The present invention addresses rod rotation and slippage inside the tulip rod channel(s), as well as forcible rod bending as the spine and musculature bias towards a deformity, for example. The present invention provides a stabilization rod that, fundamentally, includes at least one flat surface on at least one side of the construct, this flat surface engaging a corresponding flat surface associated with the head body, set screw, or locking cap. Multiple flat surfaces may, of course, be used. The stabilization rod may also include one or more ridges and/or one or more keyed channels that is/are engaged by the head body, set screw, or locking cap.
