A bone screw comprises a main body including a shank portion, a head portion attached to the shank portion, and a cap moveably attached to the head portion. The head portion includes a tool interface structure therein having a closed end portion, an open end portion and sidewall extending therebetween. A tool lock recess is provided in at least one of the sidewalls of the tool interface structure. The tool interface structure is accessible through an opening within an exterior surface of the cap.
