Implantable electric terminal for organic tissue

• US 4,011,861 A
• Filed: 10/28/1975
• Issued: 03/15/1977
• Est. Priority Date: 04/03/1974
• Status: Expired due to Term

• Current Assignee: Case Western Reserve University
• Original Assignee: Case Western Reserve University
• Inventors: Enger, Carl C.
• Primary Examiner(s): Michell, Robert W.
• Assistant Examiner(s): Cohen, Lee S.
• Application Number:
  US05/626,191
• Time in Patent Office: 504 Days
• Field of Search: 128/418, 128/419 P, 128/419 B, 128/419 C, 128/419 D, 128/419 E, 128/419 F, 128/404, 128/2.06 E, 128/2.1 E, 128/DIG. 4, 3/1
• US Class Current: 600/377
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61N 1/04 Electrodes electrosurgical electrodes A61B18/14
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence

Abstract

A non-reacting implantable electric terminal for organic tissue, which is porous and intermeshes with the tissue including blood capillaries without the formation of a fibrous tissue encapsulation that reduces the sensitivity of tissue to electricity. This electric terminal is composed of tissue-compatible implantable material or materials at least one of which is electrically conductive, such as platinum, or an alloy, and which has on at least one surface thereof a porous material or layer having pores that are interconnected and continuous so that body electrolytes and/or tissue containing blood capillaries can contact the electrically conductive material through said porous material or layer. The pores of this material or layer also must have an average diameter sufficient to permit blood vessels to form in them, i.e. a diameter preferably between about 10 and 500 microns. This porous material may be either electrically conductive or electrically non-conductive, and may comprise a porous metal, carbon, ceramic, such as one containing aluminum oxide, and/or a synthetic polymer, or elastomer, such as one containing a silicone, a fluorocarbon, or an epoxy resin. The shape of the electric terminal may vary as desired, and the more interconnected pores it contains the better. This electric terminal may either be placed on the surface of the tissue like a plate or disk, or be inserted into the tissue.

Claims

1. A non-reacting implantable electric terminal for an organic tissue comprising:

an electrically conductive portion having a surface thereof adapted to contact tissue electrolyte, said surface being completely surrounded and in intimate contact with an inert non-absorbable porous material having interconnected and continuous pores of an average diameter of between 10 and 500 microns so as to permit ingress of blood capillaries and intermeshing with said tissue without the formation of a fibrous tissue interface adjacent said surrounding part, and to permit electrolytes in the tissue to pass therethrough and to be in continuous contact with said electrically conductive portion, and means for connecting the electrically conductive portion of said electric terminal to an electrical circuit means.

2. An electric terminal according to claim 1 wherein said electrically conductive portion and said porous material are compatible with said electrolytes and said tissue.

3. An electric terminal according to claim 1 wherein said electrically conductive portion is an implantable metal.

4. An electric terminal according to claim 1 wherein said porous material comprises a ceramic metallic oxide.

5. An electric terminal according to claim 4 wherein said porous ceramic comprises aluminum oxide.

6. An electric terminal according to claim 1 wherein said porous material comprises a plastic.

7. An electric terminal according to claim 6 wherein said porous plastic is an elastomer.

8. An electric terminal according to claim 1 wherein said porous material comprises a mixture of a ceramic and plastic material.

9. An electric terminal according to claim 1 wherein said porous material is between about 5% and 85% porous.

10. An electric terminal according to claim 1 wherein said electrically conductive portion is substantially completely surrounded by said porous material.

11. An electric terminal according to claim 1 wherein said porous material is electrically conductive.

12. An electric terminal according to claim 1 wherein said electrically conductive portion and said porous material have substantially the same chemical composition.

13. An electric terminal according to claim 1 wherein said porous material forms a layer on said electrically conductive portion.

14. An electric terminal according to claim 1 wherein said electrically conductive portion is porous.

15. An electric terminal according to claim 1 wherein said porous material including its pores are coated with an electrically conductive material.

16. A non-reacting electric terminal for contact with organic tissue, comprising:

a. a tissue compatible electrically conductive material having a surface thereof adapted to contact tissue electrolyte, and

b. a porous layer of a tissue compatible inert non-absorbable material completely surrounding and in intimate contact with said surface of said conductive material, wherein at least some pores are interconnected through the thickness of said layer and have an average diameter ranging between about 10 and 500 microns,

whereby blood vessels of said organic tissue can penetrate said pores without the formation of a fibrous tissue interface between said tissue and said materials adjacent said layer, and whereby electrolytes in said tissue can contact said electrically conductive material; and

c. means for connecting the electrically conductive material of said electric terminal to an electrical circuit means.

17. An electric terminal according to claim 16 wherein said electrically conductive material is an implantable metal.

18. An electric terminal according to claim 16 wherein said porous material comprises a ceramic metallic oxide.

19. An electric terminal according to claim 18 wherein said porous ceramic comprises aluminum oxide.

20. An electric terminal according to claim 16 wherein said porous material comprises a plastic.

21. An electric terminal according to claim 16 wherein said porous layer is between about 5% and 85% porous.

22. An electric terminal according to claim 16 wherein said electrically conductive material is substantially completely surrounded by said porous layer of tissue compatible material.

23. An electric terminal according to claim 16 wherein said porous layer of material is electrically conductive.

24. An electric terminal according to claim 16 wherein said electrically conductive material and said porous layer of tissue compatible material have substantially the same chemical composition.

25. An electric terminal according to claim 16 wherein said electrically conductive material is porous.

26. An electric terminal according to claim 16 wherein said porous layer including its pores are coated with an electrically conductive material.