Tissue extraction devices and methods
Tissue may be cut and extracted from an interior location in a patient's body using a probe or tool which both effects cutting and causes vaporization of a liquid or other fluid to propel the cut tissue through an extraction lumen of the cutting device. The cutting may be achieved using an electrosurgical electrode assembly, including a first electrode on a cutting member and a second electrode within a cutting probe or tool.
1. A system for resecting tissue, comprising:
a tissue resecting probe including:
an outer sleeve having a side window configured to receive tissue therein, the outer sleeve comprising a first polarity electrode; and
an inner sleeve disposed within the outer sleeve, the inner sleeve comprising a second polarity electrode;
wherein the inner sleeve is movable relative to the outer sleeve between a window-open position and a window-closed position; and
a controller including an RF generator operatively connected to the tissue resecting probe;
wherein in a first RF mode, the controller is configured to supply RF current between the first polarity electrode and the second polarity electrode to resect tissue extending into the side window while the inner sleeve is moving from the window-open position to the window-closed position;
wherein in a second RF mode, the controller is configured to supply RF current between the first polarity electrode and the second polarity electrode to coagulate tissue.
2. The system of claim 1 , wherein the controller is configured to selectively move or terminate movement of the inner sleeve relative to the outer sleeve.
3. The system of claim 1 wherein the controller is configured to supply RF current between the first polarity electrode and the second polarity electrode to coagulate tissue when the inner sleeve is not moving relative to the outer sleeve.
4. The system of claim 1 , wherein the second polarity electrode includes a leading edge and a trailing edge.
5. The system of claim 4 , wherein the leading edge and the trailing edge have different electrical characteristics.
6. The system of claim 4 , wherein the leading edge and the trailing edge are formed from dissimilar materials.
7. The system of claim 6 , wherein the leading edge comprises a highly conductive material configured to form plasma about the leading edge when subjected to RF current.
8. The system of claim 6 , wherein the trailing edge comprises a resistive material configured to resistively heat the trailing edge when subjected to RF current.
9. The system of claim 8 , wherein the trailing edge includes a capacitive coating.
10. The system of claim 8 , wherein the trailing edge includes a dielectric coating.
11. The system of claim 4 , wherein the leading edge is configured to resect tissue and the trailing edge is configured to coagulate tissue.
12. The system of claim 4 , wherein the leading edge is scalloped.
13. The system of claim 12 , wherein a plasma is formed along the leading edge when subjected to RF current, and projecting edges of the leading edge are configured to form plasma having a higher energy density than the plasma formed along recessed portions of the leading edge.
14. The system of claim 1 , further comprising a fluid management system configured to circulate a fluid through a space in a patient's body with a first flow into the space and a second flow out of the space to thereby occupy or distend the space.
15. The system of claim 14 , wherein the fluid management system is configured to extract the fluid and resected tissue from the space through an extraction lumen of the inner sleeve.
16. The system of claim 15 , wherein the fluid management system includes a saline source.
17. The system of claim 16 , wherein the fluid management system is configured to recirculate the fluid from the space back to the saline source.