Methods and apparatus for treating body tissue sphincters and the like
A plurality of structures that resiliently attract one another are provided for implanting in a patient around a body tissue structure of the patient. For example, the body tissue structure may be the esophagus, and the plurality of structures may be implanted in an annulus around the outside of the esophagus, the annulus being substantially coaxial with the esophagus. The attraction may be between annularly adjacent ones of the structures in the annulus, and it may be provided, for example, by magnets or springs. The array of structures is preferably self-limiting with respect to the smallest area that it can encompass, and this smallest area is preferably large enough to prevent the apparatus from applying excessive pressure to tissue passing through that area.
1. Apparatus for encompassing a patient's body tissue structure and for resiliently applying pressure to the encompassed tissue comprising:
a plurality of bodies that can be disposed in an annular array around the tissue structure so that each of the bodies contacts the tissue;
means associated with the bodies for resiliently attracting annularly adjacent ones of the bodies in the array to one another;
means associated with the bodies for keeping an area encompassed by the bodies always open; and
a plurality of links, each of which links extends only between a respective pair of the bodies that are adjacent to one another in the array, and each of which links is unconnected to any annularly adjacent link except by the body between that link and the annularly adjacent link, the link that extends between the bodies in each pair allowing the bodies in that pair to move apart in a direction that is annular of the array, and the link that extends between the bodies in each pair having at least one stop inside one of the bodies in that pair for stopping such movement apart of the bodies in that pair when those bodies have moved apart to an upper limit of such movement, the stop of each link that is inside one of the bodies being movable relative to that body.
2. The apparatus defined in claim 1 wherein the means for attracting comprises a magnet.
3. The apparatus defined in claim 1 wherein the means for attracting comprises a spring.
4. The apparatus defined in claim 1 wherein the means for keeping comprises contact between adjacent ones of the bodies.
5. The apparatus defined in claim 1 wherein each of the links is extendable from at least one of the bodies between which that link extends, and wherein the stop of each link is (1) inside the body from which that link is extendable, (2) movable relative to that body to permit extension of the link from the body, but (3) prevented by that body from leaving the inside of the body.
6. The apparatus defined in claim 5 wherein each of the links is extendable from both of the bodies between which that link extends.
7. The apparatus defined in claim 1 further comprising:
means for maintaining substantially equal spacing between adjacent ones of the bodies, while allowing that spacing to change.
8. The apparatus defined in claim 1 wherein the means for limiting comprises an arc shape of a surface of at least one of the bodies that faces the tissue structure.
9. The apparatus defined in claim 1 wherein the apparatus is adapted for implanting in the patient's body.
10. The apparatus defined in claim 1 wherein the apparatus has an initial substantially linear form that can be converted to a closed loop by connecting ends of the linear form.