A lead assembly includes a lead with a distal end and a proximal end. The had includes a plurality of electrodes disposed at the distal end and a plurality of terminals disposed at the proximal end. The lead also defines at least one central lumen and a plurality of outer lumens. The central and outer lumens extend from the proximal end to the distal end such that the plurality of outer lumens extend laterally from the at least one central lumen. The lead further includes a plurality of conductive wires. Each conductive wire couples at least one of the plurality of electrodes electrically to at least one of the plurality of terminals. At least two conductive wires are disposed in each of the plurality of outer lumens.