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Calik J, Zawada T, Sauer N, Bove T. High Intensity Focused Ultrasound (20 MHz) and Cryotherapy as Therapeutic Options for Granuloma Annulare and Other Inflammatory Skin Conditions. Dermatol Ther (Heidelb) 2024:10.1007/s13555-024-01163-7. [PMID: 38703308 DOI: 10.1007/s13555-024-01163-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 04/08/2024] [Indexed: 05/06/2024] Open
Abstract
INTRODUCTION In dermatology, inflammatory skin conditions impose a substantial burden worldwide, with existing therapies showing limited efficacy and side effects. This report aims to compare a novel immunological activation induced by hyperthermic 20 MHz high intensity focused ultrasound (HIFU) with conventional cryotherapy. The bioeffects from the two methods are initially investigated by numerical models, and subsequently compared to clinical observations after treatment of a patient with the inflammatory disease granuloma annulare (GA). METHODS Clinical responses to moderate energy HIFU and cryotherapy were analysed using numerical models. HIFU-induced pressure and heat transfer were calculated, and a three-layer finite element model simulated temperature distribution and necrotic volume in the skin. Model output was compared to 22 lesions treated with HIFU and 10 with cryotherapy in a patient with GA. RESULTS Cryotherapy produced a necrotic volume of 138.5 mm3 at - 92.7 °C. HIFU at 0.3-0.6 J/exposure and focal depths of 0.8 or 1.3 mm generated necrotic volumes up to only 15.99 mm3 at temperatures of 68.3-81.2 °C. HIFU achieved full or partial resolution in all treated areas, confirming its hyperthermic immunological activation effect, while cryotherapy also resolved lesions but led to scarring and dyspigmentation. CONCLUSION Hyperthermic immunological activation of 20 MHz HIFU shows promise for treating inflammatory skin conditions as exemplified by GA. Numerical models demonstrate minimal skin necrosis compared to cryotherapy. Suggested optimal HIFU parameters are 1.3 mm focal depth, 0.4-0.5 J/exposure, 1 mm spacing, and 1 mm margin. Further studies on GA and other inflammatory diseases are recommended.
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Affiliation(s)
- Jacek Calik
- Old Town Clinic, Wszystkich Świętych 2a, 50-127, Wrocław, Poland
- Department of Clinical Oncology, Wroclaw Medical University, 50-556, Wrocław, Poland
| | - Tomasz Zawada
- TOOsonix A/S, Agern Allé 1, 2970, Hoersholm, Denmark.
| | - Natalia Sauer
- Old Town Clinic, Wszystkich Świętych 2a, 50-127, Wrocław, Poland
- Faculty of Pharmacy, Wroclaw Medical University, 50-556, Wrocław, Poland
| | - Torsten Bove
- TOOsonix A/S, Agern Allé 1, 2970, Hoersholm, Denmark
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Ashkanfar A, Toh SMS, English R, Langton DJ, Joyce TJ. The impact of femoral head size on the wear evolution at contacting surfaces of total hip prostheses: A finite element analysis. J Mech Behav Biomed Mater 2024; 153:106474. [PMID: 38447273 DOI: 10.1016/j.jmbbm.2024.106474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/08/2024]
Abstract
Total Hip Arthroplasty has been a revolutionary technique in restoring mobility to patients with damaged hip joints. The introduction of modular components of the hip prosthesis allowed for bespoke solutions based on the requirements of the patient. The femoral stem is designed with a conical trunnion to allow for assembly of different femoral head sizes based on surgical requirements. The femoral head diameters for a metal-on-polyethylene hip prosthesis have typically ranged between 22 mm and 36 mm and are typically manufactured using Cobalt-Chromium alloy. A smaller femoral head diameter is associated with lower wear of the polyethylene, however, there is a higher risk of dislocation. In this study, a finite element model of a standard commercial hip arthroplasty prosthesis was modelled with femoral head diameters ranging from 22 mm to 36 mm to investigate the wear evolution and material loss at both contacting surfaces (acetabular cup and femoral stem trunnion). The finite element model, coupled with a validated in-house wear algorithm modelled a human walking for 10 million steps. The results have shown that as the femoral head size increased, the amount of wear on all contacting surfaces increased. As the femoral head diameter increased from 22 mm to 36 mm, the highly cross-linked polyethylene (XLPE) volumetric wear increased by 61% from 98.6 mm3 to 159.5 mm3 while the femoral head taper surface volumetric wear increased by 21% from 4.18 mm3 to 4.95 mm3. This study has provided an insight into the amount of increased wear as the femoral head size increased which can highlight the life span of these prostheses in the human body.
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Affiliation(s)
- Ariyan Ashkanfar
- School of Engineering, Liverpool John Moores University, Liverpool, UK
| | | | - Russell English
- School of Engineering, Liverpool John Moores University, Liverpool, UK
| | | | - Thomas J Joyce
- School of Engineering, Newcastle University, Newcastle Upon Tyne, UK
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Qasim M, López Picazo M, Ruiz Wills C, Noailly J, Di Gregorio S, Del Río Barquero LM, Malouf Sierra J, Humbert L. 3D-DXA Based Finite Element Modelling for Femur Strength Prediction: Evaluation Against QCT. J Clin Densitom 2024; 27:101471. [PMID: 38306806 DOI: 10.1016/j.jocd.2024.101471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 01/10/2024] [Accepted: 01/18/2024] [Indexed: 02/04/2024]
Abstract
Osteoporosis is characterised by the loss of bone density resulting in an increased risk of fragility fractures. The clinical gold standard for diagnosing osteoporosis is based on the areal bone mineral density (aBMD) used as a surrogate for bone strength, in combination with clinical risk factors. Finite element (FE) analyses based on quantitative computed tomography (QCT) have been shown to estimate bone strength better than aBMD. However, their application in the osteoporosis clinics is limited due to exposure of patients to increased X-rays radiation dose. Statistical modelling methods (3D-DXA) enabling the estimation of 3D femur shape and volumetric bone density from dual energy X-ray absorptiometry (DXA) scan have been shown to improve osteoporosis management. The current study used 3D-DXA based FE analyses to estimate femur strength from the routine clinical DXA scans and compared its results against 151 QCT based FE analyses, in a clinical cohort of 157 subjects. The linear regression between the femur strength predicted by QCT-FE and 3D-DXA-FE models correlated highly (coefficient of determination R2 = 0.86) with a root mean square error (RMSE) of 397 N. In conclusion, the current study presented a 3D-DXA-FE modelling tool providing accurate femur strength estimates noninvasively, compared to QCT-FE models.
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Elzeadani M, Bompa DV, Elghazouli AY. Data on the axial response of steel tubes infilled with rubberised alkali-activated concrete. Data Brief 2024; 53:110172. [PMID: 38375142 PMCID: PMC10875217 DOI: 10.1016/j.dib.2024.110172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/26/2024] [Accepted: 02/02/2024] [Indexed: 02/21/2024] Open
Abstract
The presented data cover experimental and numerical axial load-shortening results of steel tubes infilled with rubberised alkali-activated concrete. The experimental data are obtained from 36 concrete filled steel tube specimens with circular and square cross-sections, length-to-diameter/width ratios of 2 and 4, and three different rubber contents in the concrete infill. The data from the numerical assessment cover the axial load-shortening response of over 300 finite element models. These cover a wide range of concrete infill strengths and rubber contents, steel tube grades, specimen widths, and steel tube wall thicknesses. Detailed descriptions of the material and methods, experimental testing, and numerical modelling procedures are also provided. The data reported herein supports the discussion in the research article "Axial compressive behaviour of composite steel elements incorporating rubberised alkali-activated concrete," and in the case of the numerical parametric assessment, give for the first time the full axial load-shortening response of all the models considered.
