Ablation systems, devices and methods for the treatment of tissue

1. A device for ablating duodenal mucosal tissue of a patient comprising:

an elongate shaft having a proximal portion and a distal portion;

at least one expandable assembly positioned on the elongate shaft distal portion and comprising a dog-bone shaped balloon;

at least one fluid delivery lumen configured to enter an interior of the balloon;

a plurality of fluid delivery nozzles connected to receive fluid from the at least one fluid delivery lumen in the interior of the balloon, wherein said plurality of fluid delivery nozzles are mounted through a central portion of the dog-bone shaped balloon and configured to deliver the fluid to a region between distal and proximal enlarged ends of the dog-bone shaped balloon; and

wherein the device is constructed and arranged to ablate the duodenal mucosal tissue while avoiding damaging duodenal adventitial tissue.

2. The device according to claim 1 , wherein the device is constructed and arranged to avoid ablating at least the outermost 100 microns of the duodenal submucosal tissue.

3. The device according to claim 1 , wherein the device is constructed and arranged to minimize damage to at least one of the pylorus, the ampulla of Vater, or the duodenal muscularis layer.

4. The device according to claim 1 , wherein the device is constructed and arranged to ablate duodenal mucosal tissue in a curved segment of duodenum.

5. The device according to claim 1 , wherein the device is constructed and arranged to treat a first length of duodenum in a first ablative fluid application and a second length of duodenum in a second ablative fluid application.

6. The device according to claim 1 , wherein the plurality of fluid delivery nozzles are constructed and arranged to deliver a near 360° delivery of fluid.

7. The device according to claim 1 , wherein the fluid comprises an ablative fluid selected from the group consisting of steam, vaporized fluid at a temperature less than 100° C., and gas at a temperature between 60° C. and 99° C.

8. The device according to claim 1 , wherein the fluid comprises an ablative fluid comprises a chemical agent configured to ablate tissue.

9. The device according to claim 8 , wherein the chemical agent comprises a fluid selected from the group consisting of a sclerotic agent, an acid, a base, saline, an alcohol, carbon dioxide, nitrous oxide, nitrogen, acetic acid, and glycerol.

10. The device according to claim 1 , wherein the fluid comprises an ablative fluid comprising a visualizable material.

11. The device according to claim 10 , wherein the visualizable material comprises material selected from the group consisting of: radiopaque agent; ultrasonically visible material; magnetically visible material; and combinations thereof.

12. The device according to claim 1 , further comprising a lumen sealing assembly constructed and arranged to seal a portion of a gastrointestinal tract.

13. The device according to claim 1 , wherein the device is constructed and arranged to limit forces applied to the duodenal wall to a level at or below 1 psi.

14. The device according to claim 1 , wherein the device is constructed and arranged to ablate a tissue layer of at least 500 microns in thickness.

15. The device according to claim 1 , wherein the plurality of fluid delivery nozzles comprise gas jet nozzles.

16. The device according to claim 1 , wherein the plurality of fluid delivery nozzles comprise rotatable nozzles.

17. The device according to claim 16 , further comprising a controller configured to adjust the direction of the rotatable nozzles.

18. The device according to claim 1 , wherein the plurality of fluid delivery nozzles comprises a nozzle configured to deliver a cone-shaped spray of the ablative fluid.

19. The device according to claim 1 , wherein the balloon comprises a non-compliant balloon.

20. The device according to claim 1 , wherein the balloon comprises a hydrophilic coating on its external surface.