Structures for permanent occlusion of a hollow anatomical structure

1. An apparatus for treating a hollow anatomical structure, said apparatus comprising:

an implant sized for insertion into said hollow anatomical structure, said implant being elongate wherein said implant has an axial dimension which is many times greater than its radial dimension, said implant having a distal section and a proximal section;

said implant comprising a plurality of loose, non-knit and non-woven fibers, each fiber having a number of bends along the length thereof, each bend having an angle such that when each fiber is compressed radially, the bend angle generally decreases and the fiber has a greater axial length and a smaller radial width than when uncompressed, each of said fibers being formed from one or more bioabsorbable materials and having a denier of about 0.1 to about 10;

said implant being radially compressible to facilitate insertion into said hollow anatomical structure, and said implant being expandable toward a radially larger, less radially dense elongate configuration, the expansion facilitated by a tendency of the bends in the individual fibers to return to their decreased angles, increasing their radial width of the fibers and decreasing their length, when an amount of radial compression is decreased, said implant being further configured to conform to the lumen of the hollow anatomical structure following insertion therein and to radially fill said hollow anatomical structure; and

a tether secured to said distal section of said implant and extending along the entire length of said implant and substantially parallel thereto;

said plurality of fibers being formed into an elongate bundle of fibers comprising at least about 500 fibers, said bundle being folded back along its longitudinal axis to form said implant, said implant having a folded end adjacent the distal section of the implant and a pair of elongate branches extending from said folded end of said implant, the elongate branches lying closely adjacent one another and extending parallel to one another along the length of said implant;

said fibers of said elongate branches remaining loose wherein they are free to move and are not generally confined or restrained relative to each other.

2. The apparatus of claim 1 , wherein said fibers are randomly arranged.

3. The apparatus of claim 1 , wherein said fibers are formed from an alpha-hydroxy acid.

4. The apparatus of claim 1 , wherein said fibers are formed from material selected from the group consisting of polyglycolic acid, polyglycolic-co-lactic acid, polylactic-glycolic acid, polyglycolide-co-lactide, and polyglycolide.

5. The apparatus of claim 1 , wherein said implant comprises between 500 and 500,000 fibers.

6. The apparatus of claim 1 , wherein said tether is configured to limit migration of said implant when in said hollow anatomical structure.

7. The apparatus of claim 1 , wherein said tether is configured to extend beyond the proximal section of said implant.

8. The apparatus of claim 1 , wherein said tether extends within said implant.

9. The apparatus of claim 1 , wherein said tether is formed from a bioabsorbable material having a first bioabsorption rate, said fibers are formed from a bioabsorbable material having a second bioabsorption rate, and said first bioabsorption rate differs from said second bioabsorption rate.

10. The apparatus of claim 9 , wherein said first bioabsorption rate is lower than said second bioabsorption rate.

11. The apparatus of claim 9 , wherein said first bioabsorption rate is higher than said second bioabsorption rate.

12. The apparatus of claim 1 , wherein said fibers have a bioabsorption time of 2-24 weeks after implantation.

13. The apparatus of claim 1 , wherein said implant additionally comprises a drug.

14. The apparatus of claim 1 . wherein said implant additionally comprises a sclerosant.

15. The apparatus of claim 1 , wherein said fibers comprise first fibers having a first bioabsorption rate and second fibers having a second bioabsorption rate, and wherein said first bioabsorption rate differs from said second bioabsorption rate.

16. The apparatus of claim 1 , wherein the number of bends along the length of the fibers are spaced apart along said fiber by one or more distances which are significantly smaller than the length of said fiber.

17. The apparatus of claim 1 , wherein an outer surface of said implant is abrasive.