Neurostimulation leads with reduced current leakage

A method of manufacturing an implantable neurostimulation lead, the method comprising:

• providing a flexible tubular member from a first electrically nonconductive material, wherein the tubular member comprises a distal portion and a proximal portion, and wherein the tubular member comprises one or more distal apertures at the distal portion of the tubular member and one or more proximal apertures at the proximal portion of the tubular member;
• disposing one or more conductors around an elongate mandrel in a coiled manner;
• placing the elongate mandrel within an interior of the tubular member;
• mounting one or more electrodes along an exterior of the distal portion of the tubular member, the electrodes comprising a first electrically conductive material;
• mounting one or more connector interfaces along an exterior of the proximal portion of the tubular member, the connector interfaces comprising a second electrically conductive material;
• for each conductor, causing a distal end of the conductor to exit the distal portion of the tubular member via a respective distal aperture to couple with a respective electrode, and causing a proximal end of the conductor to exit the proximal portion of the tubular member via a respective proximal aperture to couple with a respective connector interface;
• inserting or injecting a first filler element into the interior of the tubular member to occupy at least a portion of one or more gaps in the interior of the tubular member resulting from the exit of one or more of the one or more conductors from the tubular member, wherein the first filler element comprises a second electrically nonconductive material;
• and
• removing the elongate mandrel.