Radially expandable gastrointestinal stimulation device

1. A gastrointestinal stimulation device comprising:

a fixation device able to withstand a gastric environment, the fixation device comprising a radially expandable member having an outer portion; and

at least one electrode coupled to the outer portion of the fixation device so that the electrode is radially outwardly oriented,

wherein the radially expandable member is configured to radially expand to fix the fixation device within a portion of a gastrointestinal tract in the duodenum or adjacent the pyloric sphincter to permit passage of solid material therethrough and so that the at least one electrode is in electrical contact with the gastrointestinal tract.

2. The gastric stimulation device of claim 1 wherein the radially expandable member comprises a self-expanding member having a first compressed position and a second radially expanded position.

3. The gastric stimulation device of claim 1 wherein the fixation device comprises an electrode housing defining the outer portion of the fixation device, wherein the at least one electrode is located on the electrode housing so that at least a portion of the at least one electrode is exposed.

4. The gastric stimulation device of claim 3 wherein the electrode housing comprises a connector configured to couple the electrodes to an electronic circuit configured to provide electrical stimulation to the gastrointestinal tract through the electrodes.

5. The gastric stimulation device of claim 3 further comprising:

an attachment device coupled to the housing and configured to attach the housing to the stomach wall.

6. The gastric stimulation device of claim 3 wherein the electrode housing further comprises an electronic circuit configured to provide electrical stimulation to the gastrointestinal tract through the at least one electrode.

7. The gastric stimulation device of claim 6 further comprising a coupler configured to removably couple a power source to the electronic circuit.

8. The gastric stimulation device of claim 7 wherein the coupler comprises a docking mechanism configured to removably couple the power source adjacent the electrode housing.

9. The gastric stimulation device of claim 8 wherein the docking mechanism comprises a magnetic coupling mechanism.

10. The gastric stimulation device of claim 1 further comprising an electronics housing including electronic circuitry, wherein the electronics housing comprises an electrical connector coupling the electronic circuitry to the at least one electrode, wherein the electronic circuitry is configured to deliver electrical stimulation through the at least one electrode.

11. The gastric stimulation device of claim 10 further comprising a coupling mechanism for removably coupling the electrical connector of the electronics housing to the at least one electrode of the electrode housing.

12. The gastric stimulation device of claim 11 wherein the electronics housing further comprises a power source for providing power to the electronic circuitry.

13. A method of implanting a stimulator in a gastrointestinal tract comprising the steps of:

providing a fixation device comprising a radially expandable member; an outer portion; and at least one electrode coupled to the outer portion of the fixation device;

advancing the fixation device using an elongate member, to an attachment site within a gastrointestinal tract in the duodenum or adjacent the pyloric sphincter;

radially expanding the fixation device so that the at least one electrode is in electrical contact with tissue of the gastrointestinal tract.

14. The method of claim 13 wherein the step of radially expanding comprises releasing the fixation device from a constrained configuration to permit the fixation device to expand.

15. The method of claim 13 wherein the step of radially expanding comprises mechanically expanding the fixation device.

16. The method of claim 13 further comprising the steps of providing a stimulator configured to supply electrically stimulating signals to tissue of the gastrointestinal tract through the at least one electrode.

17. The method of claim 16 wherein the step of providing the stimulator comprises providing a stimulator with the fixation device.

18. The method of claim 17 wherein the step of providing the stimulator comprises implanting the stimulator subcutaneously and coupling the stimulator to the at least one electrode.

19. The method of claim 17 wherein the step of providing the stimulator comprises attaching the stimulator to a wall of a stomach of the gastrointestinal tract and coupling the stimulator to the at least one electrode.

20. The method of claim 13 further comprising the step of treating obesity by stimulating the gastrointestinal tract with the electrode so as to control a pylorus.

21. The method of claim 13 , further comprising treating obesity by stimulating the tissue of the gastrointestinal tract with the electrode, wherein the fixation device withstands long-term exposure to the gastrointestinal tract sufficiently to treat the obesity.