Arthroscopic devices and methods
An elongated shaft assembly includes a rotatable inner cutting sleeve and a non-rotating outer sleeve. A window of the inner cutting sleeve is selectively rotatable within an opening of the non-rotating outer sleeve to cut tissue with a sharpened cutting blade when rotated in a first rotational direction and to cut tissue with an electrode when rotated in a second rotational direction.
1. A method of treating tissue comprising:
engaging a working end of a shaft assembly against a tissue interface, the working end including an outer sleeve having an opening in a distal end thereof and an inner sleeve having a cutting window, wherein a portion of the tissue interface is engaged by the cutting window when exposed in the opening;
rotating the inner sleeve in a first rotational direction relative to the outer sleeve to cut the portion of the tissue interface comprising hard tissue by advancing a cutting edge on one side of the cutting window into the tissue interface; and
rotating the inner sleeve in a second rotational direction opposite to the first rotational direction to cut the portion of the tissue interface comprising soft tissue with an energized electrode disposed proximate to an opposite side of the cutting window.
2. The method of claim 1 wherein rotating the inner sleeve in the first rotational direction shears hard tissue comprising bone.
3. The method of claim 1 wherein the soft tissue comprises at least one of muscle, nerve tissue, cartilage, meniscus, connective tissue, tendons, and ligaments.
4. The method of claim 1 wherein the tissue interface is submerged in a liquid or a liquid is directed at the tissue interface through a channel in the shaft assembly while engaging the working end and rotating the inner sleeve.
5. The method of claim 4 further comprising applying negative pressure to a passageway in the shaft assembly to remove cut tissue through the passageway.
6. The method of claim 1 further comprising attaching and detaching a motor to the shaft assembly, wherein the motor selectively rotates the inner shaft in the first and second rotational directions.
7. The method of claim 6 further comprising attaching and detaching a radiofrequency (RF) power supply to the shaft assembly, wherein the RF power supply selectively energizes the electrode.
8. The method of claim 7 wherein a controller is operatively attached to the motor and to the RF power supply and wherein said controller causes the RF power supply to deliver cutting current to the electrode when the motor rotates the inner sleeve in a cutting direction and not deliver cutting current to the electrode when the motor is not rotating the inner sleeve in the cutting direction.
9. The method of claim 1 further comprising delivering a cutting current to the electrode only while the electrode is being rotated in a cutting direction.
10. The method of claim 9 wherein cutting current is delivered to the electrode only during a selected arc of rotation of the inner sleeve.
11. The method of claim 9 wherein cutting current is delivered to the electrode during full rotation of the inner sleeve.
12. The method of claim 1 further comprising stopping rotation of the inner sleeve in a selected rotational position relative to the outer sleeve to align the inner sleeve and the outer sleeve in a selected orientation.
13. The method of claim 1 further comprising delivering a coagulating current to the electrode while the inner sleeve is stationary for coagulating tissue.