A percutaneous path is created into a bone having an interior volume occupied, at least in part, by a cancellous bone, e.g., a vertebral body. An expandable structure is introduced into the cancellous bone by deployment of a tool through the percutaneous path into the cancellous bone. The expandable structure is expanded and the tool withdrawn, leaving the expandable structure expanded inside the cancellous bone. Expansion of the expandable structure within cancellous bone can, e.g., compact cancellous bone, and/or create a cavity in cancellous bone, and/or move fractured cortical bone.