An apparatus and method of manufacture includes a helical wire coil and a core wire. The core wire has a first wire portion and a second wire portion. The first wire portion of the core wire extends through the helical wire coil. The second wire portion of the core wire is intertwined with the first helical wire coil to fixedly secure the core wire relative to the first helical wire coil. The core wire is formed from a first material that is non-extensible. The core wire is fixedly secured relative to a distal portion of the helical wire coil such that the core wire inhibits longitudinal elongation of the helical wire coil along a longitudinal coil axis.
