Abstract: The elongated stabilization member comprises a composite rod (R) having a uniform cross-section essentially throughout its length. The rod (R) has at least first and second segments (A, B, C) each of which has a different modulus of elasticity. Preferably the rod (R) is comprised of plastic with carbon fibers disposed therein and said first and second segments (A, B, C) have different orientation densities of fibers or lengths to provide said different moduli of elasticity.

Abstract: A spinal fixation system that utilizes a composite rod to which polyaxial pedicle screw/tulip assemblies are secured, a screwdriver that permits independent threading of a guide member to the tulip and independent threading of the pedicle screw, together with interengaging conical surfaces that true the screwdriver with the pedicle screw. In preferred embodiments, the screwdriver includes an elongated drive shaft having a handle end for imparting rotation and a pedicle screw engaging end, a cylindrical guide member rotatably mounted about said drive shaft, a knob at one end of said guide member for rotating same and a threaded tulip engaging end at the other end thereof. A grip is preferably sleeved around the cylindrical drive member and is longitudinally movable between proximal and distal positions wherein its distal end uncovers and covers, respectively, the screw engaging unit.

Abstract: The elongated stabilization member comprises a composite rod (R) having a uniform cross-section essentially throughout its length. The rod (R) has at least first and second segments (A, B, C) each of which has a different modulus of elasticity. Preferably the rod (R) is comprised of plastic with carbon fibers disposed therein and said first and second segments (A, B, C) have different orientation densities of fibers or lengths to provide said different moduli of elasticity.