Implant System and Delivery Method
Improved systems having flexible detachment zones provide myriad benefits for devices designed, for example, to emplace embolic coils. Downstream usages show enhanced clinical efficacy in terms of deliverability, conformability and microcatheter kickback—in addition to increasing first button electrolytic detachment consistency.
1 . An improved system for detaching vasoocclusive implants, comprising, in combination:
an elongate pushing member; and
at least a metallic coil structure having a zone of enhanced flexure and a first and second end, wherein the first (proximal) end is coupled to the elongate pushing member via a detachable zone.
2 . The system of claim 1 , wherein the reduction of stiffer glue bonding by at least about 50% in the zone of enhanced flexure within the detachment zone results in reduced proximal stiffness.
3 . The improved system of claim 2 , wherein said reduction of stiffer glue bonding within the zone of enhanced flexure is reduced from approximately 0.040″ (±0.20″) to at least about 0.020″ (±0.010″).
4 . The improved system of claim 3 , wherein the reduction in glue bond length by approximately half results in improved detachment and deliverability owing to the reduction in proximal stiffness.
5 . The improved system of claim 4 , wherein the reduction in glue bond length by approximately half results in more conformability of the system in difficult angled or tortuously constrained spaced with tight dimensions.
6 . The improved system of claim 5 , where the reduction in proximal stiffness results in less microcatheter kickback.
7 . The improved system of claim 6 , wherein the reduction in proximal stiffness increases first button detachment consistency, when electronic detachment is performed.
8 . A vasoocclusive implant designed for use with an improved detachment zone, which comprises, in combination:
a metallic coil having a first end and a second end and having an outer diameter between about 0.009″ and about 0.019″; and
a three-dimensional structure, formed from the metallic coil, the three-dimensional structure comprising a first loop having a first diameter and a second loop having a second diameter, the first and second loops generally arrayed along a first axis and spaced apart from each other by at least a dimension equal to the first diameter, a third loop having a third diameter and a fourth loop having a fourth diameter, the third and fourth loops generally arrayed along a second axis and spaced apart from each other by at least a dimension equal to the third diameter, a fifth loop having a fifth diameter and a sixth loop having a sixth diameter, the fifth and sixth loops generally arrayed along a third axis and spaced apart from each other by at least a dimension equal to the fifth diameter, wherein the first, second and third axes substantially approximate orthogonal lines, and wherein the sixth diameter is between about 60% and 80% of the diameter of each of the first through fifth loop diameters.
9 . The vasoocclusive implant of claim 8 , wherein the metallic coil is wound from wire having a circular cross-section.
10 . The vasoocclusive implant of claim 8 , wherein the metallic coil is wound from wire comprising a platinum alloy.
11 . The vasoocclusive implant of claim 10 , wherein the platinum alloy comprises about 8% tungsten.
12 . The vasoocclusive implant of claim 8 , wherein the first loop includes the first end of the metallic coil and the sixth loop includes the second end of the metallic coil.
13 . The vasoocclusive implant of claim 8 , wherein the sixth diameter is between about 67% and 73% of each of the first through fifth loop diameters.
14 . The vasoocclusive implant of claim 8 , wherein the three-dimensional structure approximates a spheroid.
15 . The vasoocclusive implant of claim 8 , wherein the elongate pushing member comprises a core wire and an outer coil surrounding the core wire, the outer coil having a proximal end and a distal end, and formed from radiodense material, the outer coil further having a larger pitch at its distal end than at its proximal end.
16 . The vasoocclusive implant of claim 10 , wherein a first outer diameter at the distal end of the outer coil is larger than a second outer diameter at the proximal end of the outer coil.
17 . The vasoocclusive implant of claim 15 , wherein the proximal end of the coil has sufficient radiopacity to serve as a fluoroscopic marker.
18 . The vasoocclusive implant of claim 15 , further comprising a polymeric tube which envelops substantially all of the outer coil and at least a portion of the core wire.
19 . The vasoocclusive implant of claim 8 , wherein the three-dimensional structure is configured to be inserted into an aneurysm for the purpose of embolization.
20 . An improved vascular implant system, further comprising:
a polymeric tubular member having a proximal end and a distal end, the polymeric tubular member surrounding the stainless steel wire proximal and adjacent to the electrolytically detachable zone, further comprising a zone of enhanced flexure where reduction of stiffer glue bonding section by 50% allows the flexibility of the system to be improved over existing systems.