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Affiliation(s)
- Mohamed Elzeadani
- Department of Civil and Environmental Engineering, Imperial College London, London SW7 2BU, UK
| | - Dan V. Bompa
- Department of Civil and Environmental Engineering, University of Surrey, Guildford GU2 7XH, UK
| | - Ahmed Y. Elghazouli
- Department of Civil and Environmental Engineering, Imperial College London, London SW7 2BU, UK
- Department of Civil and Environmental Engineering, Hong Kong Polytechnic University, Hong Kong
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Casafont M, Marimon F, Bové O, Ferrer M, Centelles X. Local buckling of cold-formed steel trapezoidal sheets: Data for finite element model validation. Data Brief 2024; 53:110075. [PMID: 38317733 PMCID: PMC10838704 DOI: 10.1016/j.dib.2024.110075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/21/2023] [Accepted: 01/15/2024] [Indexed: 02/07/2024] Open
Abstract
Data is provided from a validation example for a finite element model of a cold-formed steel trapezoidal sheet. The sheet is subjected to bending, failing due to local buckling. The numerical model and the validation procedure are carried out according to the new Eurocode 3 prEN1993-1-14 Design assisted by finite element analysis. Detailed information concerning all aspects needed to reproduce the example is included: (i) the nominal and measured values of the sheet geometry; (ii) the measured material properties of the steel; (iii) the test setup of the validation experiments; (iv) the experimental results; (v) a complete description of the finite element model and solution procedure; and (vi) the finite element results. Additionally, data related to sensitivity studies on the numerical model is also presented, including the effect of the model domain, meshing, and imperfections (shape, magnitude, direction and combinations). Overall, the article aims to provide data and guidance to designers and researchers validating similar numerical models.
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Affiliation(s)
- Miquel Casafont
- Research Group in Structures and Mechanics of Materials (REMM), Department of Strength of Materials and Structural Engineering, Universitat Politècnica de Catalunya (BarcelonaTech-UPC), Avinguda Diagonal 647 09028, Spain
| | - Frederic Marimon
- Research Group in Structures and Mechanics of Materials (REMM), Department of Strength of Materials and Structural Engineering, Universitat Politècnica de Catalunya (BarcelonaTech-UPC), Avinguda Diagonal 647 09028, Spain
| | - Oriol Bové
- Research Group in Structures and Mechanics of Materials (REMM), Department of Strength of Materials and Structural Engineering, Universitat Politècnica de Catalunya (BarcelonaTech-UPC), Avinguda Diagonal 647 09028, Spain
| | - Miquel Ferrer
- Research Group in Structures and Mechanics of Materials (REMM), Department of Strength of Materials and Structural Engineering, Universitat Politècnica de Catalunya (BarcelonaTech-UPC), Avinguda Diagonal 647 09028, Spain
| | - Xavier Centelles
- Research Group in Structures and Mechanics of Materials (REMM), Department of Strength of Materials and Structural Engineering, Universitat Politècnica de Catalunya (BarcelonaTech-UPC), Avinguda Diagonal 647 09028, Spain
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Pan J, Wang J, Evernden M, Gu Y. Dataset on sinusoidally stiffened 3D printed steel plated structures. Data Brief 2024; 53:110193. [PMID: 38419770 PMCID: PMC10900762 DOI: 10.1016/j.dib.2024.110193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 02/01/2024] [Accepted: 02/08/2024] [Indexed: 03/02/2024] Open
Abstract
The paper reports a series of experimental and numerical data of destructive stub column tests on additively manufactured steel parts stiffened by surface sinusoidal wave patterns. The specimens were made in 316L stainless steel and manufactured by selective laser melting (SLM). The experimental tests covered five tensile coupon tests, fourteen square hollow section (SHS) stub column tests and measurements of geometric imperfections of the stub columns. Numerical models incorporating the measured material and geometric properties were developed and analysed via GMNIA approach. The validity of the numerical models is demonstrated by their accurate replications of the load-end shortening responses of the tested specimens. The reported dataset will contribute to the stability design and characterisation of thin-walled steel plated structures with advanced stiffening patterns.
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Affiliation(s)
- Jingbang Pan
- Department of Architecture and Civil Engineering, University of Bath, Bath BA2 3GE, UK
| | - Jie Wang
- Department of Architecture and Civil Engineering, University of Bath, Bath BA2 3GE, UK
| | - Mark Evernden
- Department of Architecture and Civil Engineering, University of Bath, Bath BA2 3GE, UK
| | - Yang Gu
- Department of Architecture and Civil Engineering, University of Bath, Bath BA2 3GE, UK
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Walport F, Zhu Y, Yun X, Gardner L. Experimental and numerical datasets for benchmark tests on high strength steel I-section frames. Data Brief 2024; 53:110049. [PMID: 38317731 PMCID: PMC10838695 DOI: 10.1016/j.dib.2024.110049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/29/2023] [Accepted: 01/04/2024] [Indexed: 02/07/2024] Open
Abstract
This data article presents experimental and numerical datasets for eight fixed-base, single storey, unbraced high strength steel welded I-section frames subjected to in-plane horizontal and vertical loading. A detailed description of the full-scale frame testing programme is provided in the related research article 'Benchmark tests on high strength steel frames'. The experimental dataset can be used to steer future research in full-scale structural testing and provide benchmark results that are suitable for the validation of finite element models and the development of system-level design approaches. In addition to the benchmark experimental frame data, all necessary details and data for shell finite element (FE) model validation using geometrically and materially nonlinear analysis (GMNIA) is presented. The general purpose FE software Abaqus was used. The dataset can be used as an illustrative example of GMNIA validation in accordance with EN 1993-1-14 with all relevant data for reproducibility provided.
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Affiliation(s)
- Fiona Walport
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
| | - Yufei Zhu
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
- School of Civil Engineering, Shanghai Normal University, Shanghai, PR China
| | - Xiang Yun
- Department of Civil Engineering, University of Bristol, Bristol, UK
| | - Leroy Gardner
- Department of Civil and Environmental Engineering, Imperial College London, London, UK
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Damians IP, Moncada A, Olivella S, Lloret A, Josa A. Physical and 3D numerical modelling of reinforcements pullout test. Sci Rep 2024; 14:7355. [PMID: 38548843 PMCID: PMC10978882 DOI: 10.1038/s41598-024-57893-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 03/22/2024] [Indexed: 04/01/2024] Open
Abstract
This paper reports results of laboratory and 3D numerical modeled pull-out tests with steel ladders and polymeric strip reinforcements. These types of reinforcement are commonly used in reinforced soil walls constructed with concrete facing elements. Laboratory pull-out tests are required to determine accurate and realistic pull-out strength values considering the interaction of specific reinforcement and backfill materials under different confining pressures (i.e., trying to simulate the different reinforcement layer arrangements and load conditions in actual reinforced soil walls). International design Codes for reinforced soil walls provide default values for pull-out strength. However, in many cases, default values are too conservative and/or are not strictly specified for particular reinforcement types. Pull-out tests can be difficult and expensive to perform, thus not being common nor worth for the vast majority of reinforced soil wall projects. Consequently, calibrated numerical models can be useful to predict pull-out response under site-specific conditions, and provide further understanding of the mechanisms involved in the soil-reinforcement interaction. Details of the numerical approach, including relevant aspects of the soil-reinforcement interfaces, are described. Examples of calibrated numerical predictions for pull-out loads, displacements, and soil-dilatancy effects are presented. The influence of reinforcement, soil and interface stiffnesses is shown. Numerical results provide useful insight for future modelling works of the complex interaction between type-specific backfill materials and reinforcement element, relevant for investigation and/or practical design of reinforced soil walls.
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Affiliation(s)
- Ivan P Damians
- Department of Civil and Environmental Engineering (DECA), Universitat Politècnica de Catalunya·BarcelonaTech (UPC), Barcelona, Spain.
- International Centre for Numerical Methods in Engineering (CIMNE), Barcelona, Spain.
