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The effect of glassy carbon and cancellous bone admixture on performance and thermal properties of acrylic bone cements

Choryłek P., Postawa P.

Archives of Materials Science and Engineering

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2020

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Vol. 104, nr 1

30--40

EN

Purpose: of the research is to physically modify the composition of bone cements with glassy carbon and cancellous bone to improve its performance, reduce polymerization temperature and reduce the ability of cements the effect of admixture on the phenomenon of relaxation. Design/methodology/approach: SpinePlex bone cement was modified with glassy carbon powder with 20-50 pm granulation with Maxgraft®. Maxgraft cancellous bone has been ground to 20-50 pm grains. Samples of unmodified cements (reference) and modified with glassy carbon and cancellous bone were prepared for the tests. The glassy carbon powder and ground cancellous bone were premixed with the cement copolymer powder, and then the premix prepared this way was spread in a liquid monomer. To delay the polymerization process, all components were cooled before mixing to 15°C. The addition of glassy carbon was 0.4 g and the addition of cancellous bone was 0.2 g per 20 g of cement powder, i.e. about 1.96% by mass. Polymerization temperature, relaxation and differential scanning calorimetry tests were performed on the samples made. Findings: Additives used allow: to reduce the polymerization temperature, as well as rheological properties. During the studies it was found that the additive which can meet the requirements is glassy carbon in form of powder and cancellous bone. Research limitations/implications: The results presented in the publication require further advanced research, which will be the subject of further modification attempts by the research team. Practical implications: The conducted tests showed a significant effect of glassy carbon as a modifier on the mechanical properties of cement after its solidification, but also on the course of the polymerization process. Temperature registration tests during crosslinking, tests of mechanical properties (behaviour of cement samples under load) and DSC differential scanning calorimetry analysis confirmed that the addition of glassy carbon had an effect on each of these aspects. Originality/value: The original in these studies is the possibility to improve fundamental properties of the selected bone cements by using different than commonly used additives.

2

Comparison of selected properties of cements modified with glassy carbon and cancellous bone

Choryłek P.

Archives of Materials Science and Engineering

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2020

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Vol. 105, nr 1

31--41

EN

Purpose: The aim of this manuscript was to study and analyse the properties of bone cement (VertaPlex) before and after modification with glassy carbon (Alfa Aesar) and human bone (MaxGraft). Design/methodology/approach: To achieve the assumed goal, a series of samples was made - five samples for each mixture, where: 5 bone cement samples, 5 bone cement samples mixed with 20-50 μm glassy carbon in the ratio of 1 g carbon per 40 g of cement, and 5 samples of bone cement mixed with 20-50 μm glassy carbon and human bone in the ratio of 1 g of carbon per 40 g of cement and 0.4 g of bone per 40 g of cement. The produced samples (4 for each mixture, 1 was the reference sample) were subjected to tests - compression test, microscopic observations with a 3D microscope, surface profile tests and hardness tests. Findings: The study has shown that modifications with glassy carbon and bone change the mechanical properties, as well as the strength of the samples. Compression tests have shown that the material without admixtures is characterized by the highest compressive strength and the doping of the glassy carbon itself makes the material more brittle. A significant increase in hardness was also observed for samples with glassy carbon and bones after the pressing process. Practical implications: The study was made synthetically, without taking into account the effect of the environment of body fluids and the human body temperature. This study is an introduction to further considerations where samples for which these conditions will be applied are currently being prepared. Originality/value: For commercial use, in treatment of patients, cements modified with glassy carbon and bone glassy carbon have not been used so far. Due to the prerequisites of a positive effect of glassy carbon addition on osseointegration and biocompatibility, the study in this area has been undertaken.

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Analiza numeryczna segmentu ruchowego odcinka lędźwiowego kręgosłupa człowieka w przypadku wystąpienia kręgozmyku

Joszko Kamil, Machnia Karolina

Aktualne Problemy Biomechaniki

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2020

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z. 20

45--53

PL

Celem przeprowadzonych badań była ocena obciążeń występujących w odcinku lędźwiowym kręgosłupa człowieka na poziomie L4-L5 dla schorzenia kręgozmyku. Modele numeryczne poszczególnych części segmentu ruchowego zostały wysegmentowane w oparciu o zdjęcia tomografii komputerowej. Następnie w oprogramowaniu MES przeprowadzono analizę numeryczną modelu kręgosłupa fizjologicznie prawidłowego oraz modeli z różnymi stopniami kręgozmyku w następującej skali: 4 mm, 6 mm, 8 mm, 10 mm oraz 12 mm.

