A dynamic stabilization assembly includes a flexible inner cord, an outer spacer, and a pair of anti -torque and anti -shear sleeves located on either end of the spacer and rotationally fixed with respect to the spacer, each sleeve having at least one and up to a plurality of protrusions or radially directed ridges and grooves on an outer surface thereof. Bone screws cooperating with the sleeves include at least one aperture or a plurality of ridges and grooves for close cooperation and engagement with the ridges and grooves of the anti -torque/ant i -shear sleeves.
