Steerable catheter and method of making the same

1 . A steerable catheter comprising:

a helical coil of wire, the helical coil comprising an outer diameter; an inner diameter; a longitudinal axis; a distal end; a proximal end; and, a lumen extending longitudinally from the distal end to the proximal end, the helical coil having at least a first section of loosely coiled loops defining at least one gap;

a ribbon having a distal end and a proximal end, the ribbon extending longitudinally, adjacent to the longitudinal axis, within the lumen, from the distal end of the helical coil to the proximal end of the helical coil;

a tip comprising a laser-welded fusion of the distal end of the helical coil and the distal end of the ribbon, the tip being arranged to close the distal end of the helical coil, and having a diameter substantially equal to or less than the outer diameter of the helical coil, wherein the tip is operatively arranged to move in a first direction away from the longitudinal axis when the ribbon is forced in a first longitudinal direction, and move in a second direction away from the longitudinal axis when the ribbon is forced in a second longitudinal direction.

2 . The steerable catheter as recited in claim 1 wherein the helical coil is at least partially covered in a coating.

3 . The steerable catheter as recited in claim 1 wherein the helical coil and the ribbon both comprise stainless steel.

4 . The steerable catheter as recited in claim 1 wherein the tip is substantially spherical.

5 . The steerable catheter as recited in claim 1 wherein the wire has a substantially circular cross-section.

6 . A method of making a steerable catheter comprising:

providing a helical coil of wire of laser weldable material, the helical coil comprising a longitudinal axis, a distal end, a proximal end, and a lumen extending longitudinally from the distal end to the proximal end;

providing a ribbon of laser weldable material having a distal end and a proximal end, the ribbon extending longitudinally, adjacent to the longitudinal axis, within the lumen, from the distal end of the helical coil past the proximal end of the helical coil;

applying a first set of pulses from a laser welder to the distal end of the ribbon and the distal end of the helical coil, the first set of pulses being sufficient to generate a molten fusion of the distal end of the ribbon and the distal end of the helical coil; and,

applying a second set of pulses from a laser welder to the molten fusion sufficient to shape the molten fusion into a tip arranged to close the distal end of the helical coil.

7 . The method recited in claim 6 wherein both the helical coil and the ribbon comprise stainless steel.

8 . The method recited in claim 6 wherein the helical coil further comprises at least a first section of loosely coiled loops defining at least one gap, an outer diameter, and an inner diameter, wherein the tip has a diameter substantially equal to or less than the outer diameter of the helical coil.

9 . The method recited in claim 6 wherein the helical coil is at least partially covered in a coating comprising.

10 . The method recited in claim 6 wherein the tip is operatively arranged to move in a first direction away from the longitudinal axis when the ribbon is forced in a first longitudinal direction, and move in a second direction away from the longitudinal axis when the ribbon is forced in a second longitudinal direction.

11 . The method recited in claim 6 wherein the laser welder is a pulse Nd-YAG micro laser welder.

12 . The method catheter as recited in claim 6 wherein the tip is substantially spherical.

13 . The method as recited in claim 6 wherein the wire has a substantially circular cross-section.

14 . The steerable catheter made according to the method recited in claim 6 .

15 . A steerable catheter comprising:

a helical coil of wire, the helical coil comprising an outer diameter; an inner diameter; a longitudinal axis; a distal end; a proximal end; and, a lumen extending longitudinally from the distal end to the proximal end, the helical coil having at least a first section of loosely coiled loops defining at least one gap;

a ribbon having a distal end and a proximal end, the ribbon extending longitudinally, adjacent to the longitudinal axis, within the lumen, from the distal end of the helical coil substantially to the proximal end of the helical coil;

a tip formed by laser-welding the distal end of the helical coil and the distal end of the ribbon, the tip being arranged to close the distal end of the helical coil, and having a diameter substantially equal to or less than the outer diameter of the helical coil, wherein the tip is operatively arranged to move in a first direction away from the longitudinal axis when the ribbon is forced in a first longitudinal direction, and move in a second direction away from the longitudinal axis when the ribbon is forced in a second longitudinal direction.

16 . The steerable catheter as recited in claim 15 wherein the helical coil is at least partially covered in a coating.

17 . The steerable catheter as recited in claim 15 wherein the helical coil and the ribbon both comprise stainless steel.

18 . The steerable catheter as recited in claim 15 wherein the tip is substantially spherical.

19 . The steerable catheter as recited in claim 15 wherein the wire has a substantially circular cross-section.

20 . The steerable catheter as recited in claim 15 wherein the laser-welding is performed by a Nd-YAG laser welder.