Mechanical characterisation of three percutaneous vertebroplasty biomaterials

Percutanous vertebroplasty (PVP) is gaining popularity for the treatment of vertebral compression fractures. The need of obtaining low viscosity materials for injection through small bore needles and the necessity of visualising the fluid flow during injection have led users to the formulation of a number of ad-hoc recipes aimed at adapting PMMA cements for this use. Industry, on its part, has addressed these requirements by developing specific products for this application. This study aimed at providing a direct comparison of a wide range of mechanical properties between three commercially available biomaterials developed for PVP: two PMMA based materials, Osteopal V (Merck Biomaterial GMBH, Dermstedt, D) and Verterbroplastic (DePuy Acromed, Inc, MA, USA), and a Bis-GMA composite, Cortoss (Orthovita, PA, USA). Cortoss consistently exhibited higher values for compressive strength, bending modulus and shear strength to both Osteopal V and Vertebroplastic. The creep behaviour of Cortoss was also different from that of the two PMMA cements. PVP can take advantage from the development of new injectable biomaterials in response to the problems associated with the use of PMMA in a highly vascularised area such as the vertebral body. In addition careful modulation of the mechanical properties of the material has the potential to further improve the outcome of PVP, possibly reducing the risk of adjacent level fractures associated with the procedure