Helical electrode for nerve stimulation
View Patent ↗A helical electrode for nerve stimulation includes an insulative helical substrate, having an inner surface, configured to wrap around a nerve. An electrical conductor is disposed upon the inner surface of the substrate. The conductor defines a helix of about one revolution and produces an electric field in which an injected current in similar axons varies by no more than about 25%. The conductor may include tapered end sections, which may be counter-tapered.
1. A helical electrode for nerve stimulation, comprising:
an insulative helical substrate having an inner surface, the insulative helical substrate configured to wrap around a nerve; and
an electrical conductor disposed upon the inner surface, the electrical conductor having a first end portion, a second end portion opposite the first end portion, and a middle portion between the first end portion and the second end portion, the middle portion having a middle width, the electrical conductor defining a helix of about one revolution, the helix of about one revolution forming an overlap area where at least a portion of the first end portion and the second end portion longitudinally overlap, wherein the first end portion narrows from the middle width to a first width in a first direction away from the middle portion and the second end portion narrows from the middle width to a second width in a second direction away from the middle portion.
2. The helical electrode in accordance with claim 1 , wherein the electrical conductor is further configured to produce an electric field in which a first injected current varies by no more than about 10% from a second injected current.
3. The helical electrode in accordance with claim 1 , wherein the first width and the second width have similar width.
4. The helical electrode in accordance with claim 1 , wherein the first width and the second width have different widths.
5. The helical electrode in accordance with claim 1 , wherein the first end portion and the second end portion are counter-tapered.
6. The helical electrode in accordance with claim 1 , wherein each taper comprises about one fourth a length of the conductor, and reduces a width of the conductor by about ⅛.
7. The helical electrode in accordance with claim 1 , wherein the electrical conductor comprises truncated end sections.
8. The helical electrode in accordance with claim 1 , wherein the substrate defines the helix having a pitch of about 1 mm/turn to about 2.5 mm/turn and a central insulation aperture having a diameter from about 2 mm to about 3 mm.
9. The helical electrode in accordance with claim 1 , wherein the electrical conductor is a material including at least one of platinum, platinum/iridium alloy, iridium oxide, titanium nitride, tantalum and tantalum oxide.
10. The helical electrode in accordance with claim 1 , wherein the electrical conductor defines the helix of more than one revolution before implantation which accommodates for post-implantation expansion of the nerve.
11. The helical electrode in accordance with claim 1 , wherein the electrical conductor defines the helix of about 330° to about 375° after implantation.
12. A helical electrode for nerve stimulation, comprising:
an insulative helical substrate having an inner surface, the insulative helical substrate configured to wrap around substantially an entire circumference of a nerve,
wherein an entire circumference of the insulative helical substrate is divided into a plurality of equal sectors; and
an electrical conductor disposed upon the inner surface, the electrical conductor defining a helix of about one revolution, the electrical conductor configured to produce an electric field via an energy source in which a peak value of a second spatial derivative of the electric field applied in each of the plurality of equal sectors varies by no more than about 25%.
13. The helical electrode in accordance with claim 12 , wherein the electrical conductor is further configured to produce the electric field in which the peak value of the second spatial derivative of the electric field applied in each of the plurality of equal sectors varies by no more than about 10%.
14. The helical electrode in accordance with claim 12 , wherein the electrical conductor further comprises tapered end sections.
15. The helical electrode in accordance with claim 14 , wherein the tapered end sections are counter-tapered.
16. The helical electrode in accordance with claim 14 , wherein each taper comprises about one fourth a length of the electrical conductor and reduces a width of the electrical conductor by about ⅛.
17. The helical electrode in accordance with claim 12 , wherein the substrate defines the helix having a pitch of about 1 mm/turn to about 2.5 mm/turn and a central insulation aperture having a diameter from about 2 mm to about 3 mm.
18. The helical electrode in accordance with claim 12 , wherein the electrical conductor defines the helix of about 330° to about 375° after implantation.
19. A helical electrode for nerve stimulation, comprising:
an insulative helical substrate having an inner surface, the insulative helical substrate configured to wrap around a nerve; and
an electrical conductor characterized by a length and a width and disposed upon the inner surface so as to be adjacent to the nerve, the electrical conductor defining a helix of about one revolution, the electrical conductor having a middle section of uniform width and end sections that taper to a width narrower than the uniform width of the middle section.
20. The helical electrode in accordance with claim 19 , wherein the tapered end sections are counter-tapered such that a longitudinal distance between extreme edges of opposing ends of the electrical conductor is reduced.