Delivery and detachment systems and methods for vascular implants
A system for delivering an implant device to a vascular site in a patient a delivery pusher apparatus, an implant device detachably connected to the delivery pusher apparatus by a tether having a distal end connected to a proximal end of the implant device, wherein the tether is substantially non-tensioned when connecting the implant device to the delivery pusher, and an electrical heating element configured coaxially around at least a portion of the tether, wherein heat generated by the heating element severs the tether at a point near the proximal end of the implant device.
1. An implant delivery system comprising:
a delivery pusher;
an implant device detachably connected to the delivery pusher by a tether having a distal end connected to a proximal end of the implant device, wherein the tether is substantially non-tensioned when connecting the implant device to the delivery pusher; and
an electrical heating element comprising:
an electric coil arranged coaxially around at least a portion of the tether and having a heat-generating zone, the coil being operable to achieve a temperature in the heat-generating zone that is sufficient to sever the tether, the electric coil comprising a first plurality of windings having a first pitch and a second plurality of windings having a second pitch that is greater than the first pitch;
wherein the first plurality of windings are in a first winding zone, and the second plurality of windings are in a second winding zone located distally from the first winding zone.
2. The implant delivery system of claim 1 , wherein the electric coil further comprises:
a third plurality of windings having a third pitch and a fourth plurality of windings having a fourth pitch that is greater than the third pitch.
3. The implant delivery system of claim 2 , wherein the second winding zone has a first portion and a second portion located distally from the first winding zone, the third plurality of windings are in a third winding zone located distally from the second winding zone, and the fourth plurality of windings are in a fourth winding zone located between the first and second portions of the second winding zone.
4. The implant delivery system of claim 3 , wherein the first portion of the second winding zone includes a single winding layer and the second portion of the second winding zone has a double winding layer.
5. The implant delivery system of claim 1 , wherein the heat-generating zone has between 2 and 10 coil windings.
6. The implant deliver system of claim 1 , wherein the heat-generating zone has a length that is between 0.1 mm and 0.5 mm.
7. The implant delivery system of claim 1 , wherein the tether is made of a material selected from a group consisting of one or more of polypropylene, polyamide, ethylene vinyl alcohol, polyethylene, polyolefin elastomer, and poly-paraphenyleneterepthalamide.
8. The implant delivery system of claim 1 , wherein the implant device includes a braided vascular occlusion device.
9. The implant delivery system of claim 1 , wherein the heating element is connectable to a power source by a pair of lead wires, wherein the heating element has a first resistance and the lead wires have a second resistance, and wherein the ratio of the first resistance to the second resistance is between 0.6 and 1.6.
10. An implant delivery system, comprising:
a delivery pusher;
an implant device;
a tether detachably connecting the implant device to the delivery pusher, wherein the tether is in a substantially linear, non-tensioned configuration when it is connecting the implant device to the delivery pusher; and
a heating element comprising:
an electric coil having a heat-generating zone, the coil being operable to achieve a temperature in the heat-generating zone that is sufficient to sever the tether, the coil arranged coaxially about the tether and operable to sever the tether when energized, the electric coil comprising a first plurality of windings having a first pitch and a second plurality of windings having a second pitch that is greater than the first pitch;
wherein the first plurality of windings are in a first winding zone, and the second plurality of windings are in a second winding zone located distally from the first winding zone.
11. The implant delivery system of claim 10 , wherein the electric coil further comprises:
a third plurality of windings having a third pitch and a fourth plurality of windings having a fourth pitch that is greater than the third pitch.
12. The implant delivery system of claim 11 , wherein the second winding zone has a first portion and a second portion located distally from the first winding zone, the third plurality of windings are in a third winding zone located distally from the second winding zone, and the fourth plurality of windings are in a fourth winding zone located between the first and second portions of the second winding zone.
13. The implant delivery system of claim 12 , wherein the first portion of the second winding zone includes a single winding layer and the second portion of the second winding zone has a double winding layer.
14. The implant delivery system of claim 10 , wherein the heat-generating zone has between 2 and 10 coil windings.
15. The implant deliver system of claim 10 , wherein the heat-generating zone has a length that is between 0.1 mm and 0.5 mm.
16. The implant delivery system of claim 10 , wherein the tether is made of a material selected from a group consisting of one or more of polypropylene, polyamide, ethylene vinyl alcohol, polyethylene, polyolefin elastomer, and poly-paraphenyleneterepthalamide.
17. The implant delivery system of claim 10 , wherein the implant device includes a braided vascular occlusion device.
18. The implant delivery system of claim 10 , wherein the heating element is connectable to a power source by a pair of lead wires, wherein the heating element has a first resistance and the lead wires have a second resistance, and wherein the ratio of the first resistance to the second resistance is between 0.6 and 1.6.