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 method of treatment comprising the steps of:
extending one end of an unsupported, flexible sleeve into the intestine of an animal body;
attaching a proximal end of the sleeve within the intestine of the animal body only distal to the pylorus and in the duodenal bulb using a wave anchor; and
channeling chyme from the stomach into the intestine through the sleeve.
2. The method of claim 1 wherein attaching includes attaching the wave anchor in the duodenum.
3. The method of claim 1 wherein the wave anchor has an axial length within a range of about 25 millimeters to about 50 millimeters.
4. The method of claim 1 wherein the wave anchor accommodates a diameter of an adult human's intestine of about 45 millimeters.
5. The method of claim 1 wherein the wave anchor has a single wave in a single revolution.
6. The method of claim 5 wherein the single wave includes an elongated resilient member formed about a central axis, the wave anchor having a first end and a second end and defining a central lumen therebetween, the elongated resilient member defining an oscillating pattern about the central axis alternating between the first and second ends.
7. The method of claim 6 wherein the oscillating pattern has at least four oscillations.
8. The method 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 method of claim 6 wherein the elongated resilient member comprises a shape-memory alloy.
10. The method of claim 9 , wherein the shape-memory alloy is a Nickel-Titanium alloy.
11. The method of claim 6 wherein the elongated resilient member includes a plurality of strands.
12. The method of claim 11 wherein some of the plurality of strands have different physical properties.
13. The method 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 method of claim 13 wherein the physical property is resiliency.
15. The method of claim 13 wherein the physical property is thickness.
16. The method of claim 13 wherein the physical property is cross-sectional profile.
17. The method of claim 1 wherein the wave anchor defines a central lumen diameter that is variable between a relaxed state and a compressed state, the ends being separated by an axial length, wherein the ratio of the implanted axial length to diameter is at least about one.
18. The method of claim 17 wherein the relaxed diameter is about 45 millimeters.
19. The method of claim 1 wherein attaching includes engaging the intestine with protrusions extending from the wave anchor, the wave anchor having a single wave in a single revolution.
20. The method 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 the central axis, the barb sized to engage muscular tissue of the surrounding intestine.