Systems and methods for providing a cavity in an interior body region are described. In one described method, a shaft comprising an expansible portion configured to expand once beyond a distal end of a first cannula is inserted through the first cannula. The expansible portion is then expanded, thereby creating a cavity. While the expansible portion is expanded, a bone cement may be inserted into the cavity. The expansible portion may then be collapsed, and the shaft removed through the first cannula.