A needle-mounted balloon system can include a cannula and a stylet. The cannula may include a handle and an outer sheath, and the outer sheath may be configured to retract and expose at least a portion of an expandable member. The stylet may include a stylet needle and a sharp distal tip portion. The stylet needle may be used to insert the system into a body structure, after which the stylet may be disengaged from the cannula. The expandable member may then be exposed and inflated to create a space in the body structure. Filler material may be injected through the cannula to the open space in an effort to stabilize an injured or otherwise destabilized portion of the body structure.
