Method and apparatus for gastrointestinal tract ablation for treatment of obesity
Devices and methods for ablating tissue in the wall of various organs of the gastrointestinal tract of a patient in order to cure or ameliorate metabolic pathophysiological conditions such as obesity, insulin resistance, or type 2 diabetes mellitus are provided. Ablational treatment of target areas may be fractional or partial, rendering a post-treatment portion of target tissue ablated and another portion that is substantially intact. Fractional ablation is achieved by controlling the delivery of ablational energy across the surface area being treated, and controlling the depth of energy penetration into tissue. Surface area control of energy delivery may controlled by the spatial pattern of distributed ablation elements or by the selective activation of a subset of a dense pattern of ablation elements. Embodiments of the device include an ablational electrode array that spans 360 degrees and an array that spans an arc of less than 360 degrees.
1. A method of ablationally treating tissue at a target area in a gastrointestinal tract of a patient with a pathophysiological metabolic condition comprising:
determining an ablation depth to treat the pathophysiological metabolic condition;
selecting an ablation structure comprising a fixed inter-electrode spacing configured to ablate the target area to a predetermined depth, wherein the predetermined depth corresponds to the ablation depth determined to treat the pathophysiological condition;
advancing the ablation structure adjacent to the target area, wherein the target area is a portion of the gastrointestinal tract that includes at least a portion of the duodenum;
moving the ablation structure into contact with a surface of the tissue within the target area, wherein the ablation structure comprises a plurality of electrodes arranged in a pattern having the fixed inter-electrode spacing;
delivering radio frequency energy from the ablation structure to the surface of the tissue within the target area; and
forming a volume of ablated tissue from the energy delivered to the surface of the tissue within the target area by controlling a delivery of energy across the surface of the tissue within the target area such that the surface of the tissue within the target area comprises a portion of the tissue that is included in the volume of ablated tissue and a portion of the tissue that is not included in the volume of ablated tissue, wherein the volume of ablated tissue has the predetermined depth extending from the surface of the tissue, and wherein the predetermined depth extending from the surface of the tissue is controlled by the fixed inter-electrode spacing.
2. The method of claim 1 , wherein controlling the delivery of energy across the surface of the tissue within the target area comprises:
moving the ablation structure a distance after the first energy delivery; and
delivering sufficient energy from the ablation structure to the tissue within the target area to achieve ablation a second time.
3. The method of claim 1 , wherein controlling the predetermined depth extending from the surface of the tissue includes controlling the delivery of energy inwardly from the surface of the tissue such that sufficient energy to achieve ablation is delivered to some layers and insufficient energy is delivered to other layers to achieve ablation.
4. The method of claim 1 , wherein delivering radio frequency energy from the ablation structure comprises activating all of the plurality of electrodes.
5. The method of claim 1 , wherein delivering radio frequency energy from the ablation structure comprises selectively activating a subset of the plurality of electrodes.
6. The method of claim 1 , wherein the ablation structure is configured to be expandable.
7. The method of claim 6 , wherein the ablation structure comprises an expandable balloon.
8. The method of claim 7 , wherein the expandable balloon is non distensible.
9. The method of claim 1 , wherein the pathophysiological metabolic condition includes any one or more of type 2 diabetes, insulin resistance, obesity, or metabolic syndrome.
10. The method of claim 1 , wherein the tissue within the target area comprises cells with a functional capacity, and wherein the functional capacity of the cells after the tissue is treated is reduced such that the cells are no longer functional.
11. The method of claim 1 , wherein the tissue within the target area comprises cells with a functional capacity, and wherein the functional capacity of the cells after the tissue is treated is reduced such that the cells remain partially functional.
12. The method of claim 1 , wherein the tissue within the target area comprises cells with a functional capacity, and wherein the functional capacity relates to cell secretion of contents or hormones.
13. The method of claim 1 , wherein controlling the delivery of energy across the surface of the tissue within the target area and controlling the predetermined depth extending from the surface of the tissue within the target area comprises controlling one or more ablation energy parameters.
14. The method of claim 13 , wherein the one or more ablation energy parameters comprise an amount of energy, an energy density, or a duration of time.
15. The method of claim 14 , wherein controlling a duration of time comprises continuously delivering energy for a predetermined amount of time.
16. The method of claim 14 , wherein controlling a duration of time comprises repeatedly delivering discrete pulses of energy.
17. The method of claim 1 , wherein controlling the predetermined depth extending from the surface of the tissue consists of ablating some portion of tissue within the epithelial layer.
18. The method of claim 1 , wherein controlling the predetermined depth extending from the surface of the tissue consists of ablating some portion of tissue within the epithelial layer and the lamina propria.
19. The method of claim 1 , wherein controlling the predetermined depth extending from the surface of the tissue consists of ablating some portion of tissue within the epithelial layer, the lamina propria, and the muscularis mucosae.
20. The method of claim 1 , wherein controlling the predetermined depth extending from the surface of the tissue consists of ablating some portion of tissue within the epithelial layer, the lamina propria, the muscularis mucosae, and the submucosa.
21. The method of claim 1 , wherein controlling the predetermined depth extending from the surface of the tissue consists of ablating some portion of tissue within the epithelial layer, the lamina propria, the muscularis mucosae, the submucosa, and the muscularis propria.
22. The method of claim 1 , further comprising deriving energy for transmitting from an energy source that is controlled by a control system.
23. The method of claim 22 , further comprising feedback controlling the energy transmission so as to provide any of a specific power, power density, energy, energy density, circuit impedance, or tissue temperature.
24. The method of claim 1 , wherein the ablation structure is positioned on a distal end of an elongate shaft.
25. The method of claim 1 , wherein the ablation structure is adapted to fit within a working channel of an endoscope.