Arthroscopic devices and methods
A medical device includes an elongated sleeve having a longitudinal axis, a proximal end and a distal end. A cutting member having sharp edges formed from a wear-resistant ceramic material is carried at the distal end of the elongated sleeve. A motor drive is coupled to the proximal end of the elongated sleeve to rotate the sleeve at cutting member at high speed to cut bone and other hard tissue. An electrode is carried in a surface portion of ceramic cutting member for cautery or radiofrequency ablation of tissue when the sleeve and cutting member are is a stationary position.
1. A medical device for removing tissue in a patient, comprising:
an elongated sleeve with a dielectric cutting member extending distally from a distal end of the elongated sleeve, wherein the dielectric cutting member comprises a ceramic member and a central channel;
a window with at least one sharp cutting edge in the dielectric cutting member;
an electrode carried by the dielectric cutting member circumferentially spaced-apart from the window, wherein the electrode has micropores therein that communicate with the central channel of the ceramic member and the negative pressure source;
a motor drive configured to couple to a proximal end of the elongated sleeve to rotate the dielectric cutting member.
2. The medical device of claim 1 , wherein the window opens to a central channel of the dielectric cutting member that communicates with an interior channel in the elongated sleeve connected to a negative pressure source.
3. The medical device of claim 1 , wherein the dielectric cutting member comprises a wear-resistant ceramic material.
4. The medical device of claim 1 , wherein the electrode is circumferentially spaced-apart from the window by 180°.
5. The medical device of claim 1 , wherein the elongated sleeve extends along a longitudinal axis and the at least one sharp cutting edge is aligned generally with the longitudinal axis.
6. The medical device of claim 1 , wherein the window has a second side that defines a second sharp cutting edge aligned generally with the longitudinal axis.
7. The medical device of claim 1 , wherein the micropores comprise channels having a diameter ranging between 10 micrometers and 100 micrometers.
8. The medical device of claim 1 , wherein the micropores comprise channels having a diameter ranging between 20 micrometers and 50 micrometers.
9. The medical device of claim 1 , wherein the electrode has a surface area ranging from 1 mm 2 to 10 mm 2 .
10. The medical device of claim 1 , wherein the electrode has a surface area ranging from 2 mm 2 to 5 mm 2 .
11. A device for removing tissue in a patient, said device comprising:
a shaft having a longitudinal axis and including (i) an outer sleeve having a distal region with an outer window and an axial bore therethrough and (2) an inner sleeve rotationally disposed in the axial bore of the outer sleeve;
a dielectric cutting member having a longitudinal axis carried at a distal end of the inner sleeve, wherein the dielectric cutting member has an inner window with at least one sharp cutting edge; and
an electrode disposed on an exterior surface of the cutting member so that the inner sleeve can be rotated relative to the outer sleeve to expose the electrode through the outer window of the outer sleeve, wherein the electrode has micropores therein that communicate with a central channel of the dielectric cutting member and a negative pressure source.
12. The medical device of claim 11 , wherein the cutting member is cylindrical and the inner window has two circumferentially spaced-apart edges wherein at least one of said two circumferentially spaced-apart edges carries or defines the at least one sharp cutting edge.
13. The medical device of claim 12 , wherein a second of the two circumferentially spaced-apart edges defines or carries a second sharp cutting edge.
14. The medical device of claim 11 , wherein the electrode is circumferentially spaced-apart from the at least one sharp cutting edge of the inner window.
15. The medical device of claim 11 , wherein the electrode is circumferentially spaced-apart 180° from the inner window.
16. The medical device of claim 11 , further comprising a motor drive configured to be detachably coupled to the shaft to rotate the inner sleeve and the cutting member relative to the outer sleeve.
17. The medical device of claim 16 , wherein the motor drive includes a controller configured for automatically stopping rotation of the inner sleeve and dielectric cutting member relative to the outer sleeve to position the electrode within said outer window.
18. The medical device of claim 16 , further comprising a rotational position sensor configured to sense relative rotational position information of the inner sleeve and the outer sleeve and deliver the relative rotational positional information to the controller, wherein the controller is configured to use the relative rotational positional information to position the electrode within said outer window.
19. The medical device of claim 11 , wherein the dielectric cutting member comprises an electrically insulating ceramic material.
20. The medical device of claim 19 , wherein the inner and outer sleeves of the shaft comprise an electrically conductive metal, further comprising an electrically insulating layer between an interior surface of the axial bore of the outer sleeve and an exterior surface of the inner sleeve.
21. The medical device of claim 20 , wherein the electrode is electrically coupled to the inner sleeve.
22. The medical device of claim 11 , wherein the micropores comprise channels having a diameter ranging between 10 micrometers and 100 micrometers.
23. The medical device of claim 11 , wherein the micropores comprise channels having a diameter ranging between 20 micrometers and 50 micrometers.
24. The medical device of claim 11 , wherein the electrode has a surface area ranging from 1 mm 2 to 10 mm 2 .
25. The medical device of claim 11 , wherein the electrode has a surface area ranging from 2 mm 2 to 5 mm 2 .