An implantable lead for stimulating patient tissue includes a lead body. A jacket is disposed over at least a portion of a length of the lead body. The jacket has an outer surface and an opposing inner surface. At least a portion of the outer surface of the jacket forms at least a portion of an outer surface of the lead. At least a portion of the inner surface of the jacket is open to the lead body. The jacket defines apertures each extending completely through the jacket. Electrodes are disposed along a distal end of the lead body. Terminals are disposed along a proximal end of the lead body. Conductors electrically couple the electrodes to the terminals. Conductor insulation is disposed over each of the conductors. At least a portion of the conductor insulation is in fluid communication with the local environment external to the lead via the apertures.
