An embolic coil comprises an elongated core element formed of a shape memory material treated to define a memorized secondary coil shape and an elongated outer element wound around the elongated core element to define a primary coil shape of the embolic coil. A method of forming an embolic coil, comprises the steps of imparting a memorized shape to a core element formed of a shape memory material, wherein the memorized shape defines a secondary coil of the embolic coil and straightening the core element in combination with the steps of winding an elongated outer element around the straightened core element to form a primary coil of the embolic coil and releasing the straightened core element when the device has been positioned at a deployment location to form the secondary coil of the embolic coil.
1. An embolic coil comprising:
an elongated core element formed of a shape memory material and movable between a straightened first configuration and a shape memorized second coiled configuration;
an elongated outer element which, in the first configuration, is wound around the elongated core element to form a primary coil; and
a plurality of fibers frictionally gripped by and between adjacent coils of the primary coil.
2. The embolic coil according to claim 1 , wherein the shape memory material is formed at an operational temperature of the embolic coil in an austenitic phase.
3. The embolic coil according to claim 1 , wherein the memorized shape of the elongated core element is substantially a coil.
4. The embolic coil according to claim 1 , wherein the memorized shape of the elongated core element is substantially a three dimensional spiral.
5. The embolic coil according to claim 1 , wherein the shape memory material of which the elongated core element is formed includes Nitinol.
6. The embolic coil according to claim 1 , wherein the elongated outer element is formed of platinum.
7. The embolic coil according to claim 1 , wherein the primary coil shape is a substantially cylindrical coil.
8. The embolic coil according to claim 1 , further comprising a plurality of fiber retention grooves formed on the elongated core element.
9. The embolic coil according to claim 1 , wherein the elongated outer element comprises a platinum wire co-wound with a wire formed of a shape memory material.
10. A coiled medical device for implantation in a patient comprising:
a primary coil having a primary coil shape, the primary coil defining a lumen extending therethrough;
a secondary coil formed of a shape memory material and disposed in the lumen, the secondary coil having a secondary coil memorized shape, wherein, when heated to a temperature above a critical temperature of the shape memory material, the secondary coil causes the primary coil to follow the secondary coil shape; and
a plurality of fibers gripped by and between adjacent coils of the primary coil and held therebetween by friction.
11. The medical device according to claim 10 , wherein the shape memory material includes Nitinol.
12. An embolic coil comprising:
an elongated core element formed of a shape memory material treated to define a memorized secondary coil shape, the elongated core including a plurality of fiber retention grooves formed in an outer surface thereof;
an elongated outer element wound around the elongated core element to define a primary coil shape of the embolic coil; and
a plurality of fibers held within the fiber retention grooves.
13. The embolic coil of claim 12 , wherein the fiber retention grooves extend circumferentially about the elongated core element.
14. The embolic coil of claim 12 , wherein the fiber retention grooves extend about the elongated core element along a spiral path.