Multi-electrode catheter spine and method of making the same
A flexible frame comprising an electrically conductive hollow cylindrical metallic tube having a plurality of cuts along the longitudinal axis to form a plurality of conductive wires. The wires are equally spaced apart circumferentially along the longitudinal axis of the tube by a gap to electrically isolate the wires. A first electrode is mounted around the circumference of the frame along the longitudinal axis and attached to a first wire of the plurality of wires. A second electrode is mounted around the circumference of the flexible frame along the longitudinal axis at a predetermined distance from the first electrode and attached to a second wire. A non-conductive thermoplastic layer may be secured to the outer surface of the flexible frame between the first and second electrodes to form an insulation layer between the first and second electrodes.
1. An electrically conductive flexible frame comprising:
an electrically conductive hollow cylindrical metallic tube having an outer surface, a circumference and a longitudinal axis, the cylindrical metallic tube having a plurality of cuts along the longitudinal axis to form the flexible frame comprising a plurality of parallel conductive wires, the plurality of parallel conductive wires remaining parallel along the entire longitudinal axis of the cylindrical metallic tube, each of the plurality of conductive wires being equally spaced apart circumferentially along the longitudinal axis of the tube by a gap to electrically isolate the plurality of wires;
a first electrode mounted around the circumference of the flexible frame along the longitudinal axis of the tube and attached to a first wire of the plurality of conductive wires;
a second electrode mounted around the circumference of the flexible frame along the longitudinal axis of the tube at a predetermined distance from the first electrode and attached to a second wire of the plurality of conductive wires, the second wire being adjacent to the first wire and not attached to the first wire; and
a non-conductive thermoplastic layer secured to the outer surface of the flexible frame between the first and second electrodes, such that the thermoplastic layer circumferentially surrounds the plurality of conductive wires to form an insulation layer between the first and second electrodes.
2. The frame of claim 1 , wherein each of the plurality of conductive wires includes a non-conductive electrical insulator coating.
3. The frame of claim 2 , wherein the electrical insulator coating comprises parylene.
4. The frame of claim 1 , wherein the thermoplastic layer comprises a polyether block amide.
5. The frame of claim 1 , wherein the thermoplastic layer comprises a reflowed thermoplastic, wherein the reflowed thermoplastic fills each of the gaps between the plurality of conductive wires.
6. The frame of claim 1 , wherein the cylindrical metallic tube comprises a conductive metal chosen from the group consisting of nickel titanium alloy, stainless steel, platinum and MP35N alloy.
7. The frame of claim 1 , wherein the electrodes comprise an electrically conductive metal chosen from the group consisting of palladium, platinum, gold, iridium and combinations and alloys thereof.
8. The frame of claim 1 , wherein the number of the plurality of parallel conductive wires is between 8 and 50.
9. The frame of claim 1 , wherein each of the plurality of conductive wires has a width between 50 and 250 microns.
10. The frame of claim 1 , wherein each of the plurality of conductive wires has a width of approximately 20 microns.
11. The frame of claim 1 , wherein the first electrode includes a first keyhole for attaching the first electrode to the first wire of the plurality of conductive wires and the second electrode includes a second keyhole for attaching the second electrode to the second wire of the plurality of conductive wires.
12. The frame of claim 11 , wherein the first electrode is attached to the first wire of the plurality of conductive wires by a first weld through the first keyhole in the first electrode and the second electrode is attached to the second wire of the plurality of conductive wires by a second weld through the second keyhole in the second electrode.
13. The frame of claim 1 , wherein the plurality of cuts of the cylindrical metallic tube along the longitudinal axis are made by laser cutting.
14. A method of manufacturing an electrically conductive flexible frame, the method comprising:
cutting an electrically conductive hollow cylindrical metallic tube along a longitudinal axis of the tube to form a plurality of cuts along the longitudinal axis, the plurality of cuts forming the flexible frame comprising a plurality of parallel conductive wires, the plurality of parallel conductive wires remaining parallel along the entire longitudinal axis of the cylindrical metallic tube, each of the plurality of conductive wires being equally spaced apart circumferentially along the longitudinal axis of the tube by a gap to electrically isolate the plurality of conductive wires;
attaching a first electrode around the circumference of the flexible frame along the longitudinal axis of the tube to a first wire of the plurality of conductive wires;
attaching a second electrode around the circumference of the flexible frame along the longitudinal axis of the tube to a second wire of the plurality of conductive wires, the second wire being adjacent to the first wire and the second electrode being located a predetermined distance from the first electrode along the longitudinal axis of the tube and not attached to the first conductive wire;
forming a non-conductive thermoplastic layer on at least an outer surface of the flexible frame between the first and second electrodes, such that the thermoplastic layer circumferentially surrounds the plurality of conductive wires to form an insulation layer between the first and second electrodes.
15. The method of claim 14 , further comprising coating the plurality of conductive wires with a non-conductive coating.
16. The method of claim 15 , wherein the non-conductive coating comprises parylene.
17. The method of claim 14 , wherein the cylindrical metallic tube comprises a metal chosen from the group consisting of nickel titanium alloy, stainless steel, platinum and MP35N alloy.
18. The method of claim 14 , wherein forming the non-conducting thermoplastic layer comprises:
placing a thermoplastic tubing around the circumference of the flexible frame in between the first and second electrodes;
covering the thermoplastic tubing with a heat shrink tubing;
heating the thermoplastic tubing to reflow the thermoplastic tubing to form an outer layer.
19. The method of claim 18 , wherein the thermoplastic tubing is heated to reflow the thermoplastic tubing into the plurality of gaps between the plurality of wires to electrically isolate a plurality of conductive wires.
20. The method of claim 18 , wherein the thermoplastic tubing is heated to reflow the thermoplastic tubing to form a thermoplastic layer on the outer surface of the flexible frame.
21. The method of claim 14 , wherein the first electrode includes a first keyhole for attaching the first electrode to the first wire of the plurality of wires and the second electrode includes a second keyhole for attaching the second electrode to the second wire of the plurality of wires.
22. The method of claim 21 , wherein the first electrode is attached to the first wire of the plurality of conductive wires by welding through the keyhole in the first electrode and the second electrode is attached to the second wire of the plurality of conductive wires by welding through the keyhole in the second electrode.
23. The method of claim 14 , wherein the plurality of cuts of the cylindrical metallic tube along the longitudinal axis are made by laser cutting.