The invention relates to methods of creating and/or enlarging 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 and/or enlarge the curvilinear cavity. In various embodiments, an apparatus for creating and/or enlarging a curvilinear cavity includes a handle and a flexible shaft assembly including a cutting tip or blade, a flexible rotatable drive shaft, and a flexible, moveable and non-rotatable housing.
