Needle having multiple electrodes

• US 20050261602A1
• Filed: 05/17/2005
• Published: 11/24/2005
• Est. Priority Date: 05/18/2004
• Status: Active Grant

• Current Assignee: Natus Medical Incorporated
• Original Assignee: Excel-Tech Ltd. (Natus Medical Incorporated)
• Inventors: Kurtz, Ronald Leon, Mumford, John Robert
• Granted Patent: US 7,283,866 B2
• Time in Patent Office: Days
• US Class Current: 600/546
• CPC Class Codes: A61B 2562/125 characterised by the manufacture of electrodes
• CPC Class Codes: A61B 5/296 for electromyography [EMG]
• CPC Class Codes: A61B 5/6848 Needles
• CPC Class Codes: Y10T 29/49002 Electrical device making
• CPC Class Codes: Y10T 29/53204 Electrode

Abstract

Embodiments of the invention generally relate to needles having more than one electrode and which are particularly suited for use in electromyography. One embodiment relates to a tripolar needle having three concentric electrodes. The tripolar needle is formed by providing a needle blank having first and second concentric electrodes and forming a third concentric electrode around the needle blank. The tripolar needle has an outer diameter which is substantially constant along the shaft of the needle, except at the tip, where the needle is sharpened.

Claims

1. A needle for electrophysiological measurement having a distal sharpened tip portion and a shaft, the needle comprising:

first, second and third concentrically arranged electrodes;

first and second insulation layers for separating the first and second electrodes and the second and third electrodes, respectively; and

wherein the shaft has a substantially constant outer diameter proximally of and adjacent to a distal tip portion of the needle and wherein the third electrode at least partly defines the outer diameter of the shaft proximally of and adjacent to the distal tip portion.

2. The needle of claim 1, wherein the first, second and third electrodes are respective active, reference and ground electrodes during electromyography.

3. The needle of claim 1, wherein the third electrode is at least partially exposed along a substantial length of the shaft.

4. The needle of claim 3, wherein the first and second concentric electrodes are at least partially exposed in the tip portion.

5. The needle of claim 4, wherein the tip portion is substantially conically shaped.

6. The needle of claim 4, wherein the tip portion is substantially frustoconically shaped.

7. The needle of claim 4, wherein the tip portion is beveled.

8. The needle of claim 1, wherein an outer diameter of the needle is between 0.3 millimeters to 0.65 millimeters.

9. The needle of claim 1, wherein the outer diameter of the third electrode is substantially the same as an outer-most diameter of the needle.

10. A method of forming a needle, comprising:

providing a needle blank having first and second concentric electrodes;

providing an insulation material around at least part of the needle blank;

providing a conductive material around at least part of the insulation material to form a third electrode; and

sharpening one end of the needle blank to form a sharpened tip portion of the needle.

11. The method of claim 10, wherein the conductive material is plated or coated on the outside of the insulation material.

12. The method of claim 10, wherein the conductive material comprises a conductive sheath of a substantially tubular form.

13. The method of claim 10, further comprising the step of removing a portion of the second electrode before providing the insulation material.

14. The method of claim 10, wherein the step of sharpening provides a substantially conical or frusto-conical shape at the one end of the needle.

15. The method of claim 10, wherein the step of sharpening provides a beveled tip shape at the one end of the needle.

16. The method of claim 10, wherein the third electrode is formed along a shaft portion of the needle, proximally of the tip portion.

17. The method of claim 10, wherein the needle is formed so that an outer diameter of the third electrode is substantially the same as an outermost diameter of the needle blank, which is substantially the same as an outermost diameter of the needle.

18. A method of forming a needle, comprising:

providing a needle blank having first and second concentric electrodes;

providing a conductive material around at least part of the needle blank;

injecting an insulating material between the needle blank and the conductive material; and

sharpening one end of the needle blank to form a sharpened tip portion of the needle.

19. The method of claim 18, wherein the conductive material comprises a conductive sheath of a substantially tubular form.

20. A method of forming a needle, comprising:

providing a needle blank having first and second concentric electrodes;

forming an outer insulation layer around the needle blank;

forming a third concentric electrode around the outer insulation layer; and

sharpening one end of the needle blank to form a sharpened tip portion of the needle.

21. The method of claim 20, further comprising the step of removing some of the outer insulation layer and some of the third electrode so that an outermost diameter of the needle is substantially constant along a shaft of the needle.

22. The method of claim 21, wherein the outermost diameter of the needle is between 0.3 mm and 0.65 mm.

23. The method of claim 20, wherein the third electrode is formed along a shaft portion of the needle, proximally of and adjacent to the tip portion.

24. The method of claim 21, wherein the needle is formed so that an outer diameter of the third electrode is substantially the same as an outermost diameter of the needle blank, which is substantially the same as the outermost diameter of the needle.

25. The method of claim 20, wherein the third electrode is plated or coated on the outside of the insulation layer.

26. The method of claim 20, wherein the third electrode comprises a conductive sheath of a substantially tubular form.

27. The method of claim 21, further comprising the step of removing a portion of the second electrode before forming the outer insulation layer.

28. The method of claim 20, wherein the step of sharpening provides a beveled tip shape at the one end of the needle.

29. The method of claim 20, wherein the step of sharpening provides a substantially conical or frustroconical tip shape at the one end of the needle.

30. The method of claim 29, wherein the tip is sharpened so that the first and second electrodes have respective exposed portions on the tip separated by a substantially constant gap.

31. A method of forming a needle, comprising the steps of;

providing a needle blank having first and second concentric electrodes, the first electrode being formed inwardly of the second electrode;

removing a portion of the second electrode along a shaft of the needle;

adding an insulation layer around the needle at least along the part of the shaft from which the portion of the second electrode was removed;

providing a conductive material to form a conductive layer around the insulation layer;

cutting excess added insulation material and conductive material from the needle so that an outer diameter of the needle is the same as an outer diameter of the needle blank, whereby a third concentric electrode is formed from the conductor layer at least partly along the portion of the shaft from which the portion of the second electrode was removed; and

sharpening one end of the needle blank to form a sharpened tip portion of the needle.