Surgical apparatus and method

Abstract

The apparatus comprises an implant 200, which may be a cochlear implant, having a plurality of electrodes, a memory 102 configured to store instructions and a processor 104 configured to execute the instructions. When executed the apparatus transmits to a pulse generator 110 an electrode operation signal 106 configured to generate a current pulse on a first pair of electrodes of the implant (202-208, fig 2), receive a first impedance signal 108a from a first measurement pair of electrodes due to interaction of the current pulse with the electrically conductive volume. Then receive a second impedance signal 108b from a second measurement pair of electrodes due to interaction with the electrically conductive volume. The first measurement pair of electrodes and the second measurement pair of electrodes are different. The processor then uses a predetermined mapping relationship to determine a distance between an electrode contact surface on the implant and a wall of the electrically conductive volume and output the determined distance. A surgical instrument for implant insertion is also disclosed. [Figure 1 to accompany the abstract]