the invention is directed to an electrically sensing and stimulating outer sheath for ensuring accurate surgical placement of a microsensor or a microstimulator near a nerve in living tissue . the electrically sensing outer sheath may also be used to verify the function of the microstimulator or microstimulator during surgical placement but before the outer sheath is removed . in the event that the microstimulator is not optimally placed near the nerve , or if the microstimulator is malfunctioning , this can be determined prior to removal of the outer sheath , thus reducing the possibility of nerve or tissue damage that might be incurred during a separate operation to remove the microstimulator .