Medical ablation system and method of use
Cartilage and other tissues are treated by generating a plasma in an interior space of a probe and exposing the tissue to the plasma. The plasma is released through a gap in a working end of the probe.
1. A method for treating a target tissue, said method comprising:
providing a probe having an interior space comprising a gap in a working end with a working surface, wherein the gap has an interior periphery and an exterior periphery with a spacing therebetween;
igniting a conductive media in the gap to produce a plasma within the gap, wherein the plasma propagates outwardly from the working surface; and
exposing the target tissue to the plasma, wherein the gap is sufficiently fluid tight to inhibit liquid flow but permit plasma propagation therethrough.
2. A method as in claim 1 , wherein the plasma is ignited by applying electrical energy to the conductive media from opposite polarity electrodes.
3. A method as in claim 2 , wherein a first polarity electrode is disposed in proximity to the inner periphery.
4. A method as in claim 3 , wherein the first polarity electrode is in a fluid channel in communication with said inner periphery.
5. A method as in claim 4 , further comprising a second polarity electrode in the working end in potential fluid communication with said exterior periphery.
6. A method as in claim 1 , wherein a mean dimension between said interior and exterior peripheries of the gap is from 0.005 inch to 0.25 inch.
7. A method as in claim 1 , wherein the total area of the gap is from 0.01 mm 2 to 10 mm 2 .
8. A method as in claim 1 , wherein the gap has an annular configuration, a linear configuration, an oval configuration, an elongated configuration, or a star-shaped configuration.
9. A method as in claim 1 , wherein a propagation rate of the plasma is controlled by varying a pressure of the conductive media in the interior space.
10. A method as in claim 9 , wherein the conductive media is introduced into the interior space under a controlled pressure.
11. A method as in claim 9 , wherein the conductive media is removed from the interior space under a controlled negative pressure.
12. A method as in claim 1 , wherein igniting the conductive media comprises establishing a continuous loop flow of a conductive media through the interior space wherein a portion of the conductive media is ignited within the interior space and a remainder exits the interior space.
13. A method as in claim 1 , wherein a propagation rate of the plasma is controlled by varying an inlet pressure of conductive media in an inlet channel and an outlet pressure of conductive media in the gap.
14. A method as in claim 1 , wherein the plasma propagates from the working surface by a distance less than 2 mm.
15. A method as in claim 1 , wherein the plasma has a temperature less than 80° C.
16. A method as in claim 1 , wherein the tissue comprises cartilage.
17. A method as in claim 1 , wherein the conductive media comprises saline.
18. A method as in claim 1 , wherein the target tissue is submerged in the conductive media.
19. A method for treating a target tissue, said method comprising:
providing a probe having space comprising a gap in a working end with a working surface;
igniting a conductive media in the gap to produce a plasma within the gap, wherein the plasma propagates outwardly from the working surface;
exposing the target tissue to the plasma; and
controlling a rate of propagation through the gap, wherein the plasma propagation rate is controlled by controlling a dimension of said gap.
20. A method as in claim 19 , wherein the plasma propagation rate is controlled by controlling a width of said gap.
21. A method as in claim 20 , wherein the plasma propagation rate is controlled by controlling the dimension of said gap between a plasma ignition region and the working surface.