Methods and apparatus for anchoring within the gastrointestinal tract
The present invention relates to an anchor configured for minimally-invasive implantation and sized to remain securely positioned within at least a portion of the gastrointestinal tract of an animal. The anchor includes a radial spring formed from an elongated resilient member shaped into an annular wave pattern about a central axis. The anchor defines a central lumen and provides an outward radial force, while allowing for substantial flexure about its perimeter. The anchor is generally removable, but can include fasteners, such as barbs, to further secure it to the surrounding anatomy. In some embodiments, the anchor includes a connector coupling a fixed portion to a removable portion. Further, the anchor can be used to secure a medical device within the body, such as a flexible sleeve within the intestine.
1. A gastrointestinal implant device comprising:
a flexible sleeve configured to carry chyme from a proximal end of the sleeve to a distal end of the sleeve and adapted to extend into the intestine, the distal end of the sleeve being unsupported; and
a wave anchor coupled to a proximal portion of the sleeve, the wave anchor formed of an elongated resilient member and being adapted for attachment within an animal body, the wave anchor defining a central lumen diameter that is variable between a relaxed state and a compressed state, the wave anchor comprising ends separated by an axial length, wherein the axial length is within a range of about 1 inch to about 2 inches;
a terminal proximal end of the flexible sleeve being matched in shape to a shape of a terminal proximal end of the wave anchor at a terminal proximal end of the implant device.
2. The device of claim 1 , wherein the axial length is within a range of about 1.25 inches to about 1.5 inches.
3. The device of claim 1 , wherein a ratio of the axial length to the central lumen diameter in a relaxed state is at least about 0.8.
4. The device of claim 1 wherein the wave anchor accommodates a diameter of an adult human's intestine of about 45 millimeters.
5. The device of claim 1 wherein the wave anchor has a single wave in a single revolution.
6. The device of claim 5 wherein the single wave is formed about a central axis, the elongated resilient member defining an oscillating pattern about the central axis alternating between the first and second ends.
7. The device of claim 6 wherein the oscillating pattern has at least four oscillations.
8. The device of claim 6 wherein the elongated resilient member comprises a material selected from the group consisting of: metals, alloys, plastics, and combinations thereof.
9. The device of claim 6 wherein the elongated resilient member comprises a shape memory alloy.
10. The device of claim 9 , wherein the shape memory alloy is a Nickel Titanium alloy.
11. The device of claim 6 wherein the elongated resilient member includes a plurality of strands.
12. The device of claim 11 wherein some of the plurality of strands have different physical properties.
13. The device of claim 6 wherein the elongated resilient member comprises a first length having an associated physical property and a second length having a different associated physical property.
14. The device of claim 13 wherein the physical property is resiliency.
15. The device of claim 13 wherein the physical property is thickness.
16. The device of claim 13 wherein the physical property is cross sectional profile.
17. The device of claim 1 wherein a ratio of the axial length to the central lumen diameter when implanted is at least about one.
18. The device of claim 1 wherein a relaxed diameter of the wave anchor is about 45 millimeters.
19. The device of claim 1 , comprising protrusions extending from the wave anchor.
20. The device of claim 19 wherein the protrusions include a plurality of barbs, and wherein each of the plurality of barbs comprises an elongated member, attached at one end to the wave anchor, the other end extending generally outward from a central axis of the wave anchor, the barb sized to engage muscular tissue of the surrounding intestine.