Low modulus PMMA-based bone cement for the reduction of adjacent vertebral fractures after vertebroplasty

Vertebral augmentation employing polymethylmethacrylate (PMMA) bone cement is a widely used therapeutic technique for treating vertebral compression fractures. In this study, polydimethylsiloxane (PDMS)-enhanced PMMA bone cement (PDMS/PMMA) was developed to address the significant limitations associated with traditional PMMA bone cements in vertebroplasty: excessive exothermicity causing necrosis of normal bone tissues and high stiffness leading to fractures in adjacent vertebrae. The incorporation of PDMS into the PMMA bone cement results in consumption of the heat generated during polymerization, which prevents necrosis of surrounding tissue and speeds up the curing process of PDMS, showcasing the synergistic effects between PMMA and PDMS. The PDMS uniformly dispersed in the PMMA bone cement does not significantly alter the radiographic contrast of the cement. The ex vivo experiments conducted using osteoporotic porcine vertebrae demonstrated that vertebrae injected with low modulus PDMS/PMMA(10/90) exhibited a significant delay in adjacent bone fracture compared to those treated with PMMA alone. This study proposes that low modulus PMMA-based bone cement may serve as an advanced therapeutic material for vertebroplasty. STATEMENT OF SIGNIFICANCE: Vertebroplasty using PMMA bone cement often leads to secondary adjacent vertebral fractures due to its high stiffness and exothermic curing, which can damage surrounding bone tissue. In this study, we developed a PDMS-containing PMMA bone cement that significantly reduces curing temperature and stiffness while maintaining biocompatibility and radiopacity. The synergistic interaction between PDMS and PMMA helps minimize thermal necrosis and reduces the risk of adjacent vertebral fractures. Ex vivo tests using osteoporotic porcine vertebrae demonstrated that the low-modulus PDMS-containing PMMA bone cement significantly delayed adjacent fractures compared to conventional PMMA bone cement. This work presents a strategy to overcome long-standing complications of vertebroplasty and may contribute to safer and more effective treatment options for osteoporotic vertebral compression fractures.