- VSL International Ltd, Barcelona, Spain.
| | - Aníbal Moncada
- Department of Civil and Environmental Engineering (DECA), Universitat Politècnica de Catalunya·BarcelonaTech (UPC), Barcelona, Spain
- International Centre for Numerical Methods in Engineering (CIMNE), Barcelona, Spain
| | - Sebastià Olivella
- Department of Civil and Environmental Engineering (DECA), Universitat Politècnica de Catalunya·BarcelonaTech (UPC), Barcelona, Spain
- International Centre for Numerical Methods in Engineering (CIMNE), Barcelona, Spain
| | - Antonio Lloret
- Department of Civil and Environmental Engineering (DECA), Universitat Politècnica de Catalunya·BarcelonaTech (UPC), Barcelona, Spain
| | - Alejandro Josa
- Department of Civil and Environmental Engineering (DECA), Universitat Politècnica de Catalunya·BarcelonaTech (UPC), Barcelona, Spain
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Ye L, Wang K, Grasa J, Pierscionek BK. The Effect of Lens Shape, Zonular Insertion and Finite Element Model on Simulated Shape Change of the Eye Lens. Ann Biomed Eng 2024:10.1007/s10439-024-03491-3. [PMID: 38503945 DOI: 10.1007/s10439-024-03491-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/11/2024] [Indexed: 03/21/2024]
Abstract
The process of lens shape change in the eye to alter focussing (accommodation) is still not fully understood. Modelling approaches have been used to complement experimental findings in order to determine how constituents in the accommodative process influence the shape change of the lens. An unexplored factor in modelling is the role of the modelling software on the results of simulated shape change. Finite element models were constructed in both Abaqus and Ansys software using biological parameters from measurements of shape and refractive index of two 35-year-old lenses. The effect of zonular insertion on simulated shape change was tested on both 35-year-old lens models and with both types of software. Comparative analysis of shape change, optical power, and stress distributions showed that lens shape and zonular insertion positions affect the results of simulated shape change and that Abaqus and Ansys show differences in their respective models. The effect of the software package used needs to be taken into account when constructing finite element models and deriving conclusions.
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Affiliation(s)
- Lin Ye
- Faculty of Health Education Medicine and Social Care, Medical Technology Research Centre, Anglia Ruskin University, Chelmsford Campus, Chelmsford, UK
| | - Kehao Wang
- Beijing Advanced Innovation Centre for Biomedical Engineering, Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Engineering Medicine, Beihang University, Beijing, China
| | - Jorge Grasa
- Aragon Institute of Engineering Research (i3A), University of Zaragoza, Zaragoza, Spain
- Bioengineering, Biomaterials and Nanomedicine Networking Biomedical Research Centre (CIBER-BBN), Zaragoza, Spain
| | - Barbara K Pierscionek
- Faculty of Health Education Medicine and Social Care, Medical Technology Research Centre, Anglia Ruskin University, Chelmsford Campus, Chelmsford, UK.
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Minku, Ghosh R. A macro-micro FE and ANN framework to assess site-specific bone ingrowth around the porous beaded-coated implant: an example with BOX® tibial implant for total ankle replacement. Med Biol Eng Comput 2024:10.1007/s11517-024-03034-x. [PMID: 38321323 DOI: 10.1007/s11517-024-03034-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Accepted: 01/22/2024] [Indexed: 02/08/2024]
Abstract
The use of mechanoregulatory schemes based on finite element (FE) analysis for the evaluation of bone ingrowth around porous surfaces is a viable approach but requires significant computational time and effort. The aim of this study is to develop a combined macro-micro FE and artificial neural network (ANN) framework for rapid and accurate prediction of the site-specific bone ingrowth around the porous beaded-coated tibial implant for total ankle replacement (TAR). A macroscale FE model of the implanted tibia was developed based on CT data. Subsequently, a microscale FE model of the implant-bone interface was created for performing bone ingrowth simulations using mechanoregulatory algorithms. An ANN was trained for rapid and accurate prediction of bone ingrowth. The results predicted by ANN are well comparable to FE-predicted results. Predicted site-specific bone ingrowth using ANN around the implant ranges from 43.04 to 98.24%, with a mean bone ingrowth of around 74.24%. Results suggested that the central region exhibited the highest bone ingrowth, which is also well corroborated with the recent explanted study on BOX®. The proposed methodology has the potential to simulate bone ingrowth rapidly and effectively at any given site over any implant surface.
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Affiliation(s)
- Minku
- Biomechanics Research Laboratory, School of Mechanical & Materials Engineering, Indian Institute of Technology Mandi, Kamand, Mandi, 175075, Himachal Pradesh, India
| | - Rajesh Ghosh
- Biomechanics Research Laboratory, School of Mechanical & Materials Engineering, Indian Institute of Technology Mandi, Kamand, Mandi, 175075, Himachal Pradesh, India.
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Pupulin F, Oresta G, Sunar T, Parenti P. On the thermal impact during drilling operations in guided dental surgery: An experimental and numerical investigation. J Mech Behav Biomed Mater 2024; 150:106327. [PMID: 38104487 DOI: 10.1016/j.jmbbm.2023.106327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/10/2023] [Accepted: 12/11/2023] [Indexed: 12/19/2023]
Abstract
In recent years, a major development in dental implantology has been the introduction of patient-specific 3D-printed surgical guides. The utilization of dental guides offers advantages such as enhanced accuracy in locating the implant sites, greater simplicity, and reliability in performing bone drilling operations. However, it is important to note that the presence of such guides may contribute to a rise in cutting temperature, hence increasing the potential hazards of thermal injury to the patient's bone. The aim of this study is to examine the drilling temperature evolution in two distinct methods for 3D-printed surgical dental guides, one utilizing an internal metal bushing system and the other using external metal reducers. Cutting tests are done on synthetic polyurethane bone jaw models using a lab-scale automated Computer Numeric Control (CNC) machine to find out the temperature reached by different drilling techniques and compare them to traditional free cutting configurations. Thermal imaging and thermocouples, as well as the development of numerical simulations using finite element modeling, are used for the aim. The temperature of the tools' shanks experienced an average rise of 2.4 °C and 4.8 °C, but the tooltips exhibited an average increase of around 17 °C and 24 °C during traditional and guided dental surgery, respectively. This finding provides confirmation that both guided technologies have the capability to maintain temperatures below the critical limit for potential harm to bone and tissue. Numerical models were employed to validate and corroborate the findings, which exhibited identical outcomes when applied to genuine bone samples with distinct thermal characteristics.
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Affiliation(s)
- Francesca Pupulin
- Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20156, Milan, Italy
| | - Giorgio Oresta
- Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20156, Milan, Italy
| | - Talha Sunar
- Department of Manufacturing Engineering, Karabuk University, 78050, Karabük, Turkey
| | - Paolo Parenti
- Department of Mechanical Engineering, Politecnico di Milano, via La Masa 1, 20156, Milan, Italy.
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Glenday JD, Vigdorchik JM, Sculco PK, Kahlenberg CA, Mayman DJ, Debbi EM, Lipman JD, Wright TM, González FJQ. A novel computational workflow to holistically assess total knee arthroplasty biomechanics identifies subject-specific effects of joint mechanics on implant fixation. J Biomech 2024; 164:111973. [PMID: 38325192 DOI: 10.1016/j.jbiomech.2024.111973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 12/04/2023] [Accepted: 01/29/2024] [Indexed: 02/09/2024]
Abstract
Computational studies of total knee arthroplasty (TKA) often focus on either joint mechanics (kinematics and forces) or implant fixation mechanics. However, such disconnect between joint and fixation mechanics hinders our understanding of overall TKA biomechanical function by preventing identification of key relationships between these two levels of TKA mechanics. We developed a computational workflow to holistically assess TKA biomechanics by integrating musculoskeletal and finite element (FE) models. For our initial study using the workflow, we investigated how tibiofemoral contact mechanics affected the risk of failure due to debonding at the implant-cement interface using the four available subjects from the Grand Challenge Competitions to Predict In Vivo Knee Loads. We used a musculoskeletal model with a 12 degrees-of-freedom knee joint to simulate the stance phase of gait for each subject. The computed tibiofemoral joint forces at each node in contact were direct inputs to FE simulations of the same subjects. We found that the peak risk of failure did not coincide with the peak joint forces or the extreme tibiofemoral contact positions. Moreover, despite the consistency of joint forces across subjects, we observed important variability in the profile of the risk of failure during gait. Thus, by a combined evaluation of the joint and implant fixation mechanics of TKA, we could identify subject-specific effects of joint kinematics and forces on implant fixation that would otherwise have gone unnoticed. We intend to apply our workflow to evaluate the impact of implant alignment and design on TKA biomechanics.
