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Adding microscopic porosity to the surface of a microcoil to be used for medical implantation

Adding microscopic porosity to the surface of a microcoil to be used for medical implantation description/claims

This application is a Continuation of application Ser. No. 11/340,422, filed 26 Jan. 2006 which was based on Provisional Application No. 60/647,516, filed 26 Jan. 2005.

Microcoils have been developed for implantability into aneurysms as a means of promoting healing through the obstruction of pulsatile blood flow into the center of the promoting aneurysm. Such devices have become very successful in treatment of cranial aneurysms and as a method of treating and preventing stroke when such malformations are discovered.

Another embolic coil is known which includes a distal roughened, textured surface with pockets having diameters of about 0.125 to 50 microns and depths of about 0.25 to 20 microns to provide improved platelet adhesion and to promote clotting. Another type of removable occlusion system for treating the neck of an aneurysm includes a mesh portion with pores allowing blood to flow through the mesh portion. While such embolic devices have voids or pores that can promote clotting or allow blood flow through the device, it would be desirable to provide an embolic device that can further promote healing of a patient's vasculature.

One vasoocclusive coil is known that has an enhanced therapeutic strand structure that may be formed from or incorporate therapeutic or bioactive materials such as polyglycolic acid (PGA) or poly(D,L-lactic acid-co-glycolic acid) (PGLA), or other therapeutic materials. Another embolic device is known which includes embolizing elements made of a hydrophilic, macroporous, polymeric, hydrogel foam material.

While the microcoil treatment of aneurysms is highly effective in improving the prognosis for recovery of those with such malformations, it is believed that success rate of the procedures would be enhanced if new and effective methods of treatment of the micro coils could be used to enhance the healing process once the microcoils are placed. The present invention resolves these and other limitations in prior art devices.

The present invention treats microcoils and other implantable devices, using one or more of a variety of etching methods, which can include plasma etching, photolithography and chemical etching, to create microscopic voids in the surface of a microcoil which are complex in shape and adapted to receive into the surface by pressure, melting or deposition one or more of a variety of therapeutic agents, therapeutic materials and therapeutic plastic agents which can act to accelerate the healing process once the coil is in place. At the present time, agents which are believed to be appropriate for deposition in the voids created by the process include therapeutic drugs and agents such as PGA or PGLA, among others, which can act as an accelerant for the healing process.

The present invention accordingly provides for a vasoocclusive microcoil for therapeutic treatment of a patient's vasculature, including a vasoocclusive microcoil having at least a portion having a surface defining a plurality of voids or pores therein, and a therapeutic or bioactive material disposed within the plurality of voids or pores. The present invention also provides for a method for occluding a patient's vasculature, involving the steps of providing a vasoocclusive microcoil having at least a portion having a surface defining a plurality of voids therein, and a therapeutic/bioactive material disposed within the plurality of voids, and introducing the vasoocclusive microcoil into the patient's vasculature, whereby the therapeutic/bioactive material can act to accelerate a healing process in the patient's vasculature. The present invention also provides for a method for delivering a therapeutic agent or material to a patient's vasculature by such a microcoil having at least a portion with a surface having a plurality of voids or pores, and for controlling the delivery of the therapeutic agent or material by controlling the porosity of the surface of the microcoil. The present invention also provides for a method of delivering a hydrogel to a patient's vasculature by a microcoil having at least a portion with a surface having a plurality of voids or pores carrying the hydrogel. The present invention also provides for a method for forming porosity in a surface of a microcoil using one or more of a variety of etching methods, which can include plasma etching and sputtering.

The therapeutic agent or material may be a therapeutic drug or a therapeutic plastic agent which can act to accelerate the healing process once the coil is in place, and in a presently preferred aspect, the therapeutic agent or material may be polyglycolic acid or poly(D,L-lactic acid-co-glycolic acid), and/or a therapeutic drug. More broadly, the therapeutic material may be silk, collagen, elastin, polyglycolic acid, polylactic acid, poly(D,L-lactic acid-co-glycolic acid), poly(L-lactide), poly(L-lactide-co-D,L-lactide), poly(L-lactide-co-glycolide), poly(glycolide-co-trimethylene carbonate), polyethylene oxide, polydioxanone, polycaprolactone, hylauric acid, polyhydroxylbutyrate, poly(phosphazene), poly(D,L-lactide-co-caprolactone), poly(glycolide-co-caprolactone), polyvinyl alcohol, polyanhydrides thereof, poly(ortho esters) thereof, poly(phosphate esters) thereof, poly(amino acids) thereof, poly(hydroxy butyrates) thereof, copolymers thereof, composites thereof, or combinations thereof. The therapeutic material may also be ethylene-octene copolymer, polypropylene, polyethylene, polyacrylate, polyacrylamide, poly(hydroxyethyl methacrylate), polyurethane, polysiloxane, copolymers thereof, composites thereof, or combinations thereof.

Other features and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments in conjunction with the accompanying drawings, which illustrate, by way of example, the invention.

FIG. 1 is a perspective of a portion of a microcoil according to the invention.

FIG. 2 is a cross-section at 2-2 of FIG. 1.

FIG. 3 shows a portion of a helical multi-stranded microcoil formed according to the invention.

FIG. 4 shows a portion of a helical single-stranded microcoil formed according to the invention.

• Provisional Patent
• Utility Patent

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