EN

The research carried out a numerical analysis of the loads occurring in the lumbar spine at the L4-L5 level. The project started with modeling the spine diseases in the Inventor 2018 software for different values of spondylolisthesis. In ANSYS Workbench 2013, numerical simulations were performed: analysis of a physiologically correct model, analysis of the mathematical model of the spine with various degrees of spondylolisthesis (4 mm, 6 mm, 8 mm, 10 mm and 12 mm). Models were verified on the basis of literature data.

4

Vertebroplasty and kyphoplasty - advantages and disadvantages used bone cement of PMMA

Choryłek P.

Journal of Achievements in Materials and Manufacturing Engineering

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2019

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Vol. 92, nr 1-2

36--49

EN

Purpose: This paper is a review of literature where the analyses of the commonly used bone cements were carried out especially: methods of manufacturing, surgical techniques, mechanical properties, biocompatibility studies as well as possibility of improvement some properties by using additives. Design/methodology/approach: The aim of this publication is the analysis of the state of knowledge and treatment methods on compression fractures, approximation of the specifics of compression fractures, presentation of minimally invasive percutaneous surgical techniques, description of features of the most common used bone cement on matrix Poly(methyl methacrylate) – (PMMA) and presentation cement parameters which affect potential postoperative complications. Findings: In considering to review of actual state of knowledge there is a need to find the additives which allow: to reduce the polymerization temperature, improve the biocompatibility as well as mechanical properties. During the studies it was found that the additive which can meet the requirements is glassy carbon in form of powder. Practical implications: Discussion allows to prepare samples during practical work with new kind additives in composite with bone cement as matrix. Originality/value: The original in this discussion is the possibility to improve fundamental properties of the selected bone cements by using different than commonly used additives.

5

Changes of structure and properties of PMMA-based bone cements with hydroxyapatite after degradation process

Laska-Leśniewicz Anna, Raczyńska Małgorzata, Wrotniak Maciej, Sobczyk-Guzenda Anna

Engineering of Biomaterials

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2019

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Vol. 22, no. 151

9--16

EN

PMMA-based bone cements are commonly used for implant fixation or as bone void fillers. Hydroxyapatite added as a filler to bone cement may positively affect the final properties of the material, in particular its biological properties. In this study, the preparation of poly(methyl methacrylate)-based bone cements with incorporated hydroxyapatite (HAp) is reported. The purpose of this article is to examine the proper-ties of bone cements enriched with HAp filler (the concentration of 3wt% and 6wt%) and reveal the changes in the composites properties (chemical structure, surface morphology and distribution of HAp in the composite matrix, moisture absorption, hardness in Shore D scale) during the long-term incubation in the PBS (phosphate-buffered saline) solution at 37°C. The incubation lasted up to 21 days, but only the period when the changes actually occurred was analysed. The studies have shown that the samples containing HAp absorb more moisture and have a lower hardness. These characteristics vary depending on the concentration of HAp. There is no elution of HAp and ZrO2 from the composite during the incubation. The surface morphology and chemical structure do not change during long-term studies. The obtained bone cements are characterized by high stability in the PBS solution.

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Preoperative planning and post-operative estimation of vertebroplasty using CT/CAD/CAE systems

Skoworodko J., Skalski K., Cejmar W., Kwiatkowski K.

Acta of Bioengineering and Biomechanics

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2008

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Vol. 10, nr 2

15-22

EN

The aim of the work was to determine the stiffness of vertebral bodies after vertebroplasty by means of radiological examination (CT), computer-aided design (CAD) and computer-aided engineering (CAE) systems. Twenty six patients with angiomata in vertebrae have been examined. A vertebra with pathological changes has been modelled twice, i.e. before operation and after the process of vertebral body filling with cement. The processing of CT images for the purposes of generation of 3D vertebral body models using Mimics software is also shown. In the analysis, non-homogeneous material properties of bone in the analysed areas are taken into consideration. Some problems related to the determination of non-homogeneous areas of particular material properties are discussed. FEM analyses described in the paper yielded the distributions of the stresses, strains and displacements in vertebral bodies. The stiffnesses of healthy vertebral bodies, bodies with pathological changes and bodies with bone cement injected were compared. The usefulness of the results obtained from the analyses of vertebral body stiffness for medical application in vertebroplasty was emphasised. The method presented above allows us to put forward a different approach to the problem consisting in individual examination of each patient and planning the surgery according to the case by case conditions. The computer-aided approach, using CT/CAD/CAE system, proposed above allows both improving the surgery performance and post-operative control of the patient condition.