim 22 wherein the first layer, once cured, is removed from the first mould and placed in a second mould having a set of dimensions greater than the first mould.

24. A method of manufacturing an implantable electrode array of claim 23 wherein the second mould comprises a spiral-shaped mould having at least an inner surface and which subtends an arc less than that of the first mould.

25. A method of manufacturing an implantable electrode array of claim 24 wherein the second mould subtends an arc of about 180°

less than the arc subtended by the first mould.

26. A method of manufacturing an implantable electrode array of claim 25 wherein on placement of the first layer in the second mould, the inner surface of the first layer abuts with the inner surface of the second mould.

27. A method of manufacturing an implantable electrode array of claim 26 wherein once the second layer is cured, the carrier is removed from the second mould and straightened.

28. A method of manufacturing an implantable electrode array of claim 27 wherein once the carrier is straightened, the wire is removed from within the carrier so leaving a lumen within the first layer of the carrier.

29. A method of manufacturing an implantable electrode array of claim 28 wherein while the carrier is held at least substantially straight, a straightening element is inserted into the lumen to hold the carrier in the straightened configuration until such time as the carrier is to be inserted into a cochlea.

30. An implantable electrode array when formed using the method of any one of claims 17 to 29.

31. An implantable electrode array for insertion into the cochlea of an implantee, said array comprising:

a first layer made of a resiliently flexible material and supporting a plurality of electrodes within said first layer with at least one of said electrodes having a surface that is at least adjacent the inner surface of the first layer, said first layer being of a curved configuration;

at least a second layer made of resiliently flexible material and overlaying an outer surface of the first layer, said at least second layer also being of a curved configuration;

wherein the plurality of layers together form a pre-curved electrode carrier capable of applying tissue stimulation.

32. An implantable electrode array of claim 31 wherein the degree of curvature of the first layer is greater than that of the at least second layer.

33. An implantable electrode array of claim 31 wherein the degree of curvature of the electrode carrier can be controlled by altering one or both of the degrees of curvature of the first and at least second layers.

34. An implantable electrode array of claim 31 wherein each of the electrodes in the first layer have a surface that is at least adjacent the inner surface of the carrier.

35. An implantable electrode array for insertion into the cochlea of an implantee, said array comprising:

a first layer made of a resiliently flexible material and having a curved configuration and a first degree of curvature;

at least a second layer made of a resiliently flexible material and having a curved configuration and a second degree of curvature;

wherein the layers in combination form an electrode array having a degree of curvature dependent on the respective degrees of curvature of the first layer and the at least second layer.

36. An implantable electrode array of claim 35 wherein the first layer has a greater degree of curvature than the at least second layer.