Three element coaxial vaso-occlusive device

A vaso-occlusive device, comprising:

• an elongate, flexible, filamentous microcoil inner element;
• an intermediate element coaxially surrounding the inner element and in intimate contact therewith and formed essentially of an expansile polymer capable of expanding at a controlled rate to fill an aneurysm;
• and
• a substantially non-expansile outer element coaxially surrounding the intermediate element and in intimate contact therewith, the outer element defining a gaps or opening through which the intermediate element is exposed;
• wherein the intermediate element, when expanded, protrudes through the gap or opening in the outer element and assumes a configuration with an undulating, convexly-curved outer surface defining a chain of arcuate segments, each having a diameter significantly greater than the diameter of the outer element.

A vaso-occlusive device, comprising:

• an elongate, flexible, filamentous inner element;
• a non-metallic expansile intermediate element coaxially surrounding the inner element and in intimate contact therewith, said expansile intermediate element capable of expanding at a controlled rate to fill an aneurysm;
• and
• an outer element coaxially surrounding the intermediate element and in intimate contact therewith, the outer element defining a gap or opening through which the intermediate element is exposed;
• wherein the inner element has proximal and distal ends, and wherein the outer element comprises an open-wound helical coil portion extending between proximal and distal end sections that are respectively attached to the inner element adjacent to the proximal and distal ends of the inner element, wherein the open-wound portion defines the gap or opening.

A vaso-occlusive device comprising:

• an open-coiled element;
• a expansile element capable of expanding at a controlled rate to fill an aneurysm and having a first state and a second state wherein:
• in said first state said expansile element does not extend through openings between coils of the open-coiled element;
• in said second state said expansile element is expanded through said openings between said coils of the open-coiled element.