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Affiliation(s)
- Jonathan D Glenday
- Hospital for Special Surgery, 535 East 71st Street, New York 10021, NY, USA
| | | | - Peter K Sculco
- Hospital for Special Surgery, 535 East 71st Street, New York 10021, NY, USA
| | | | - David J Mayman
- Hospital for Special Surgery, 535 East 71st Street, New York 10021, NY, USA
| | - Eytan M Debbi
- Hospital for Special Surgery, 535 East 71st Street, New York 10021, NY, USA
| | - Joseph D Lipman
- Hospital for Special Surgery, 535 East 71st Street, New York 10021, NY, USA
| | - Timothy M Wright
- Hospital for Special Surgery, 535 East 71st Street, New York 10021, NY, USA
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Garate Andikoetxea B, Ajami S, Rodriguez-Florez N, Jeelani NUO, Dunaway D, Schievano S, Borghi A. Towards a radiation free numerical modelling framework to predict spring assisted correction of scaphocephaly. Comput Methods Biomech Biomed Engin 2023:1-10. [PMID: 38108140 DOI: 10.1080/10255842.2023.2294262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Accepted: 12/08/2023] [Indexed: 12/19/2023]
Abstract
Sagittal Craniosynostosis (SC) is a congenital craniofacial malformation, involving premature sagittal suture ossification; spring-assisted cranioplasty (SAC) - insertion of metallic distractors for skull reshaping - is an established method for treating SC. Surgical outcomes are predictable using numerical modelling, however published methods rely on computed tomography (CT) scans availability, which are not routinely performed. We investigated a simplified method, based on radiation-free 3D stereophotogrammetry scans.Eight SAC patients (age 5.1 ± 0.4 months) with preoperative CT and 3D stereophotogrammetry scans were included. Information on osteotomies, spring model and post-operative spring opening were recorded. For each patient, two preoperative models (PREOP) were created: i) CT model and ii) S model, created by processing patient specific 3D surface scans using population averaged skin and skull thickness and suture locations. Each model was imported into ANSYS Mechanical (Analysis System Inc., Canonsburg, PA) to simulate spring expansion. Spring expansion and cranial index (CI - skull width over length) at times equivalent to immediate postop (POSTOP) and follow up (FU) were extracted and compared with in-vivo measurements.Overall expansion patterns were very similar for the 2 models at both POSTOP and FU. Both models had comparable outcomes when predicting spring expansion. Spring induced CI increase was similar, with a difference of 1.2%±0.8% for POSTOP and 1.6%±0.6% for FU.This work shows that a simplified model created from the head surface shape yields acceptable results in terms of spring expansion prediction. Further modelling refinements will allow the use of this predictive tool during preoperative planning.
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Affiliation(s)
| | - Sara Ajami
- University College London, United Kingdom
- Great Ormond Street Hospital, London, United Kingdom
| | | | | | - David Dunaway
- Great Ormond Street Hospital, London, United Kingdom
| | - Silvia Schievano
- University College London, United Kingdom
- Great Ormond Street Hospital, London, United Kingdom
| | - Alessandro Borghi
- University College London, United Kingdom
- Great Ormond Street Hospital, London, United Kingdom
- Department of Engineering, Durham University, Durham, United Kingdom
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14
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Nitish Prasad K, Ramkumar P. FEM wear prediction of ceramic hip replacement bearings under dynamic edge loading conditions. J Mech Behav Biomed Mater 2023; 146:106049. [PMID: 37531772 DOI: 10.1016/j.jmbbm.2023.106049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/26/2023] [Accepted: 07/27/2023] [Indexed: 08/04/2023]
Abstract
Hard-on-Hard hip implants, specifically ceramic tribo-pair, have produced the highest in-vivo wear resistance, biocompatibility, superior corrosion resistance, and high fracture toughness. However, this ceramic tribo-pair suffers from edge loading, sharply increasing wear and accelerating early implant failures due to micro-separation. Even though in-vitro studies have tested the occurrence of wear due to dynamic edge loading, the Finite Element Method (FEM) gives the advantage of accurately estimating the wear, minimizing the experimental time and cost. A new fundamental FEM model is developed to predict wear for ceramic hip replacement bearings under dynamic edge loading conditions for a fixed separation and fixed inclination angle. The model is directly validated with the existing hip simulator data up to 3 million cycles in terms of wear depth, wear scar and volumetric wear rate. The results from the model show that the accuracy in wear prediction was more than 98% for the wear depth and volumetric wear rate for the dynamic edge loading condition. A stripe wear scar is captured, depicting the edge loading conditions. The developed model from this study can predict wear under pure standard and dynamic edge loading conditions.
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Affiliation(s)
- K Nitish Prasad
- Advanced Tribology Research Lab (ATRL), Machine Design Section, Department of Mechanical Engineering, Indian Institute of Technology Madras (IITM), Chennai, India
| | - P Ramkumar
- Advanced Tribology Research Lab (ATRL), Machine Design Section, Department of Mechanical Engineering, Indian Institute of Technology Madras (IITM), Chennai, India.
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15
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Guo L, Boakye E, Sadleir RJ, Holdefer RN. Transcranial MEP threshold voltages and current densities simulated with finite element modelling. Clin Neurophysiol 2023; 154:1-11. [PMID: 37524004 DOI: 10.1016/j.clinph.2023.06.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2022] [Revised: 05/30/2023] [Accepted: 06/21/2023] [Indexed: 08/02/2023]
Abstract
OBJECTIVE The aim of this study was to compare stimulation thresholds and current densities in the brain for transcranial motor evoked potentials (tcMEPs) from the hands and feet with linked quadripolar (LQP), M3-M4 and C1-C2 electrode montages. METHODS Twenty-five patients underwent cerebral vascular surgery with tcMEP monitoring. tcMEP voltage thresholds were compared between LQP (C1, M3, C2, M4), C1-C2, and M3-M4 montages. In a finite element model (FEM), hand, arm, and leg regions of interest (ROIs) on the cortical motor homunculus were segmented. Current densities in these ROIs at tcMEP thresholds were compared across tcMEP electrode montages. RESULTS LQP tcMEP thresholds were 61.5 volts for hands and 95.2 volts for feet. Thresholds were higher for M3-M4 (hands, 89.4 V; feet, 141.3 V) and C1-C2 (hands: 137.3 V; feet: 194.7 V). Total current at threshold voltage was greater for LQP (hands, 210.9 mA; feet, 311.3 mA) compared to M3-M4 (hands, 166.8 mA; feet, 256.6 mA), but similar to C1-C2 (hands, 246.7 mA; feet, 341.1 mA). In FEM simulations, current density and local current density topography in the hand ROI at threshold were very similar for LQP, M3-M4 and C1-C2. CONCLUSIONS TcMEP voltage thresholds were least for LQP, and lesser for M3-M4 compared to C1-C2. In FEM simulations, resistance to current to hand ROI was ordered the same (LQP < M3-M4 < C1-C2). The local distribution of current density in motor cortex with tcMEP was mainly determined by cortical geometry. SIGNIFICANCE Current densities and resistance to current simulated with FEM may explain threshold requirements for tcMEP electrode montages.
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Affiliation(s)
- Lanjun Guo
- Department of Surgical Neurophysiology, University of California - San Francisco, San Francisco, CA, USA
| | - Enock Boakye
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
| | - Rosalind J Sadleir
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, USA
| | - Robert N Holdefer
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA, USA.
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Hitchon S, Anderson W, Milner JS, Hong G, Ivanov T, Willing R, Holdsworth D. Static compression and fatigue behavior of heat-treated selective laser melted titanium alloy (Ti6Al4V) gyroid cylinders. J Mech Behav Biomed Mater 2023; 146:106076. [PMID: 37598509 DOI: 10.1016/j.jmbbm.2023.106076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/31/2023] [Accepted: 08/13/2023] [Indexed: 08/22/2023]
Abstract
Porous additively-manufactured structures could have a niche in orthopaedic implants, due to their potential to reduce stiffness (stress-shielding), improve bony ingrowth, and potential to house reservoirs of drug-eluting non-structural biomaterials. Computer aided design and finite element (FE) modelling plays an important role in the design of porous structured biomedical implants; however it is important to validate both their static and fatigue behaviours using experimental testing. This study compared the mechanical behaviors of titanium cylindrical gyroid structures of varying porosities using physical testing of additively manufactured prototypes and FE models. There was agreement in the measured and predicted relationships between porosity and apparent modulus of elasticity. As porosity increased (and wall thickness decreased), the structures failed at a lower number of cycles when loaded at the same percentage of their yield strengths. Calibration of the fatigue strength coefficient from a previously published value of 1586.5 MPa-1225 MPa greatly improved the fatigue life prediction accuracy for all the gyroid structures. Nevertheless, differences of up to 54% in the predicted versus experimental fatigue lives remained, which could be attributed to difficulties with how the precise time and location of failure is defined in the simulations, and/or minor differences in nominal and actual porosities. Although further calibration and validation should be explored, this study demonstrates that static and fatigue FE-modelling techniques could be used to aid in the design of porous prosthetics.
