Vasoocclusive device for treatment of aneurysms

Abstract

The three-dimensional device is adapted to be inserted into a portion of a vasculature for occluding the portion of the vasculature for use in interventional therapy and vascular surgery. The device is formed from a multi-stranded micro-cable having a plurality of flexible strands of a shape memory material and at least one radiopaque strand. The flexible strands in a multi-stranded micro-cable of the device can be helically wound, or can be configured as parallel, longitudinal strands, and can also be formed to have a secondary, three-dimensional therapeutic configuration, such as helical, conical, spherical, or other geometric shapes. The strands can be made of a shape memory nickel titanium alloy, that is highly flexible at a temperature appropriate for introduction into the body via a catheter, and that after placement will take on the therapeutic shape. The device can also include a therapeutic agent, and can be bundled by an outer cover to constrain the strands of the micro-cable about a longitudinal axis to produce a composite banded cable. The radiopaque strand can have a core strand with a plurality of intermittently spaced apart enlarged radiopaque portions that may be a plurality of beads of radiopaque material spaced apart and mounted on the core strand, or a plurality of coils intermittently wound about and spaced apart on the core strand. A polyhedral occlusive device is also provided, adapted to be inserted into a portion of a vasculature for occluding a portion of the vasculature, for use in interventional therapy and vascular surgery. One or more therapeutic fibers can also be woven into the coil to enhance treatment of the side after placement of the device.

Description

RELATED APPLICATIONS [0001] This is a continuation-in-part of Ser. No. 09 / 019,841 filed Feb. 6, 1998, which was a continuation-in-part of Ser. No. 08 / 986,004 filed Dec. 5, 1997.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention relates generally to implantable devices for interventional therapeutic treatment or vascular surgery, and concerns a stranded micro-cable with enhanced radiopacity that can be used to fabricate a vascular device, a stent, a guidewire or the like. More particularly, the invention relates to three dimensional microcoil vasoocclusive devices fabricated from stranded micro-cable. [0004] 2. Description of Related Art [0005] The art and science of interventional therapy and surgery has continually progressed towards treatment of internal defects and diseases by use of ever smaller incisions or access through the vasculature or body openings, in order to reduce the trauma to tissue surrounding the treatment site. One important aspect...

AI Technical Summary

Benefits of technology

The present invention provides a micro-cable that can be used in interventional medicine to treat damage to the vasculature in the brain and other vessels. The micro-cable includes multiple strands of a flexible material, such as a shape memory alloy or super elastic alloy of nickel-titanium, with at least one strand being radiopaque. The use of multiple strands allows for the placement of vasoocclusive devices in a more complex shape as they are forced through a catheter. The construction also eliminates the necessity of a safety wire and prevents stretching of the cable in the event of failure of a single strand. The invention solves the problem of kinking and provides a continuous indication under fluoroscopy of the deployed configuration of the device.

Problems solved by technology

However, the range of diameters of wire and the configurations of the resulting geometry ofboth the coils and the devices developed which can be used have been limited by both the relatively small diameter of wire that must be used to avoid trauma and allow housing within the catheter prior to deployment, and the requirement for larger diameters to provide for radiopaque markers and mechanical robustness.

In many cases this has resulted in primary wire characteristics in the coil that are unacceptably stiff, very delicate, or subject to kinking.

More specifically, it has been found that single strands of small diameter nickel-titanium alloys, as well as other metal alloys, used to form vasoocclusive devices can be kinked if twisted and pulled as can occur during or after deployment from a catheter, especially if the doctor wishes to withdraw a partially deployed coil because it is somehow incorrect in size, shape or length to repair the damage to the vessel.

Also, single wire coils are more likely to cause trauma to the area to be treated if the wire is of a sufficient diameter to provide adequate tensile strength.

Furthermore, such small diameter wires of some of these materials such as nickel-titanium, stainless steel and the like, are not generally radiopaque with currently available equipment, necessitating the use of radiopaque markers attached to the device, with the resultant possible diminution of functionality and increased diameter.

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