Aneurysm treatment coils
Systems and devices for endovascular treatment of intracranial aneurysms are described. Various configurations of coiled implants may be used as stenting devices or aneurysm coils. The implants include one or more filaments wound about a longitudinal axis to form a generally tubular shape. Lateral flexibility of the implants may be manipulated by, for example, adjusting a pitch between adjacent filaments, using different materials for the filaments, employing different filament cross-sectional shapes, grouping filaments into pluralities of varying flexibilities, and nesting inner coils within outer coils.
1. A coiled implant, comprising:
an outer coil arranged in a first winding formed by a first filament, the first winding having a circular or oval winding shape in a cross section transverse to a longitudinal axis of the implant; and
an inner coil concentric within the outer coil and arranged in a second winding formed by a second filament, the second winding having a polygonal winding shape in a cross section transverse to the longitudinal axis;
wherein the outer coil comprises the first filament and a third filament, and wherein a diameter of the first filament varies from a diameter of the third filament.
2. The coil of claim 1 , wherein a direction of the first winding and a direction of the second winding direction are opposite.
3. The coil of claim 1 , wherein the polygonal shape is triangular or rectangular.
4. The coil of claim 1 , wherein a rotational orientation of the inner coil winding shape varies along a long axis of the inner coil.
5. The coil of claim 1 , wherein a first region of the implant has a first flexibility permitting bending at the first region in a first direction relative to the long axis, the first flexibility being greater than a second flexibility permitting bending, in the first direction, of a second region of the implant that is spaced apart from the first region along a long axis of the implant.
6. The coiled implant of claim 1 , wherein a pitch of the inner coil is at least twice a pitch of the outer coil.
7. The coiled implant of claim 6 , wherein a pitch of the inner coil is at least four times a pitch of the outer coil.
8. A coiled implant, comprising:
an outer coil arranged in a first winding formed by a first filament, the first winding having a first polygonal winding shape in a cross section transverse to a longitudinal axis of the implant; and
an inner coil concentric within the outer coil and arranged in a second winding formed by a second filament, the second winding having a second polygonal winding shape in a cross section transverse to the longitudinal axis;
wherein the outer coil comprises the first filament and a third filament, and wherein a diameter of the first filament varies from a diameter of the third filament.
9. The coil of claim 8 , wherein a direction of the first winding and a direction of the second winding direction are opposite.
10. The coil of claim 8 , wherein at least one of the first and second polygonal shapes is triangular or rectangular.
11. The coil of claim 8 , wherein a rotational orientation of the inner coil winding shape varies along a longitudinal axis of the inner coil.
12. The coil of claim 8 , wherein a first region of the implant has a first flexibility permitting bending at the first region in a first direction relative to the long axis, the first flexibility being greater than a second flexibility permitting bending, in the first direction, of a second region of the implant that is spaced apart from the first region along a long axis of the implant.
13. The coil of claim 8 , wherein the first and second shapes are the same.
14. The coil of claim 8 , wherein the first polygonal winding shape is different from the second polygonal winding shape.
15. The coiled implant of claim 8 , wherein a pitch of the inner coil is at least twice a pitch of the outer coil.
16. The coiled implant of claim 15 , wherein a pitch of the inner coil is at least four times a pitch of the outer coil.