A method of making a spacer cage is disclosed. The method may include providing a tube having an outer diameter, a first second, a second section and a middle section having a first end connected to the first section and a second end connected to the second section, cutting the middle section to form strut elements of the spacer cage and cutting a plurality of longitudinal slits in the first and second sections to allow radial expansion of the first and second sections, expanding the tube using a mandrel, heat setting the tube while on the mandrel, and subsequent the heat setting, removing the first and second sections from the tube.