title: Assessing cement injection behaviour in cancellous bone: an in vitro study using flow models.
abstract: 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.
authors.affiliation: School of Mechanical Engineering, University of Leeds, UK a.boufrancis@leeds.ac.uk.
authors.forename: Antony
authors.initials: A
authors.lastname: Bou-Francis
authors.affiliation: Department of Engineering Sciences, Uppsala University, Sweden.
authors.forename: Alejandro
authors.initials: A
authors.lastname: López
authors.affiliation: Department of Engineering Sciences, Uppsala University, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Persson
authors.affiliation: School of Mechanical Engineering, University of Leeds, UK.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Hall
authors.affiliation: School of Mechanical Engineering, University of Leeds, UK.
authors.forename: Nikil
authors.initials: N
authors.lastname: Kapur
mesh_terms: D001843:Bone Cements / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D006801:Humans; D066298:In Vitro Techniques; D007267:Injections; D008422:Materials Testing / Q000295:instrumentation; D008954:Models, Biological; D010024:Osteoporosis / Q000628:therapy; D012212:Rheology; D016103:Spinal Fractures / Q000628:therapy; D013125:Spinal Neoplasms / Q000556:secondary / Q000628:therapy; D054854:Vertebroplasty / Q000379:methods*
chemical_list: D001843:Bone Cements
keywords: Bone cement; bone surrogates; cement flow behaviour; cement leakage; vertebral augmentation