<qa>  What is the name of the biomaterial that is used to describe the vertebroplasty procedureEligible patients with painful osteoporotic compression fractures of the spine are divided into two groups. Each enrolled patient will have the vertebroplasty procedure; however one group of patients will have the vertebroplasty procedure using polymethylmethacrylate PMMA a Food and Drug Administration FDA-approved bone cement and the other group of patients will have the vertebroplasty procedure using a relatively new investigational biomaterial called Cortoss. 