Fig. 6

Comparisons of cement leakage between the kyphoplasty and vertebroplasty groups. Leakages of cement were classified into three different types [22]: type B, through the basivertebral vein; type S, through the segmental vein; and type C, through a cortical defect including three patterns in C-type leakage (i.e., paraspinal, intradiscal, and posterior). Kyphoplasty resulted in considerably less cement extravasation (29%) than vertebroplasty (77%). In our series, leakage into the spinal canal (C-posterior type leakage) is significant in the vertebroplasty group (14% in the vertebroplasty group to 0% in the kyphoplasty group)