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Affiliation(s)
- Sydney Hitchon
- School of Biomedical Engineering, Western University, London, Ontario, Canada; Bone and Joint Institute, Western University, London, Ontario, Canada
| | - William Anderson
- School of Biomedical Engineering, Western University, London, Ontario, Canada; Bone and Joint Institute, Western University, London, Ontario, Canada
| | - Jaques S Milner
- Robarts Research Institute, Western University, London, Ontario, Canada
| | - Gregory Hong
- Bone and Joint Institute, Western University, London, Ontario, Canada; Robarts Research Institute, Western University, London, Ontario, Canada; Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Todor Ivanov
- Robarts Research Institute, Western University, London, Ontario, Canada
| | - Ryan Willing
- School of Biomedical Engineering, Western University, London, Ontario, Canada; Bone and Joint Institute, Western University, London, Ontario, Canada; Department of Mechanical and Materials Engineering, Western University, London, Ontario, Canada.
| | - David Holdsworth
- Bone and Joint Institute, Western University, London, Ontario, Canada; Robarts Research Institute, Western University, London, Ontario, Canada; Department of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
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17
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Wang X, Liu H, Dong Z, Chen X, Xu C, Ji G, Kang H, Wang F. Contact area and pressure changes of patellofemoral joint during stair ascent and stair descent. BMC Musculoskelet Disord 2023; 24:767. [PMID: 37770867 PMCID: PMC10537124 DOI: 10.1186/s12891-023-06882-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 09/13/2023] [Indexed: 09/30/2023] Open
Abstract
PURPOSE To investigate the differences of patellofemoral joint pressure and contact area between the process of stair ascent and stair descent. METHODS The finite element models of 9 volunteers without disorders of knee (9 males) to estimate patellar cartilage pressure during the stair ascent and the stair descent. Simulations took into account cartilage morphology from magnetic resonance imaging, joint posture from weight-bearing magnetic resonance imaging, and ligament model. The three-dimension models of the patella, femur and tibia were developed with the medical image processing software, Mimics 11.1. The ligament was established by truss element of the non-linear FE solver. The equivalent gravity direction (-z direction) load was applied to the whole end of femur (femoral head) according to the body weight of the volunteers, and the force of patella was observed. A paired-samples t-test or Wilcoxon rank sum test to make comparisons between stair ascent and stair descent. Statistical analyses were performed using SPSS 22.0 using a P value of 0.05 to indicate significance. RESULTS During the stair descent (knee flexion at 30°), the contact pressure of the patella was 2.59 ± 0.06Mpa. The contact pressure of femoral trochlea cartilage was 2.57 ± 0.06Mpa. During the stair ascent (knee flexion at 60°), the contact pressure with patellar cartilage was 2.82 ± 0.08Mpa. The contact pressure of the femoral trochlea cartilage was 3.03 ± 0.11Mpa. The contact area between patellar cartilage and femoral trochlea cartilage was 249.27 ± 1.35mm2 during the stair descent, which was less than 434.32 ± 1.70mm2 during the stair ascent. The area of high pressure was located in the lateral area of patella during stair descent and the area of high pressure was scattered during stair ascent. CONCLUSION There are small change in the cartilage contact pressure between stair ascent and stair descent, indicating that the joint adjusts the contact pressure by increasing the contact area.
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Affiliation(s)
- Xiaomeng Wang
- Foot and Ankle Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Huixin Liu
- Ultrasound medicine department, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Zhenyue Dong
- Department of Joint Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Xiaobo Chen
- Department of Joint Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Chenyue Xu
- Department of Joint Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Gang Ji
- Department of Joint Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Huijun Kang
- Department of Joint Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China
| | - Fei Wang
- Department of Joint Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, China.
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18
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Lustig M, Epstein Y, Gefen A. An anatomically-realistic computational framework for evaluating the efficacy of protective plates in mitigating non-penetrating ballistic impacts. Comput Biol Med 2023; 166:107490. [PMID: 37738897 DOI: 10.1016/j.compbiomed.2023.107490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/03/2023] [Accepted: 09/15/2023] [Indexed: 09/24/2023]
Abstract
BACKGROUND A major threat in combat scenarios is the 'behind armor blunt trauma' (BABT) of a non-penetrating ballistic impact with a ballistic protective plate (BPP). This impact results in pressure waves that propagate through tissues, potentially causing life-threatening damage. To date, there is no standardized procedure for rapid virtual testing of the effectiveness of BPP designs. The objective of this study was to develop a novel, anatomically-accurate, finite element modeling framework, as a decision-making tool to evaluate and rate the biomechanical efficacy of BPPs in protecting the torso from battlefield-acquired non-penetrating impacts. METHODS To simulate a blunt impact with a BPP, two types of BPPs representing generic designs of threat-level III and IV plates, and a generic 5.56 mm bullet were modeled, based on their real dimensions, physical and mechanical characteristics (plate level-III is smaller, thinner, and lighter than plate level-IV). The model was validated by phantom testing. RESULTS Plate level-IV induced greater strains and stresses in the superficial tissues post the ballistic impact, due to the fact that it is larger, thicker and heavier than plate level-III; the shock wave which is transferred to the superficial tissues behind the BPP is greater in the case of a non-penetrating impact. For example - the area under volumetric tissue exposure histograms of strains and stresses for the skin and adipose tissues were 16.6-19.2% and 17.3-20.3% greater in the case of plate level-IV, for strains and stresses, respectively. The validation demonstrates a strong agreement between the physical phantom experiment and the simulation, with only a 6.37% difference between them. CONCLUSIONS Our modelling provides a versatile, powerful testing framework for both industry and clients of BPPs at the prototype design phase, or for quantitative standardized evaluations of candidate products in purchasing decisions and bids.
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Affiliation(s)
- Maayan Lustig
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yoram Epstein
- School of Public Health, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Amit Gefen
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel.
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19
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van Agtmaal JL, Doodkorte RJP, Roth AK, Ito K, Arts JJC, Willems PC, van Rietbergen B. Biomechanical evaluation of different semi-rigid junctional fixation techniques using finite element analysis. Clin Biomech (Bristol, Avon) 2023; 108:106071. [PMID: 37597385 DOI: 10.1016/j.clinbiomech.2023.106071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 08/09/2023] [Accepted: 08/11/2023] [Indexed: 08/21/2023]
Abstract
BACKGROUND Proximal junctional failure is a common complication attributed to the rigidity of long pedicle screw fixation constructs used for surgical correction of adult spinal deformity. Semi-rigid junctional fixation achieves a gradual transition in range of motion at the ends of spinal instrumentation, which could lead to reduced junctional stresses, and ultimately reduce the incidence of proximal junctional failure. This study investigates the biomechanical effect of different semi-rigid junctional fixation techniques in a T8-L3 finite element spine segment model. METHODS First, degeneration of the intervertebral disc was successfully implemented by altering the height. Second, transverse process hooks, one- and two-level clamped tapes, and one- and two-level knotted tapes instrumented proximally to three-level pedicle screw fixation were validated against ex vivo range of motion data of a previous study. Finally, the posterior ligament complex forces and nucleus pulposus stresses were quantified. FINDINGS Simulated range of motions demonstrated the fidelity of the general model and modelling of semi-rigid junctional fixation techniques. All semi-rigid junctional fixation techniques reduced the posterior ligament complex forces at the junctional zone compared to pedicle screw fixation. Transverse process hooks and knotted tapes reduced nucleus pulposus stresses, whereas clamped tapes increased nucleus pulposus stresses at the junctional zone. INTERPRETATION The relationship between the range of motion transition and the reductions in posterior ligament complex and nucleus pulposus stresses was complex and dependent on the fixation techniques. Clinical trials are required to compare the effectiveness of semi-rigid junctional fixation techniques in terms of reducing proximal junctional failure incidence rates.
