US Patent 7953497 Insertion stylet

A stylet is provided which has improved stiffness and buckling strength and can be easily manufactured at low cost. The stylet is comprised of a covering and a core, each of which have different mechanical properties. In one embodiment, the stylet is comprised of an outer tube and an inner rod with a circular cross-section, wherein the rod is inserted inside the tube. The tube can be made from a material which is more resistant to permanent deformation than the inner rod. The inner rod is made from a stiffer material which provides buckling strength. The combination of the stylet and associated stimulation lead may be used to make multiple insertions into body tissue.