Vasoocclusive coil with biplex windings to improve mechanical properties

The vasoocclusive device for use in interventional therapy and vascular surgery adapted to be inserted into a portion of a vasculature, includes a vasoocclusive coil disposed about an inner reinforcement coil wherein said vasoocclusive coil is helically wound and the inner reinforcement coil forms a reverse helical winding opposite the vasoocclusive coil winding, thereby forming a biplex wound coil. The vasoocclusive device biplex winding provides improved mechanical properties to the device. An inner reinforcement stretch resistant member attached within the biplex windings limits coil stretchability.