 23. Pre-existing conditions contrary to either PVA or vertebroplasty, such as: a. Irreversible coagulopathy or bleeding disorder. Note regarding reversible coagulopathies: Subjects on coumadin or other anticoagulants may participate. Investigators should follow routine practices for perioperative discontinuation and re-initiation of anticoagulants; b. Any evidence of VB or systemic infection. 