Percutaneous vertebroplasty in sheep: testing a novel mesoporous bioactive glass/calcium sulphate cement

Abstract

Polymethylmethacrylate (PMMA) based cements are widely used for vertebroplasty. However, PMMA has disadvantages. To develop an innovative, resorbable and injectable composite cement – SpineGhost –, type III α-calcium sulphate hemihydrate was used as the bioresorbable matrix, while spraydried mesoporous bioactive particles were added for high bioactivity, and a zirconia containing glassceramic was added to increase radiopacity. An injectable paste was obtained by adding water. The purpose of the present work was to test in vivo the suitability of the novel injectable cement for percutaneous vertebroplasty. A sheep study was conducted, following a previously developed animal model. The paste was percutaneously injected in bone defects manually drilled percutaneously in L4 vertebral bodies of eight mature Merino sheep (Group B). A control group of eight sheep was injected with a known commercial calcium sulphate-based biphasic cement (Group A). Micro-CT overall mean tissue volume, an indicator of the injected defect volume, was 1.217±0.235 mL. All sheep survived and completed the 6-month implantation period. After sacrifice the samples were assessed by micro-CT and by histological, histormophometric and immunohistological studies. Cement resorption and new bone formation were observed in all samples with no signs of infection or inflammation.