A method of surgically positioning an electrode array at a desired implantation location relative to a nerve. A temporary probe electrode is temporarily positioned adjacent to the nerve and at a location which is caudorostrally separate to the desired implantation location of the electrode array. The implanted position of the probe electrode is temporarily fixed relative to the nerve. During implantation of the electrode array, electrical stimuli are applied from one of the temporarily fixed probe electrode and the electrode array, to evoke compound action potentials on the nerve. Compound action potentials evoked by the stimuli are sensed from at least one electrode of the other of the temporarily fixed probe electrode and the electrode array. From the sensed compound action potentials a position of the electrode array relative to the nerve is determined.
