Methods and devices for augmenting bone, such as in performing vertebroplasty are disclosed. A bone cement injection needle is provided, having a laterally deflectable distal end. The distal end may be provided with one or two or more cavity creation elements, such as inflatable balloons. A cavity creation element may include one or more filament layers. Systems are also disclosed, including the steerable injection needle, introducer and stylet. The system may additionally include a cement delivery gun, one-time use disposable cement cartridges and a cement mixing chamber. Methods are also disclosed.