Method of making a cochlear electrode array having current-focusing and tissue-treating features

• US 6,862,805 B1
• Filed: 08/31/2001
• Issued: 03/08/2005
• Est. Priority Date: 08/26/1998
• Status: Expired due to Term

• Current Assignee: Advanced Bionics AG (Sonova Holding AG)
• Original Assignee: Advanced Bionics Corporation (Sonova Holding AG)
• Inventors: Harrison, William Vanbrooks, Kuzma, Janusz A., Maltan, Albert A.
• Primary Examiner(s): Tugbang, A. Dexter
• Assistant Examiner(s): PHAN, THIEM D
• Application Number:
  US09/945,304
• Time in Patent Office: 1,285 Days
• Field of Search: 298/58, 298/25, 298/47, 298/54, 298/57, 298/60, 607/137
• US Class Current: 29/858
• CPC Class Codes: A61N 1/0541 Cochlear electrodes
• CPC Class Codes: Y10T 29/49117 Conductor or circuit manufacturing
• CPC Class Codes: Y10T 29/49156 with selective destruction of conductive paths
• CPC Class Codes: Y10T 29/49169 Assembling electrical component directly to terminal or elongated conductor
• CPC Class Codes: Y10T 29/49174 Assembling terminal to elongated conductor
• CPC Class Codes: Y10T 29/49176 with molding of electrically insulating material
• CPC Class Codes: Y10T 29/49179 by metal fusion bonding

Abstract

A method of making an implantable electrode array, adapted for insertion into a cochlea, includes the steps of: (a) forming electrode contact pieces made from a precious, biocompatible material into a desired shape; (b) attaching the electrode contact pieces to a foil sheet made from a non-toxic but chemically-active metal; (c) connecting a wiring system to the metal contact pieces; (d) molding a flexible polymer carrier around the electrode contact pieces and wiring system while such are held in place by the foil sheet; and (e) etching away the foil sheet, leaving the electrode contact pieces exposed at a surface of the molded polymer carrier. The exposed electrode contacts are made so as to have a shape, geometry, or makeup that aids in controlling the current flow and current density associated with the electrode contact as a function of position on the electrode contact.

Claims

1. A method of making an implantable electrode array comprising:

(a) forming electrode contact pieces made from a precious, biocompatible material into a desired shape;

(b) attaching the electrode contact pieces to a foil sheet made from a non-toxic but chemically-active metal,

(c) connecting a wiring system to the metal contact pieces;

(d) molding a flexible polymer carrier around the electrode contact pieces and wiring system while such are held in place by the foil sheet; and

(e) etching away the foil sheet, leaving the electrode contact pieces exposed at a surface of the molded polymer carrier.

2. The method of claim 1 wherein step (a) comprises forming the electrode contact pieces into an oval shape.

3. The method of claim 1 wherein step (a) comprises forming the electrode contact pieces into a star shape.

4. The method of claim 1 further comprising coating the electrode contact pieces exposed at a surface of the molded polymer carrier with a material that controls the surface impedance of the electrode contact piece as a function of location on the contact surface.

5. The method of claim 4 comprising coating each electrode contact piece so that the surface impedance of the contact piece increases as a function of distance from the center of the electrode contact piece.

6. The method of claim 1 further comprising masking an electrode contact piece exposed at a surface of the molded polymer carrier with an insulative mask that prevents conduction at various locations at the surface of the electrode contact piece.

7. The method of claim 1 further comprising coating at least one of the flexible polymer carrier or electrode contact piece with a drug compound selected to diffuse into tissue around the electrode array for the purpose of any one of the following:

inhibiting fibrous tissue growth, inhibiting bone growth, promoting healing, preventing neural degeneration, and promoting neural regeneration.

8. The method of claim 7 wherein the step of coating with a drug compound comprises coating at least one of the flexible center or electrode contact piece with a steroid.

9. The method of claim 7 wherein the step of coating with a drug compound comprises coating at least one of the flexible carrier or electrode contact piece with a neuro-trophin.

10. The method of claim 7 wherein step (c) comprises molding the flexible polymer carrier so that the resulting electrode array assumes a naturally curved shape.