Implant including a coil and a stretch-resistant member
This invention is directed to implantable coils and, more particularly, to a coil implant having a stretch-resistant member internal to the coil. The implant of the invention is able to freely articulate and torque prior to delivery. Once delivered, the implant is no longer stretch resistant and is therefore able to substantially conform to the vascular site.
1. An implant, comprising:
a primary coil defining a lumen disposed along an axis, the primary coil having a proximal end defining a proximal aperture and a distal end defining a distal aperture;
a secondary coil further defining the proximal aperture which secondary coil is coaxial with the primary coil and having an outer diameter, an inner diameter, a distal end and a proximal end;
a stretch-resistant member disposed within the lumen;
a member comprising a proximal member section, a distal member section and a central axis that intersects the proximal aperture, the distal member section being coupled to the stretch-resistant member within the lumen, the proximal member section having an engagement portion exterior to the lumen wherein said engagement portion and said member are capable of moving distally into the lumen, the distal member section configured to engage the inner diameter of the secondary coil to prevent proximal extraction of the member from the secondary coil, the member being freely distally movable with respect to said secondary coil; and
a retainer engaging the distal aperture and coupled to the stretch-resistant member within the lumen.
2. The implant of claim 1 , wherein the engagement portion and member are capable of moving distally completely into the lumen.
3. The implant of claim 1 , wherein the member freely is movable with respect to said primary coil.
4. The implant of claim 1 , wherein the primary coil has an outer and an inner diameter and the secondary coil has an outer diameter which is smaller than or equal to the inner diameter of the primary coil.
5. The implant of claim 1 , wherein the proximal end of the primary coil is adjacent to or partially envelopes the distal end of the secondary coil.
6. The implant of claim 1 , wherein the primary coil and the secondary coil are independently comprised of a metal wire.
7. The implant of claim 6 , wherein the primary coil wire is comprised of a metal selected from the group consisting of platinum, palladium, rhodium, rhenium, iridium, gold, silver, tungsten, tantalum, an alloy of two or more of these metals, or a super elastic metal.
8. The implant of claim 7 , wherein the primary coil wire is a platinum alloy.
9. The implant of claim 1 , wherein the primary coil and the secondary coil are comprised of a primary helix which is itself wound and set into a secondary shape.
10. The implant of claim 9 , wherein the secondary shape is selected from helical, spheroidal, cubic, and tertiary space-filling shapes.
11. The implant of claim 1 , wherein the stretch-resistant member is comprised of a polymer.
12. The implant of claim 11 , wherein the polymer is biodegradable or non-biodegradable.
13. The implant of claim 12 , wherein the polymer is polypropylene.
14. The implant of claim 11 , wherein the stretch-resistant member is further comprised of a bioactive coating.
15. The implant of claim 14 , wherein the bioactive coating is selected from the group consisting of a growth factor, a gene, an oligonucleotide, a peptide, a marine biopolymer, a monosaccharide, a disaccharide, a polysaccharide, collagen and combinations thereof.
16. The implant of claim 1 , further comprising a plurality of fibers.
17. The implant of claim 16 , wherein the fibers are wrapped around the primary and/or secondary coil at least one time.
18. The implant of claim 16 , wherein each fiber is wrapped around the stretch resistant member at least one time.
19. The implant of claim 17 or claim 18 , wherein each fiber is wrapped around at least two times.
20. The implant of claim 16 , wherein the fibers are comprised of a copolymer of glycolic acid and lactic acid.
21. The implant of claim 20 , wherein the fibers further comprise a bioactive coating.
22. The implant of claim 21 , wherein the coating is either a lubricious hydrophilic coating or a hydrophobic coating.
23. The implant of claim 21 , wherein the coating comprises a copolymer of lactic acid and glycolic acid.
24. The implant of claim 16 , wherein the fibers are comprised of a biodegradable polymer.
25. The implant of claim 24 , wherein the biodegradable polymer is selected from the group consisting of polyglycolic acid, polycaprolactone, polyhydroxybutyrate valearte, polyorthoester, polylactic acid, poly(p-dioxanone), poly(valerolactone), poly(tartronic acid), poly(β-malonic acid), poly(propylene fumarate), poly(anhydrides), and tyrosine-based polycarbonates.
26. The implant of claim 25 , wherein the polymer is polyglycolic acid and polylactic acid and is present in a ratio of polyglycolic acid to polylactic acid selected from 99:1; 95:5, 90:10, 50:50, 10:90, 5:95, or 1:99.
27. The implant of claim 1 , wherein the retainer has a portion that is exterior to the lumen of the primary coil.
28. The implant of claim 27 , wherein the portion that is exterior has a shape that is rounded.
29. The implant of claim 1 , wherein the retainer is comprised of a polymer.
30. The implant of claim 29 , wherein the polymer is polypropylene.
31. The implant of claim 1 , wherein the distal portion of the member having a central axis that intersects the proximal aperture comprises an eyelet.
32. The implant of claim 31 , wherein the stretch resistant member is coupled to the eyelet with a knot.
33. The implant of claim 32 , where in the knot is a half-hitch or a hitch knot.
34. The implant of claim 1 , wherein the engagement portion is disengageable from a positioner by chemical detachment, electrolytic detachment, mechanical detachment, hydraulic detachment, or thermal detachment.
35. A method of embolizing a vascular site in a patient, comprising:
introducing to said site via a positioner an implant, the implant comprising
a primary coil defining a lumen disposed along an axis, the primary coil having a proximal end defining a proximal aperture and a distal end defining a distal aperture;
a secondary coil further defining the proximal aperture which secondary coil is coaxial with the primary coil and having an outer diameter, an inner diameter, a distal end and a proximal end;
a stretch-resistant member disposed in the lumen;
a retainer engaging the distal aperture and coupled to the stretch-resistant member within the lumen; and
a member comprising a proximal member section, a distal member section and a central axis that intersects the proximal aperture, the distal member section being coupled to the stretch-resistant member within the lumen, the proximal member section having an engagement portion exterior to the lumen, wherein said member is capable of moving distally into the lumen, the distal member section configured to engage the inner diameter of the secondary coil to prevent proximal extraction of the member from the secondary coil, the member being freely distally movable with respect to said secondary coil;
detaching said implant from the positioner by disengaging the positioner from the engagement portion of said member, wherein said detaching step comprises moving the member distally into the lumen; and
embolizing the vascular site.
36. The method of claim 35 , wherein the implant substantially conforms to the vascular site.
37. The method of claim 35 , wherein the positioner is a microcatheter.
38. The method of claim 35 , wherein said detaching said implant from the positioner comprises chemical detachment, electrolytic detachment, mechanical detachment, hydraulic detachment, or thermal detachment.
39. The method of claim 38 , wherein said detaching the implant comprises mechanical detachment, the mechanical detachment comprising moving a cord to disengage the implant.
40. The method of claim 38 , wherein after detachment, the member and engagement portion are free to move within the lumen.
41. The method of claim 40 , wherein after detachment the engagement portion and member are contained in the lumen.
42. The method of claim 41 wherein the engagement portion is completely contained in the lumen.
43. The method of claim 38 , wherein the implant is stretch-resistant prior to detachment from the positioner.
44. The method of claim 43 , wherein the implant is no longer stretch-resistant after detachment from the positioner.
45. The method of claim 38 , further comprising delivering additional implants.