A method for forming a wire construct includes forming a groove in a polymer having a mouth that is narrower than a width of a deeper portion of the groove and placing a substantial length of wire in the groove, the wire having a larger cross-sectional dimension than the mouth of the groove. Encapsulant is placed over the polymer. The wire construct is to be used for implantable stimulation leads, such as a cochlear stimulation lead or a neurostimulation lead. Two wire constructs can be assembled to form a multilayer wire construct.