Apparatus and method for determining the relative position and orientation of neurostimulation leads

A method for performing a medical procedure using a plurality of electrodes implanted within a patient, comprising:

• measuring a first monopolar impedance between a first one of the electrodes and a return or reference electrode;
• measuring a second monopolar impedance between a second one of the electrodes and the return or reference electrode;
• measuring a multipolar impedance between the first electrode and the second electrode;
• and
• estimating an amplitude of a field potential at the second electrode based on the first and second monopolar impedances and the multipolar impedance.

A method for performing a medical procedure using a plurality of electrodes implanted within a patient, comprising:

• performing two of the following:
• (1) measuring a first monopolar impedance between a first one of the electrodes and a return or reference electrode, and measuring a second monopolar impedance between a second one of the electrodes and the return or reference electrode;
• (2) measuring a multipolar impedance between the first electrode and the second electrode;
• and (3) measuring a field potential at the second electrode;
• and
• estimating a remaining one of the (1) first and second monopolar impedances;
• (2) the multipolar impedance;
• and (3) the field potential based on the performance of the two measurements.