Patent ID: 8568418

Claim:
A surgical instrument comprising: an outer tube having a distal end, a proximal end and a cutting window near the distal end; an inner rotating member having a distal end, a proximal end and a cutting member near the distal end, the inner rotating member is rotatably disposed within the outer tube; a handpiece that is coupled to the inner rotating member and the outer tube near the proximal ends of the inner rotating member and the outer tube, the handpiece having a longitudinal axis; and a rotation sensor system including: a magnetic member provided on the inner rotating member near the proximal end of the inner rotating member; a magnetically permeable member provided on the outer tube near the proximal end of the outer tube; and a sensor provided on the handpiece and sensing magnetic flux of the magnetically permeable member adjacent to the sensor, wherein the magnetic member, the magnetically permeable member and the sensor are radially aligned with each other with respect to the longitudinal axis, with the magnetic member being disposed radially inward of the magnetically permeable member, and the magnetically permeable member being disposed radially inward of the sensor.