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Affiliation(s)
- Julia L van Agtmaal
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven, the Netherlands; Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands
| | - Remco J P Doodkorte
- Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands
| | - Alex K Roth
- Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands
| | - Keita Ito
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven, the Netherlands
| | - Jacobus J C Arts
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven, the Netherlands; Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands
| | - Paul C Willems
- Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands
| | - Bert van Rietbergen
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Den Dolech 2, 5612AZ Eindhoven, the Netherlands; Department of Orthopaedic Surgery, Research School CAPHRI, Maastricht University Medical Center, P. Debyelaan 25, 6229HX Maastricht, the Netherlands.
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20
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Zamani Zakaria A, Jepps OG, Gould T, Anissimov YG. Permeable Cornified Envelope Layer Regulates the Solute Transport in Human Stratum Corneum. J Pharm Sci 2023; 112:1939-1946. [PMID: 36931344 DOI: 10.1016/j.xphs.2023.03.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 03/06/2023] [Accepted: 03/06/2023] [Indexed: 03/17/2023]
Abstract
To unravel the diffusion mechanisms of percutaneous drug delivery, suitable numerical analysis of stratum corneum structure is essential. In this research paper, we accounted for the permeable envelope layer in the brick-and-mortar finite element models of human stratum corneum. Both penetration and desorption experiments for tritiated water were simulated by transient finite element analysis. Rivet-shaped corneodesmosomes were included in the brick and mortar model. Results showed that cornified lipid permeability (Penv) is a determinant in desorption of the solute, while lipid transverse diffusion coefficient (Dlip-trans) is prominent during penetration. These two major unknowns (Penv and Dlip-trans) were obtained by extensive fitting of the finite element model to the experimental water data. Penv and Dlip-trans were determined to be 1×10-2 cm/s and 5.7×10-10 cm2/s, respectively.
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Affiliation(s)
- Afshin Zamani Zakaria
- School of Environment and Science, Griffith University, Queensland 4111, Australia; Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland 4111, Australia.
| | - Owen G Jepps
- School of Environment and Science, Griffith University, Queensland 4111, Australia; Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland 4111, Australia.
| | - Tim Gould
- School of Environment and Science, Griffith University, Queensland 4111, Australia; Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland 4111, Australia
| | - Yuri G Anissimov
- Queensland Micro and Nanotechnology Centre, Griffith University, Nathan, Queensland 4111, Australia
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21
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Valerio T, Vigouroux L, Goislard de Monsabert B, De Villeneuve Bargemon JB, Milan JL. Relationship between trapeziometacarpal joint morphological parameters and joint contact pressure: a possible factor of osteoarthritis development. J Biomech 2023; 152:111573. [PMID: 37037117 DOI: 10.1016/j.jbiomech.2023.111573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 03/10/2023] [Accepted: 03/27/2023] [Indexed: 04/08/2023]
Abstract
The trapeziometacarpal (TMC) joint is the one of the hand joints that is most affected by osteoarthritis (OA). The objective of this study was to determine if specific morphological parameters could be related to the amount of pressure endured by the joint which is one of the factors contributing to the development of this pathology. We developed 15 individualized 3D computer aided design (CAD) models of the TMC joint, each generated from the CT scan of a different participant. For each participant, we measured several crucial morphological parameters: the width and length of the trapezium bone and dorso-volar and ulno-radial curvature, of the trapezium and the metacarpal bone. Each CAD model was converted into a finite element model, of both bones and the cartilage located in between. The joint forces applied during pinch grip and power grip tasks were then applied in order to estimate the contact pressures on joint cartilage for each model. Correlations between joint contact pressures and morphology of the trapezium and the metacarpal bone were then analysed. Important variations of TMC joint pressures were observed. For both pinch and power grip tasks, the strongest correlation with joint contact pressure was with the dorso-volar curvature of the trapezium bone. Our findings indicate that dorso-volar curvature of the trapezium bone has a significant impact on mechanical loadings on the TMC joint. This contributes to understanding the prevalence of OA in certain patients.
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Affiliation(s)
- Thomas Valerio
- Aix-Marseille University, CNRS, ISM, Marseille, France; Aix-Marseille University, APHM, CNRS, ISM, St Marguerite Hospital, Institute for Locomotion, Department of Orthopaedics and Traumatology, Marseille, France.
| | | | | | | | - Jean-Louis Milan
- Aix-Marseille University, CNRS, ISM, Marseille, France; Aix-Marseille University, APHM, CNRS, ISM, St Marguerite Hospital, Institute for Locomotion, Department of Orthopaedics and Traumatology, Marseille, France
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Tan ZQ, Ooi EH, Chiew YS, Foo JJ, Ng EYK, Ooi ET. A computational framework for the multiphysics simulation of microbubble-mediated sonothrombolysis using a forward-viewing intravascular transducer. Ultrasonics 2023; 131:106961. [PMID: 36812819 DOI: 10.1016/j.ultras.2023.106961] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/08/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Sonothrombolysis is a technique that utilises ultrasound waves to excite microbubbles surrounding a clot. Clot lysis is achieved through mechanical damage induced by acoustic cavitation and through local clot displacement induced by acoustic radiation force (ARF). Despite the potential of microbubble-mediated sonothrombolysis, the selection of the optimal ultrasound and microbubble parameters remains a challenge. Existing experimental studies are not able to provide a complete picture of how ultrasound and microbubble characteristics influence the outcome of sonothrombolysis. Likewise, computational studies have not been applied in detail in the context of sonothrombolysis. Hence, the effect of interaction between the bubble dynamics and acoustic propagation on the acoustic streaming and clot deformation remains unclear. In the present study, we report for the first time the computational framework that couples the bubble dynamic phenomena with the acoustic propagation in a bubbly medium to simulate microbubble-mediated sonothrombolysis using a forward-viewing transducer. The computational framework was used to investigate the effects of ultrasound properties (pressure and frequency) and microbubble characteristics (radius and concentration) on the outcome of sonothrombolysis. Four major findings were obtained from the simulation results: (i) ultrasound pressure plays the most dominant role over all the other parameters in affecting the bubble dynamics, acoustic attenuation, ARF, acoustic streaming, and clot displacement, (ii) smaller microbubbles could contribute to a more violent oscillation and improve the ARF simultaneously when they are stimulated at higher ultrasound pressure, (iii) higher microbubbles concentration increases the ARF, and (iv) the effect of ultrasound frequency on acoustic attenuation is dependent on the ultrasound pressure. These results may provide fundamental insight that is crucial in bringing sonothrombolysis closer to clinical implementation.
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Affiliation(s)
- Zhi Q Tan
- Mechanical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia
| | - Ean H Ooi
- Mechanical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia; Advanced Engineering Platform, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia.
| | - Yeong S Chiew
- Mechanical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia
| | - Ji J Foo
- Mechanical Engineering Discipline, School of Engineering, Monash University Malaysia, Jalan Lagoon Selatan, 47500 Bandar Sunway, Selangor, Malaysia
| | - Eddie Y K Ng
- School of Mechanical and Aerospace Engineering, College of Engineering, Nanyang Technological University, 50 Nanyang Avenue 639798, Singapore
| | - Ean T Ooi
- School of Engineering and Information Technology, Faculty of Science and Technology, Federation University, VIC 3350, Australia
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23
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Thompson CW, Rohani SA, Dirckx JJ, Ladak HM, Agrawal SK. Finite element modelling of the human middle ear using synchrotron-radiation phase-contrast imaging. Comput Biol Med 2023; 157:106747. [PMID: 36907036 DOI: 10.1016/j.compbiomed.2023.106747] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Revised: 02/18/2023] [Accepted: 03/04/2023] [Indexed: 03/08/2023]
Abstract
Finite element (FE) models of the middle ear often lack accurate geometry of soft tissue structures, such as the suspensory ligaments, as they can be difficult to discern using conventional imaging modalities, such as computed tomography. Synchrotron-radiation phase-contrast imaging (SR-PCI) is a non-destructive imaging modality that has been shown to produce excellent visualization of soft tissue structures without the need for extensive sample preparation. The objectives of the investigation were to firstly use SR-PCI to create and evaluate a biomechanical FE model of the human middle ear that includes all soft tissue structures, and secondly, to investigate how modelling assumptions and simplifications of ligament representations affect the simulated biomechanical response of the FE model. The FE model included the suspensory ligaments, ossicular chain, tympanic membrane, the incudostapedial and incudomalleal joints, and the ear canal. Frequency responses obtained from the SR-PCI-based FE model agreed well with published laser doppler vibrometer measurements on cadaveric samples. Revised models with exclusion of the superior malleal ligament (SML), simplification of the SML, and modification of the stapedial annular ligament were studied, as these revised models represented modelling assumptions that have been made in literature.
