Laminated electrode for a cochlear implant

• US 20040172118A1
• Filed: 03/24/2004
• Published: 09/02/2004
• Est. Priority Date: 03/29/2001
• Status: Active Grant

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Gibson, Peter
• Granted Patent: US 7,406,352 B2
• Time in Patent Office: Days
• US Class Current: 607/137
• CPC Class Codes: A61N 1/0541 Cochlear electrodes

Abstract

An implantable cochlear implant electrode array (30) that can adopt a first, preferably straight, configuration selected to allow the array to be inserted into the cochlea and at least a second, preferably, spirally curved, configuration wherein the electrode array (30) is adapted to apply tissue stimulation. The electrode array (30) comprises an elongate carrier (31) having a proximal end (37), a distal end (34), and a plurality of electrodes supported by the carrier (31) at respective spaced locations thereon, the carrier (31) is formed, preferably moulded, to preferentially adopt the second configuration or another configuration different to said first configuration. The outer layer (33) is releasably connected to the elongate carrier (31) by an adhesive layer (32) and is formed so as to bias the carrier (31) into the first configuration when connected thereto. A method of forming the electrode array (30) is also disclosed.

Claims

1. An implantable electrode array that can adopt a first configuration selected to allow the array to be inserted into an implantee'"'"'s body and at least a second configuration wherein said electrode array is adapted to apply tissue stimulation, the array comprising:

an elongate carrier having a proximal end and a distal end, a plurality of electrodes supported by the carrier at respective spaced locations thereon in a region between the proximal end and the distal end, the carrier being formed to preferentially adopt the second configuration or another configuration different to said first configuration; and

an outer layer releasably connected to the elongate carrier, the outer layer being formed so as to bias the carrier into the first configuration when connected thereto.

2. An implantable electrode array of claim 1 wherein the implantable electrode array is a cochlear implant electrode array insertable into the cochlea of an implantee.

3. An implantable electrode array of claim 1 wherein the elongate carrier has an inner surface that is substantially conformable, following implantation, with the inner wall of the cochlea.

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

5. An implantable electrode array of claim 2 wherein the outer layer has a length that extends from the proximal end to the distal end of the carrier.

6. An implantable electrode array of claim 2 wherein the first configuration is at least substantially straight and the second configuration is at least substantially spirally curved.

7. An implantable electrode array of claim 6 wherein a straightening stylet extends through the outer layer to at least substantially straighten the outer layer and hence the electrode array into the first configuration.

8. An implantable electrode array of claim 6 wherein the outer layer is reinforced with one or more reinforcing ribs to maintain the outer layer and hence the electrode array in a substantially straight first configuration.

9. An implantable electrode array of claim 6 wherein the outer layer is moulded with a preferential curvature opposite to the preferential curvature of the carrier thereby resulting in the electrode array having the substantially straight first configuration.

10. An implantable electrode array of claim 2 wherein the carrier and the outer layer are each formed from a biocompatible elastomeric material.

11. An implantable electrode array of claim 2 wherein the outer layer is releasably connected to the carrier by a layer of bioresorbable adhesive.

12. An implantable electrode array of claim 11 wherein the adhesive layer is formed from a bioresorbable material that softens or dissolves on exposure to a body fluid of the implantee.

13. An implantable electrode array of claim 12 wherein, following implantation, the carrier subtends an angle of at least about 360°

.

14. An implantable electrode array of claim 12 wherein the bioresorbable material of the adhesive layer is selected from the group consisting of polyacrylic acid (PM), polyvinyl alcohol (PVA), polylactic acid (PLA), and polyglycolic acid (PGA).

22. A method of inserting an implantable electrode array in a cochlea of an implantee comprising the steps of:

(i) performing a cochleostomy;

(ii) inserting the electrode array of claim 6 through the cochleostomy; and

(iii) closing the cochleostomy.

23. A method of inserting an implantable electrode array in a cochlea of an implantee of claim 22 wherein during step (ii) the adhesive layer bonding the outer layer and carrier gradually dissolves thereby allowing the carrier to move towards its second configuration.

24. A method of inserting an implantable electrode array in a cochlea of an implantee of claim 22 wherein following insertion of the electrode array, and at least partial dissolution of the adhesive layer, the outer layer is withdrawn from the cochlea.

15. A method of forming an implantable electrode array that can adopt a first configuration selected to allow the array to be inserted into an implantee'"'"'s body and at least a second configuration wherein said electrode array is adapted to apply tissue stimulation, the method comprising the steps of:

(i) moulding an elongate carrier in a curved configuration in a first mould from a resiliently flexible material about an 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;

(ii) separately moulding at least an outer layer of the array in a second mould from a resiliently flexible material, the outer layer being moulded in a substantially straight or straight configuration;

(iii) removing the elongate carrier and the outer layer from the respective first and second moulds; and

(iv) straightening the carrier member and removably adhering it to the outer layer using a bioresorbable adhesive.

16. A method of forming an implantable electrode array of claim 15 wherein the electrode array is insertable into the cochlea of an implantee.

17. A method of forming an implantable electrode array of claim 16 wherein the first mould used to mould the carrier is spiral-shaped such that the carrier, following its manufacture and removal from the first mould, subtends an arc of about 450°

or greater

18. A method of forming an implantable electrode array of claim 16 wherein the second mould used to mould the outer layer is substantially straight or straight such that the outer layer, following its manufacture and removal from the second mould, is substantially straight or straight, respectively.

19. A method of forming an implantable electrode array of claim 18 wherein once the carrier is cured, the carrier is removed from the first mould and straightened in a straightening jig.

20. A method of forming an implantable electrode array of claim 19 wherein once the outer layer is cured, the outer layer is removed from the second mould and adhered to the carrier being held in the straightening jig.

21. A method of forming an implantable electrode array of claim 20 wherein once the outer layer is adhered to the carrier, the electrode array formed by this process is removed from the jig and packaged.