The invention relates to a method of creating a curvilinear cavity within a vertebral body or other body structure. The invention also relates to devices that may be used to perform the steps to create the curvilinear cavity. One such device is a curved drill including a lever and cam sub assembly. The curved drill can include a spring assembly that controls the curvature of the drill. The lever and cam sub assembly can be provided to allow tension to be reduced in the spring assembly.
