Systems and methods for making and using electrode or terminal extensions for coupling to leads of implantable electrical systems

A lead assembly for an implantable electrical stimulation system comprising:

• a lead configured and arranged for insertion into a patient, the lead comprising
• a lead body having a distal end, a proximal end, and a longitudinal length,
• a plurality of electrodes disposed along the distal end of the lead body, the plurality of electrodes arranged into at least one electrode array,
• a plurality of terminals disposed along the proximal end of the lead body, the plurality of terminals arranged into a plurality of terminal arrays, each terminal array comprising a plurality of the terminals, wherein the plurality of terminal arrays comprises a proximal-most terminal array and a medial terminal array axially-spaced-apart from one another along the longitudinal length of the lead body with the medial terminal array being disposed distal to the proximal-most terminal array along the longitudinal length of the lead body, and
• a plurality of conductors electrically coupling the plurality of electrodes to at least one of the plurality of terminals;
• and
• a terminal extension configured and arranged to electrically couple to the medial terminal array, the terminal extension comprising
• a terminal extension body having a first end and an opposing second end,
• a terminal extension connector disposed at the first end of the terminal extension body,
• a port defined in the terminal extension connector, the port having a first open end and an opposing second open end and forming a continuous passageway therebetween, the port configured and arranged to receive the medial terminal array and to permit the lead body to extend through both of the first open end and the opposing second open end when the medial terminal array is received by the port,
• a connector contact array comprising a plurality of connector contacts disposed within the port, the connector contact array configured and arranged to couple electrically with terminals of the medial terminal array when the medial terminal array is received by the port,
• a terminal extension terminal array comprising a plurality of terminals disposed along the second end of the terminal extension body, and
• a plurality of terminal extension conductors electrically coupling the connector contact array to the terminal extension terminal array.