Insertion tool for a cochlear implant electrode array

• US 7,894,916 B2
• Filed: 10/17/2001
• Issued: 02/22/2011
• Est. Priority Date: 10/17/2000
• Status: Expired due to Fees

• Current Assignee: Cochlear Limited
• Original Assignee: Cochlear Limited
• Inventors: Gibson, Peter, Treaba, Claudiu, Darley, Ian, Parker, John, Dadd, Fysh
• Primary Examiner(s): Patel; Niketa I
• Assistant Examiner(s): ALTER, ALYSSA MARGO
• Application Number:
  US10/203,079
• Publication Number:
  US 20030093139A1
• Time in Patent Office: 3,415 Days
• Field of Search: 607/137, 607/57, 607/56, 607/55
• US Class Current: 607/137
• CPC Class Codes: A61F 11/20 Ear surgery
• CPC Class Codes: A61N 1/0541 Cochlear electrodes

Abstract

A cochlear implant electrode assembly device (10) comprising an elongate electrode carrier member (11), and a shape element (15) formed of a memory material, such as Nitinol. The elongate member (11) is made of a resiliently flexible first material and has a length and a plurality of electrodes (12) mounted thereon adapted to apply a preselected tissue stimulation. The elongate member (11) has a pre-formed curved orientation that at least substantially matches an inside surface of a cochlea, an implantable orientation different to said pre-formed orientation that allows said member to be inserted into an implantee'"'"'s cochlea, and an at least one intermediate orientation between said implantable orientation and said pre-formed orientation. The shape element (15) is removably positioned within the elongate member (11) and extends along at least a portion of the length thereof. The shape element (15) has a first shape selected for biasing the elongate member (11) into the implantable orientation when the shape element is at a first temperature, and at least a second shape that allows the elongate member (11) to adopt said at least one intermediate orientation when the shape element (15) is exposed to a temperature of the cochlea (30) being different than the first temperature.

Claims

1. A cochlear implant comprising:

an elongate shape element configured to maintain a substantially straight configuration when at a first temperature and to curl in response to being at a second temperature greater than the first temperature; and

a resiliently flexible elongate carrier member, having a longitudinally-extending lumen configured to receive the shape element and a plurality of tissue-stimulating electrodes, configured to adopt substantially straight and partially curved configurations in response to biasing forces applied by said shape element positioned in said lumen when said shape element is at said first and second temperatures, respectively, and to adopt a fully curved configuration, in which said carrier member is configured to substantially conform to a modiolus when positioned in a cochlea, in response to said shape element being removed from said lumen;

wherein said shape element is configured to prevent said carrier member from adopting said fully curved configuration when said shape element is at a temperature approximately equal to body temperature and is positioned in said lumen; and

wherein, for said carrier member, said fully curved configuration is more curved than said partially curved configuration, and said partially curved configuration is more curved than said substantially straight configuration.

2. The cochlear implant of claim 1, wherein said elongate carrier member is formed of a first material, and wherein said shape element is formed of a shape memory material that is relatively stiffer than said first material.

3. The cochlear implant of claim 2, wherein said shape memory material comprises at least one plastic material.

4. The cochlear implant of claim 3, wherein said shape memory material is Nitinol.

5. The cochlear implant of claim 1, wherein said second temperature is approximately equal to body temperature.

6. The cochlear implant of claim 1, wherein said elongate carrier member is preformed from a biocompatible plastic material.

7. The cochlear implant of claim 6, wherein said biocompatible plastic material is selected from the group comprising a silicone, and a polyurethane.

8. The cochlear implant of claim 1, wherein said lumen extends through a substantial portion of said elongate carrier member from an opening at a proximal end of said carrier member to a distal end of said carrier member.

9. The cochlear implant of claim 1, wherein said shape element is configured to extend out from said elongate carrier member, when said shape element is disposed in said lumen, allowing said shape element to be manipulated and removed from said carrier member during insertion of said carrier member.

10. The cochlear implant of claim 1, wherein said plurality of tissue-stimulating electrodes are mounted along a surface of said elongate carrier member configured to face the modiolus when the carrier member is inserted in the cochlea.

11. The cochlear implant of claim 1, wherein said elongate carrier member further comprises an outer layer configured to act as a stiffening sheath for said carrier member.

12. The cochlear implant of claim 11, wherein said stiffening sheath is formed of a bioresorbable material configured to dissolve or soften on exposure to a fluid.

13. The cochlear implant of claim 12, wherein said bioresorbable material is selected from the group comprising polyacrylic acid (PAA), polyvinyl alcohol (PVA), polylactic acid (PLA) and polyglycolic acid (PGA).

14. The cochlear implant of claim 12, wherein the cochlear implant further comprises:

an additional layer surrounding said stiffening sheath configured to have a first rate of fluid ingress therethrough; and

at least one opening formed in said additional layer having a rate of fluid ingress therethrough that is greater than said first rate of fluid ingress through said additional layer.

15. The cochlear implant of claim 14, wherein said at least one opening in said additional layer is constructed and arranged to be closable so as to substantially prevent fluid ingress therethrough.

16. The cochlear implant of claim 1, wherein at least a portion of an outer surface of said elongate carrier member has a coating of a lubricious material.

