Tissue extraction devices and methods
The tissue cutting device comprises an elongated assembly including both an outer sleeve and an inner sleeve. The outer sleeve has a tissue-receiving window, and the inner sleeve has a distal end which cuts tissue as the inner sleeve is advanced past the window. The tissue is received into a lumen of the inner sleeve, and the inner sleeve lumen is typically enlarged in a proximal direction to reduce the tendency of resected tissue to lodge therein. The tissue displacement member is optionally provided at a distal end of the outer sleeve to further aid in dislodging tissue which becomes captured in a distal end of the inner sleeve of the lumen.
1. A method of resecting tissue, comprising:
advancing a tissue resecting device to a treatment site, the tissue resecting device comprising:
an outer sleeve including a side window opening into a lumen of the outer sleeve and a tissue engagement member extending proximally from a distal tip of the outer sleeve within the lumen, the outer sleeve including a first electrode having a first polarity; and
an inner sleeve positioned in the lumen of the outer sleeve, the inner sleeve including a tubular shaft and a second electrode at a distal end of the tubular shaft, the second electrode having a second polarity opposite the first electrode;
longitudinally reciprocating the inner sleeve relative to the outer sleeve such that the second electrode repeatedly moves across the side window from a proximal position to a distal position and back to the proximal position from the distal position, wherein in the distal position the second electrode extends distal of a proximal end of the tissue engagement member; and
applying an RF current between the first electrode and the second electrode as the second electrode moves across the side window from the proximal position to the distal position.
2. The method of claim 1 , further comprising:
forming plasma at a distal edge of the second electrode as the second electrode moves across the side window from the proximal position to the distal position.
3. The method of claim 2 , further comprising:
vaporizing tissue with the plasma at the distal end of the second electrode.
4. The method of claim 1 , wherein the second electrode surrounds the tissue engagement member in the distal position.
5. The method of claim 1 , further comprising:
pushing tissue proximally into a tissue extraction lumen of the tubular shaft of the inner sleeve with the tissue engagement member as the inner sleeve moves to the distal position.
6. The method of claim 5 , further comprising:
aspirating the tissue proximally through the tissue extraction lumen.
7. The method of claim 5 , further comprising:
collecting the tissue in a collection reservoir.
8. The method of claim 1 , wherein the tissue engagement member comprises a dielectric material.
9. The method of claim 8 , wherein the dielectric material is ceramic.
10. The method of claim 8 , wherein the dielectric material is polymeric.
11. The method of claim 1 , wherein the outer sleeve includes a dielectric material extending around a perimeter of the side window.
12. The method of claim 1 , wherein the tissue engagement member includes ribs and channels extending longitudinally.