In one embodiment, a medical system includes a medical instrument includes an elongated shaft having a distal end, at least one cutting element disposed at a distal end of the shaft, a position-tracking transducer disposed at the distal end of the shaft, and electrically insulated from the shaft and the at least one cutting element, and at least one metal coagulation electrode disposed at least partially over the position-tracking transducer, which electrically isolates the at least one metal coagulation electrode from the shaft, a signal generator coupled to apply an electrical current to the at least one metal coagulation electrode, and processing circuitry configured to receive signals generated by the position-tracking transducer, and track a location of the distal end responsively to the received signals.