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Affiliation(s)
- Caleb W Thompson
- Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada.
| | - Seyed A Rohani
- Department of Otolaryngology - Head and Neck Surgery, Western University, London, Ontario, Canada
| | - Joris J Dirckx
- Laboratory of Biomedical Physics, University of Antwerp, Antwerp, Belgium
| | - Hanif M Ladak
- Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada; Department of Medical Biophysics, Western University, London, Ontario, Canada; Department of Otolaryngology - Head and Neck Surgery, Western University, London, Ontario, Canada
| | - Sumit K Agrawal
- Department of Otolaryngology - Head and Neck Surgery, Western University, London, Ontario, Canada
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O'Rourke D, Johnson LJ, Jagiello J, Taylor M. Examining agreement between finite element modelling methodologies in predicting pathological fracture risk in proximal femurs with bone metastases. Clin Biomech (Bristol, Avon) 2023; 104:105931. [PMID: 36906986 DOI: 10.1016/j.clinbiomech.2023.105931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 02/09/2023] [Accepted: 03/03/2023] [Indexed: 03/14/2023]
Abstract
BACKGROUND Finite element modelling methodologies available for assessing femurs with metastases accurately predict strength and pathological fracture risk which has led them to being considered for implementation into the clinic. However, the models available use varying material models, loading conditions, and critical thresholds. The aim of this study was to determine the agreement between finite element modelling methodologies in assessing fracture risk in proximal femurs with metastases. METHODS CT images of the proximal femur were obtained of 7 patients who presented with a pathologic femoral fracture (fracture group) and the contralateral femur of 11 patients scheduled for prophylactic surgery (non-fracture group). Fracture risk was predicted for each patient following three established finite modelling methodologies which have previously shown to accurately predict strength and determine fracture risk: non-linear isotropic -based model, strain fold ratio -based model, Hoffman failure criteria -based model. FINDINGS The methodologies demonstrated good diagnostic accuracy in assessing fracture risk (AUC = 0.77, 0.73, and 0.67). There was a stronger monotonic association between the non-linear isotropic and Hoffman -based models (τ = 0.74) than with the strain fold ratio model (τ = -0.24 and - 0.37). There was moderate or low agreement between methodologies in discriminating between individuals at high or low risk of fracture (κ = 0.20, 0.39, and 0.62). INTERPRETATION The present results suggest there may be a lack of consistency in the management of pathological fractures in the proximal femur based on the finite element modelling methodologies.
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Affiliation(s)
- Dermot O'Rourke
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology, Brisbane, Australia; Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, Australia.
| | - Luke J Johnson
- South Australian Bone & Soft Tissue Tumour Unit, Flinders Medical Centre, Adelaide, Australia; College of Medicine and Public Health, Flinders University, Adelaide, Australia
| | - Jakub Jagiello
- South Australian Bone & Soft Tissue Tumour Unit, Flinders Medical Centre, Adelaide, Australia; Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia
| | - Mark Taylor
- Medical Device Research Institute, College of Science and Engineering, Flinders University, Adelaide, Australia
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Atthapreyangkul A, Hoffman M, Pearce G, Standard O. Effect of geometrical structure variations on strength and damage onset of cortical bone using multi-scale cohesive zone based finite element method. J Mech Behav Biomed Mater 2023; 138:105578. [PMID: 36427415 DOI: 10.1016/j.jmbbm.2022.105578] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022]
Abstract
Three-dimensional multi-scale finite element models were designed to examine the effects of geometrical structure variations on the damage onset in cortical bone at multiple structural scales. A cohesive zone finite element approach, together with anisotropic damage initiation criteria, is used to predict the onset of damage. The finite element models are developed to account for the onset of microdamage from the microscopic length scales consisting of collagen fibres, to the macroscopic level consisting of osteons and the Haversian canals. Numerical results indicated that the yield strain at the initiation of microcracks is independent of variations in the local mineral volume fraction at each structural scale. Further, the yield strain and strength properties of cortical bone are dependent on its structural anisotropy and hierarchical structure. A positive correlation is observed between bone strength and mineral content at each length scale.
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Affiliation(s)
| | - Mark Hoffman
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia; School of Engineering, The University of Newcastle, NSW, 2308, Australia.
| | - Garth Pearce
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney, NSW, 2052, Australia
| | - Owen Standard
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia
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Jebalia I, Della Valle G, Guessasma S, Kristiawan M. Cell walls of extruded pea snacks: Morphological and mechanical characterisation and finite element modelling. Food Res Int 2022; 162:112047. [PMID: 36461312 DOI: 10.1016/j.foodres.2022.112047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/03/2022] [Accepted: 10/12/2022] [Indexed: 11/04/2022]
Abstract
Pulses extruded foods can be envisaged asall solid foams with voids and walls, the latter being considered as a dense starch/protein composite. Pea flour (PF) and blends of pea starch and pea protein isolate (PPI) with different protein contents (0.5-88% dry basis) were extruded to obtain models of dense starch-protein composites. Their morphology was revealed by CLSM microscopy, and their mechanical properties were investigated using a three-point bending test complemented by Finite Element Method (FEM) modelling. Composite morphology revealed protein aggregates dispersed in the starch matrix. It was described by a starch-protein interface index Ii computed from the measured total area and perimeter of protein aggregates. The mechanical test showed that the extruded PF and PPI ruptured in the elastic domain, while the extruded starch-PPI (SP) blends ruptured in the plasticity domain. The mechanical properties of pea composites were weakened by increasing the particle volume fractions, including proteins and fibres, probably due to the poor adhesion between starch and the other constituents. The mechanical behaviour of pea composites did not accurately follow simple mixing laws because of their morphological heterogeneity. Modelling results show that the elastoplastic constitutive model using the Voce plasticity model satisfactorily described the hardening behaviour of SP blend composites. Reasonable agreement (2-10%) was found between the experimental and modelling approaches for most materials. The computed Young's modulus (1.3-2.5 GPa) and saturation flow stress (20-45 MPa) increased with increasing Ii (0.7-3.1), reflecting the increase of interfacial stiffening with the increase of contact area between starch and proteins. FEM modelling allowed to identify the mechanical effect of structural heterogeneities.
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Affiliation(s)
- I Jebalia
- INRAE, UR 1268 Biopolymers Interactions and Assemblies (BIA), 44316 Nantes, France.
| | - G Della Valle
- INRAE, UR 1268 Biopolymers Interactions and Assemblies (BIA), 44316 Nantes, France.
| | - S Guessasma
- INRAE, UR 1268 Biopolymers Interactions and Assemblies (BIA), 44316 Nantes, France.
| | - M Kristiawan
- INRAE, UR 1268 Biopolymers Interactions and Assemblies (BIA), 44316 Nantes, France
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Sciegaj A, Wojtczak E, Rucka M. The effect of external load on ultrasonic wave attenuation in steel bars under bending stresses. Ultrasonics 2022; 124:106748. [PMID: 35405600 DOI: 10.1016/j.ultras.2022.106748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 01/21/2022] [Accepted: 04/03/2022] [Indexed: 06/14/2023]
Abstract
The stress state in deformed solids has a significant impact on the attenuation of an ultrasonic wave propagating through the medium. Measuring a signal with certain attenuation characteristics can therefore provide useful diagnostic information about the stress state in the structure. In this work, basic principles behind a novel attenuation-based diagnostic framework are introduced. An experimental study on steel bars under three-point bending was carried out, and finite element analyses were used to numerically model the experiments. Obtained test results showed a strong correlation between the external load and the ultrasonic signal energy, which decreases with increasing load. A similar but positive correlation appeared between the level of attenuation of longitudinal ultrasonic wave signals and the external load, which allowed for efficient estimation of the mid-span bending moment. Upon proper calibration of testing equipment, the change in ultrasonic signal energy can therefore be used as an indicator of the external load level. As a result, this effect has potential applications in non-destructive structural health monitoring frameworks.
