Assessing cement injection behaviour in cancellous bone: An in vitro study using flow models

• Published in: Journal of biomaterials applications 2014-10, Vol.29 (4), p.582-594
• Main Authors: Bou-Francis, Antony, López, Alejandro, Persson, Cecilia, Hall, Richard M, Kapur, Nikil
• Format: Article
• Language: English
• Subjects: Biomedical materials; Bone cement; Bone Cements - chemistry; bone surrogates; Bones; Boundaries; cement flow behaviour; cement leakage; Cements; Chemistry, Pharmaceutical; Engineering Science with specialization in Materials Science; Humans; In Vitro Techniques; Injections; Materials Testing - instrumentation; Mathematical models; Models, Biological; Osteoporosis - therapy; Peak pressure; Rheology; Roundness; Shape; Spinal Fractures - therapy; Spinal Neoplasms - secondary; Spinal Neoplasms - therapy; Teknisk fysik med inriktning mot materialvetenskap; vertebral augmentation; Vertebroplasty - methods
• ISSN: 0885-3282; 1530-8022; 1530-8022
• DOI: 10.1177/0885328214537858

Understanding the cement injection behaviour during vertebroplasty and accurately predicting the cement placement within the vertebral body is extremely challenging. As there is no standardized methodology, we propose a novel method using reproducible and pathologically representative flow models to study the influence of cement properties on injection behaviour. The models, confined between an upper glass window and a lower aluminium plate, were filled with bone marrow substitute and then injected (4, 6 and 8 min after cement mixing) with commercially available bone cements (SimplexP, Opacity+, OsteopalV and Parallax) at a constant flow rate (3 mL/min). A load cell was used to measure the force applied on the syringe plunger and calculate the peak pressure. A camera was used to monitor the cement flow during injection and calculate the following parameters when the cement had reached the boundary of the models: the time to reach the boundary, the filled area and the roundness. The peak pressure was comparable to that reported during clinical vertebroplasty and showed a similar increase with injection time. The study highlighted the influence of cement formulations and model structure on the injection behaviour and showed that cements with similar composition/particle size had similar flow behaviour, while the introduction of defects reduced the time to reach the boundary, the filled area and the roundness. The proposed method provides a novel tool for quick, robust differentiation between various cement formulations through the visualization and quantitative analysis of the cement spreading at various time intervals.