 Kyphoplasty and vertebroplasty are types of surgery that are used to treat broken bones in the back, which may have been caused by cancer. Both procedures involve injecting a mixture of medical cement into the broken bones in the back. The cement is designed to harden and become a permanent part of the bone, supporting the bone like an internal cast that brings it back to its original shape. The amount of cement will vary from person to person, but it could be, for example, anywhere from a fraction of a teaspoon to a full teaspoon. 