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

Abstract

A method for determining whether the relative position of electrodes used by a neurostimulation system has changed within a patient comprises determining the amplitude of a field potential at each of at least one of the electrodes, determining if a change in each of the determined electric field amplitudes has occurred, and analyzing the change in each of the determined electric field amplitudes to determine whether a change in the relative position of the electrodes has occurred. Another method comprises measuring a first monopolar impedance between a first electrode and a reference electrode, measuring a second monopolar impedance between second electrode and the reference electrode, measuring a bipolar impedance between the first and second electrodes, and estimating an amplitude of a field potential at the second electrode based on the first and second monopolar impedances and the bipolar impedance.

1 . (canceled) 
     
     
         2 . A method, comprising:
 determining a relative position of a first implanted lead with respect to a second implanted lead,   
       wherein the first lead has a first set of at least two in-line electrodes on the first lead and the second lead has a second set of at least two in-line electrodes on the second lead, wherein each electrode in the first set and each electrode in the second set are capable of being independently activated;
 wherein the determining the relative position of the first implanted lead with respect to the second lead includes determining a relative position of each of the at least two electrodes in the first set to each of the at least two electrodes in the second set by delivering electrical energy to the corresponding electrode in the first set and determining at least one electrical parameter for each of the at least two electrodes in the second set and using the determined at least one electrical parameter to determine the position of the corresponding electrode in the first set relative to each of the at least two electrodes in the second set. 
 
     
     
         3 . The method of  claim 2 , wherein the determining relative positions is intermittently performed multiple times in the patient. 
     
     
         4 . The method of  claim 2 , wherein determining the at least one electrical parameter includes measuring at least one interelectrode impedance. 
     
     
         5 . The method of  claim 2 , wherein determining the at least one electrical parameter includes measuring at least one field potential. 
     
     
         6 . The method of  claim 2 , wherein determining the at least one electrical parameter includes estimating at least one field potential. 
     
     
         7 . The method of  claim 2 , further comprising displaying the determined relative position of the first implanted lead with respect to the second implanted lead. 
     
     
         8 . The method of  claim 2 , further comprising determining whether at least one of the implanted leads has migrated relative to at least one other of the implanted leads. 
     
     
         9 . The method of  claim 7 , further comprising initiating an action when the at least one of the implanted leads has migrated relative to the at least one other of the implanted leads. 
     
     
         10 . A non-transitory machine-readable medium including instructions, which when executed by a machine, cause the machine to perform a process comprising:
 determining a relative position of a first implanted lead with respect to a second implanted lead,   
       wherein the first lead has a first set of at least two in-line electrodes on the first lead and the second lead has a second set of at least two in-line electrodes on the second lead, wherein each electrode in the first set and each electrode in the second set are capable of being independently activated;
 wherein the determining the relative position of the first implanted lead with respect to the second lead includes determining a relative position of each of the at least two electrodes in the first set to each of the at least two electrodes in the second set by delivering electrical energy to the corresponding electrode in the first set and determining at least one electrical parameter for each of the at least two electrodes in the second set and using the determined at least one electrical parameter to determine the position of the corresponding electrode in the first set relative to each of the at least two electrodes in the second set. 
 
     
     
         11 . The non-transitory machine-readable medium of  claim 10 , wherein determining the at least one electrical parameter includes measuring at least one interelectrode impedance. 
     
     
         12 . The non-transitory machine-readable medium of  claim 10 , wherein determining the at least one electrical parameter includes measuring at least one field potential. 
     
     
         13 . The non-transitory machine-readable medium of  claim 10 , wherein determining the at least one electrical parameter includes estimating at least one field potential. 
     
     
         14 . The non-transitory machine-readable medium of  claim 10 , further comprising displaying the determined relative position of the first implanted lead with respect to the second implanted lead. 
     
     
         15 . The non-transitory machine-readable medium of  claim 10 , wherein the determining relative positions is intermittently performed multiple times in the patient 
     
     
         16 . A system configured for use with implanted leads, the system comprising:
 a pulse generator and a programmer configured to program the pulse generator, wherein the programmer is further configured to:   determine a relative position of a first implanted lead with respect to a second implanted lead,   
       wherein the first lead has a first set of at least two in-line electrodes on the first lead and the second lead has a second set of at least two in-line electrodes on the second lead, wherein the pulse generator is configured to independently activate each electrode in the first set and each electrode in the second set;
 wherein the relative position of the first implanted lead with respect to the second lead is determined by determining a relative position of each of the at least two electrodes in the first set to each of the at least two electrodes in the second set by delivering electrical energy to the corresponding electrode in the first set and determining at least one electrical parameter for each of the at least two electrodes in the second set and using the determined at least one electrical parameter to determine the position of the corresponding electrode in the first set relative to each of the at least two electrodes in the second set. 
 
     
     
         17 . The system of  claim 16 , wherein the relative positions of the first implanted lead with respect to a second implanted lead is intermittently performed multiple times in the patient 
     
     
         18 . The system of  claim 16 , further comprising determining whether at least one of the implanted leads has migrated relative to at least one other of the implanted leads. 
     
     
         19 . The system of  claim 16 , further comprising initiating an action when the at least one of the implanted leads has migrated relative to the at least one other of the implanted leads. 
     
     
         20 . The system of  claim 16 , wherein determining the at least one electrical parameter includes measuring at least one interelectrode impedance, measuring at least one field potential, or estimating at least one field potential. 
     
     
         21 . The system of  claim 16 , wherein the system is configured to display the determined relative position of the first implanted lead with respect to the second implanted lead.