17. The cochlear implant of claim 16, wherein said lubricious material is selected from the group comprising polyacrylic acid (PAA), polyvinyl alcohol (PVA), polylactic acid (PLA) and polyglycolic acid (PGA).

18. The cochlear implant of claim 1, wherein a resiliently flexible tip member extends forwardly from a distal end of said elongate carrier member.

19. The cochlear implant of claim 18, wherein said tip member has a plurality of metallic particles dispersed therethrough.

20. An implantable medical device comprising:

a cochlear implant comprising;

an elongate shape element configured to maintain a substantially straight configuration when at a first temperature and to curl in response to being at a second temperature greater than the first temperature; and

a resiliently flexible elongate carrier member, having a longitudinally-extending lumen configured to receive the shape element and a plurality of tissue-stimulating electrodes, configured to adopt substantially straight and partially curved configurations in response to biasing forces applied by said shape element positioned in said lumen when said shape element is at said first and second temperatures, respectively, and to adopt a fully curved configuration, in which said carrier member is configured to substantially conform to a modiolus when positioned in a cochlea, in response to said shape element being removed from said lumen;

wherein said shape element is configured to prevent said carrier member from adopting said fully curved configuration when said shape element is at a temperature approximately equal to body temperature and is positioned in said lumen; and

wherein, for said carrier member, said fully curved configuration is more curved than said partially curved configuration, and said partially curved configuration is more curved than said substantially straight configuration.

21. The implantable medical device of claim 20, wherein said elongate carrier member is formed of a first material, and wherein said shape element is formed of a shape memory material that is relatively stiffer than said first material.

22. The implantable medical device of claim 21, wherein said shape memory material comprises at least one plastic material.

23. The implantable medical device of claim 22, wherein said shape memory material is Nitinol.

24. The implantable medical device of claim 20, wherein said second temperature is approximately equal to body temperature.

25. The implantable medical device of claim 20, wherein said elongate carrier member is preformed from a biocompatible plastic material.

26. The implantable medical device of claim 25, wherein said biocompatible plastic material is selected from the group comprising a silicone, and a polyurethane.

27. The implantable medical device of claim 20, wherein said lumen extends through a substantial portion of said elongate carrier member from an opening at a proximal end of said carrier member to a distal end of said carrier member.

28. The implantable medical device of claim 20, wherein said shape element is configured to extend out from said elongate carrier member, when said shape element is disposed in said lumen, allowing said shape element to be manipulated and removed from said carrier member during insertion of said carrier member.

29. The implantable medical device of claim 20, wherein said plurality of tissue-stimulating electrodes are mounted along a surface of said elongate carrier member configured to face the modiolus when the carrier member is inserted in the cochlea.

30. The implantable medical device of claim 20, wherein said elongate carrier member further comprises an outer layer configured to act as a stiffening sheath for said carrier member.

31. The implantable medical device of claim 30, wherein said stiffening sheath is formed of a bioresorbable material configured to dissolve or soften on exposure to a fluid.

32. The implantable medical device of claim 31, wherein said bioresorbable material is selected from the group comprising polyacrylic acid (PAA), polyvinyl alcohol (PVA), polylactic acid (PLA) and polyglycolic acid (PGA).

33. The implantable medical device of claim 31, wherein the cochlear implant further comprises:

an additional layer surrounding said stiffening sheath configured to have a first rate of fluid ingress therethrough; and

at least one opening formed in said additional layer having a rate of fluid ingress therethrough that is greater than said first rate of fluid ingress through said additional layer.

34. The implantable medical device of claim 33, wherein said at least one opening in said additional layer is constructed and arranged to be closable so as to substantially prevent fluid ingress therethough.

35. The implantable medical device of claim 20, wherein at least a portion of an outer surface of said elongate carrier member has a coating of a lubricious material.

36. The implantable medical device of claim 35, wherein said lubricious material is selected from the group comprising polyacrylic acid (PAA), polyvinyl alcohol (PVA), polylactic acid (PLA) and polyglycolic acid (PGA).

37. The implantable medical device of claim 20, wherein a resiliently flexible tip member extends forwardly from a distal end of said elongate carrier member.

38. The implantable medical device of claim 37, wherein said tip member has a plurality of metallic particles dispersed therethrough.

39. A method for implanting a resiliently flexible carrier member of a cochlear implant into a recipient'"'"'s cochlea, the carrier member having a longitudinally-extending lumen configured to receive an elongate shape element and a plurality of tissue-stimulating electrodes, the shape element configured to maintain a substantially straight configuration when at a first temperature and to curl in response to being at a second temperature greater than the first temperature, the method comprising:

maintaining the shape element at a first temperature when the shape element is positioned in the lumen to maintain the carrier member in a substantially straight configuration;

inserting the carrier member into the recipient'"'"'s cochlea while the shape element is positioned in the lumen thereby exposing the shape element to a temperature greater than the first temperature and approximately equal to body temperature and thereby causing the shape element to bias the carrier member into a partially curved configuration that is more curved than the substantially straight configuration;

preventing the carrier member from adopting a fully curved configuration that is more curved than the partially curved configuration via the shape element positioned in the lumen when the shape element is at the temperature approximately equal to body temperature; and

removing the shape element from the lumen thereby allowing the carrier member to adopt the fully curved configuration, and thereby allowing the carrier member to substantially conform to a modiolus of the cochlea.