Medical implant with piezoelectric material in contact with body tissue

• US 6,571,130 B1
• Filed: 10/20/2000
• Issued: 05/27/2003
• Est. Priority Date: 04/22/1998
• Status: Expired due to Fees

• Current Assignee: St. Jude Medical AB (Abbott Laboratories)
• Original Assignee: St. Jude Medical AB (Abbott Laboratories)
• Inventors: Nilsson, Kenth, Ljungström, Karin, Lidman, Johan, Kjellman, Charlotte
• Primary Examiner(s): Jastrzab, Jeffrey R.
• Application Number:
  US09/673,747
• Time in Patent Office: 949 Days
• Field of Search: 607/36, 607/116-122, 600/373-381
• US Class Current: 607/116
• CPC Class Codes: A61L 31/028 Other inorganic materials not covered by A61L31/022 - A61L31/026
• CPC Class Codes: A61N 1/0565 Electrode heads
• CPC Class Codes: C04B 35/495 based on vanadium, niobium, tantalum, molybdenum or tungsten oxides or solid solutions thereof with other oxides, e.g. vanadates, niobates, tantalates, molybdates or tungstates

Abstract

A medical implant has an element with at least a part thereof which is composed of piezoelectric material. The piezoelectric material is suitable for contact with body tissue and/or body fluids, and has the formula Na_xK_yNbO₃, with 0≦x≦0.8, 0.2≦y≦1, and x+y=1.

Claims

1. A medical implant comprising:

an element adapted for implantation in a living subject, said element having at least one part adapted for contact with tissue of said living subject; and

said at least one part composed of piezoelectric material adapted for contact with tissue of said living subject; and

said piezoelectric material comprising Na_xK_yNbO₃, wherein 0≦

x≦

0.8, 0.2≦

y≦

1, and x+y=1.

2. A medical implant as claimed in claim 1 wherein 0.2≦

x≦

0.8 and 0.2≦

y≦

0.8.

3. A medical implant as claimed in claim 1 wherein 0.4≦

x≦

0.6 and 0.4≦

y≦

0.6.

4. A medical implant as claimed in claim 1 wherein x=y=0.5.

5. A medical implant as claimed in claim 1 wherein said piezoelectric material has a relative density exceeding 97%.

6. A medical implant as claimed in claim 1 wherein said piezoelectric material has a pore size of less than 4 μ

m.

7. A medical implant as claimed in claim 1 wherein said piezoelectric material has a grain size of less than 4 μ

m.

8. A medical implant as claimed in claim 1 wherein said piezoelectric material has a piezoelectric constant d₃₃ exceeding 100 pCN⁻

.

9. A medical implant as claimed in claim 1 wherein said element is an electrode lead, and wherein said part composed of piezoelectric material is a piezoelectric electrode carried by said electrode lead for electrically stimulating said tissue.

10. A medical implant as claimed in claim 9 further comprising a tissue stimulator connected to said electrode lead.

11. A medical implant as claimed in claim 1 wherein said element is an electrode lead, and wherein said part composed of piezoelectric material is a sensor for sensing physiological variables in said tissue.

12. A medical implant as claimed in claim 11 further comprising a tissue stimulator connected to said electrode lead.

13. A medical implant as claimed in claim 1 wherein said element is an electrode lead, and wherein said part composed of piezoelectric material is a piezoelectric electrode for participating in stimulation of said tissue and sensing of physiological variables in said tissue.

14. A medical implant as claimed in claim 13 further comprising a tissue stimulator connected to said electrode lead.