Implantable leads permitting functional status monitoring

Abstract

An implantable lead assembly includes a lead body extending from a proximal end to a distal end having an intermediate portion therebetween, where the lead body includes an insulating layer. A conductor is disposed within the insulating layer and the insulating layer surrounds the conductor. An electrode is coupled to the lead body, and the electrode is in electrical communication with the conductor. At least one conductive sleeve is disposed within the insulating layer. The at least one conductive sleeve surrounds the conductor and is electrically isolated from the electrode. The at least one conductive sleeve has a first impedance value in a first condition.

1 . A method comprising:
 measuring a first impedance of an at least one conductive sleeve at a first time in an implantable lead assembly, the implantable lead assembly including a lead body having a conductor disposed therein, an electrode coupled to the lead body and in electrical communication with the conductor, an insulating layer surrounds the conductor, and the at least one conductive sleeve is disposed within the insulating layer and surrounds the conductor;   measuring a second impedance of the at least one conductive sleeve at a second time; and   sending a signal if the second impedance is within a predetermined range.   
     
     
         2 . The method of  claim 1 , further comprising:
 comparing the first impedance with the second impedance.   
     
     
         3 . The method of  claim 1 , further comprising:
 wearing away the insulating layer during an intermediate period between the first time and the second time.   
     
     
         4 . The method of  claim 1 , further comprising:
 coupling the implantable lead assembly to a pulse generator, wherein the pulse generator is in electrical communication with the at least one conductive sleeve.   
     
     
         5 . The method of  claim 4 , wherein measuring the first impedance and measuring the second impedance are performed by the pulse generator. 
     
     
         6 . The method of  claim 4 , further comprising:
 storing the impedance measurements within the pulse generator.   
     
     
         7 . The method of  claim 1 , further comprising:
 coupling a monitoring unit to a terminal disposed on the lead body wherein the monitoring unit is in electrical communication with the at least one conductive sleeve.   
     
     
         8 . The method of  claim 7 , wherein measuring the first impedance and measuring the second impedance are performed by the monitoring unit. 
     
     
         9 . The method of  claim 1 , wherein measuring the first impedance and measuring the second impedance includes measuring impedance at preprogrammed times. 
     
     
         10 . The method of  claim 1 , wherein measuring the first impedance and measuring the second impedance are performed intermittently.