A mechanical cutting device that makes use of mechanical (rotary) motion and suction to engage tissue also applies a cutting energy sufficient to vaporize the tissue. The rotation and suction are used to engage the tissue (sucking tissue into cutting windows when the cutting windows of inner and outer blades are aligned), and then the cutting member(s) function as an electrode(s) by having an electrical cutting signal applied thereto so that the cutting member(s) electrically cut the tissue as the cutting members relatively rotate. The electrical cutting signal is only applied as the windows become aligned up until the cutting of the tissue is completed. The cutting signal preferably is stopped after the cutting windows become misaligned. While the cutting windows are misaligned, a coagulation signal can be supplied to the cutting member so that the device functions as an electrocautery device.