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Affiliation(s)
- Adam Sciegaj
- Department of Mechanics of Materials and Structures, Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
| | - Erwin Wojtczak
- Department of Mechanics of Materials and Structures, Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
| | - Magdalena Rucka
- Department of Mechanics of Materials and Structures, Faculty of Civil and Environmental Engineering, Gdańsk University of Technology, Narutowicza 11/12, 80-233 Gdańsk, Poland.
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El Bojairami I, Jacobson N, Driscoll M. Development and evaluation of a numerical spine model comprising intra-abdominal pressure for use in assessing physiological changes on abdominal compliance and spinal stability. Clin Biomech (Bristol, Avon) 2022; 97:105689. [PMID: 35717701 DOI: 10.1016/j.clinbiomech.2022.105689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 05/24/2022] [Accepted: 05/31/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Abdominal compliance is the "measure of ease of abdominal expansion" and determines whether a patient can withstand high intra-abdominal pressures. Thus, high compliance indicates that the abdomen can expand relatively freely, while low compliance restricts abdominal expansion. The global objective of the present work is to evaluate the effect of physiological changes on abdominal compliance using a comprehensive spine finite element model inclusive of intra-abdominal pressure. METHODS The effect of changing Young's modulus, abdominal wall thickness, and abdominal radii on abdominal compliance were evaluated. Intra-abdominal pressure and thoracolumbar fascia forces were also evaluated to assess abdominal physiological changes effects on overall static spinal stability. FINDINGS Results showed that as wall thickness increased, compliance decreased. Similar findings were made with an increase in abdominal radius and Young's modulus. Furthermore, the active reduction in compliance, caused by increased elasticity and abdominal radius, resulted in an increase in spinal supportive forces originating from the thoracolumbar fascia and intra-abdominal pressurization, along with an increase in spine displacement from its original stable position. There was no clear stability trend for the case of changing abdominal wall thickness as fluctuations were present. INTERPRETATION Investigated mechanics and data trends suggested that dangerously low compliance levels might result from poor abdominal elasticity and thickening fat layers. This led to a direct discussion and recommendations for obesity conditions and laparoscopy applications. Lastly, static spinal stability showed to improve through increasing active abdominal compliance by means of actively engaging abdominal pressure, hence augmenting abdominal active elasticity.
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Affiliation(s)
- Ibrahim El Bojairami
- Musculoskeletal Biomechanics Research Lab, Department of Mechanical Engineering, McGill University, Montréal, Quebec, Canada; Orthopaedic Research Laboratory, Department of Surgery, McGill University, Montréal, Quebec, Canada.
| | - Natasha Jacobson
- Musculoskeletal Biomechanics Research Lab, Department of Mechanical Engineering, McGill University, Montréal, Quebec, Canada; Orthopaedic Research Laboratory, Department of Surgery, McGill University, Montréal, Quebec, Canada.
| | - Mark Driscoll
- Musculoskeletal Biomechanics Research Lab, Department of Mechanical Engineering, McGill University, Montréal, Quebec, Canada; Orthopaedic Research Laboratory, Department of Surgery, McGill University, Montréal, Quebec, Canada.
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El Bojairami I, Driscoll M. Formulation and exploration of novel, intramuscular pressure based, muscle activation strategies in a spine model. Comput Biol Med 2022; 146:105646. [PMID: 35751204 DOI: 10.1016/j.compbiomed.2022.105646] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 04/26/2022] [Accepted: 05/14/2022] [Indexed: 12/31/2022]
Abstract
Optimization models are often devised to assess spinal stability via estimating individual muscle forces. However, neglecting muscles' fluidic behavior remains an approximation due to the role of muscle pressure in force transmission. The purpose of this study was to leverage a validated Finite Element (FE) model of the spine, inclusive of Intra-Muscular Pressure (IMP), to explore muscle activation strategies towards maintaining equilibrium spinal stability. Three conventional strategies governing minimizing muscle effort, minimizing IVD compressive forces, and maintaining stability at all costs were first investigated to explore model's validity. Thereafter, two novel IMP-based strategies were devised and explored, specifically minimizing and maximizing IMP. The model was previously shown valid in light of in vivo and in silico observations with an average discrepancy of 6%. This being the case, the conventional strategies dictated efficacy in muscular activations whilst maintaining an equilibrium stable position, as quantified in the present paper, with a difference of 9.8% from documented data. In addition, the explored novel IMP-based strategies suggested the presence of a threshold individual muscles IMP, approximately 272 mmHg for the longissimus muscle for example, beyond which muscles potentially start to share radial loads with surrounding tissues, whilst limiting the contraction of the underlying muscles. In conclusion, this study theoretically supports the possibility of activation strategies based on muscular pressure, which the developed, verified, and validated FE spine model was leveraged to investigate. The explored novel IMP-based strategies may have significance in informing clinical applications such as motion analysis and functional electrical stimulation of muscles.
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Affiliation(s)
- Ibrahim El Bojairami
- Musculoskeletal Biomechanics Research Lab, Department of Mechanical Engineering, McGill University, Montréal, Quebec, Canada; Orthopaedic Research Lab, Montreal General Hospital, McGill University Hospital Center Research Institute, Montréal, Quebec, Canada.
| | - Mark Driscoll
- Musculoskeletal Biomechanics Research Lab, Department of Mechanical Engineering, McGill University, Montréal, Quebec, Canada; Orthopaedic Research Lab, Montreal General Hospital, McGill University Hospital Center Research Institute, Montréal, Quebec, Canada.
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Zhang G, Yang S, Cui W, Peng X, Zhang X, Zhang Y, Li J, Jin Z. Parametric analysis of the effect of impaction load on the stability of head-neck junction in total hip arthroplasty. Clin Biomech (Bristol, Avon) 2022; 94:105633. [PMID: 35364404 DOI: 10.1016/j.clinbiomech.2022.105633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 03/15/2022] [Accepted: 03/22/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Tribocorrosion at head-neck interface is one of the main causes leading to the failure of hip implants in total hip arthroplasty. Impaction load has been acknowledged as one of the key factors influencing the stability of the taper junction. It is understood that the magnitude of impaction force differs from the surgeon to surgeon in primary total hip arthroplasty or revision. Clinically, it is sufficient enough to keep the male and female tapers inseparable utilizing a low impaction, which seems to contradict previous researches. The objective of this study was to investigate the effect of impaction loads on the stability of taper junction during assembly and gaits. METHODS A finite element model with 12/14 taper and the taper mismatch of 4' was developed for investigation. The impaction force profiles were collected from surgeon as the inputs, and then the contact mechanics over one or multiple gaits was further analyzed and validated utilizing hip simulator test. FINDINGS Impaction force ranging from 200 to 2000 N could provide the same taper connection effect after the first gait due to the secondary seating. As for impaction loads of 3000 N and above, an increased impaction force would lead to the tighter taper connection. INTERPRETATION The effect of impaction load on the stability of head-neck junction is a piecewise function, indicating that the stability of taper junction is not affected by different impaction loads and tends to be consistent while its magnitude is below the threshold. Instead, the stability of taper junction is positively correlated with impaction force.
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Khaw JS, Xue R, Cassidy NJ, Cartmell SH. Electrical stimulation of titanium to promote stem cell orientation, elongation and osteogenesis. Acta Biomater 2022; 139:204-217. [PMID: 34390847 DOI: 10.1016/j.actbio.2021.08.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 07/06/2021] [Accepted: 08/06/2021] [Indexed: 11/29/2022]
Abstract
Electrical stimulation of cells allows exogenous electric signals as stimuli to manipulate cell growth, preferential orientation and bone remodelling. In this study, commercially pure titanium discs were utilised in combination with a custom-built bioreactor to investigate the cellular responses of human mesenchymal stem cells via in-vitro functional assays. Finite element analysis revealed the homogeneous delivery of electric field in the bioreactor chamber with no detection of current density fluctuation in the proposed model. The custom-built bioreactor with capacitive stimulation delivery system features long-term stimulation with homogeneous electric field, biocompatible, sterilisable, scalable design and cost-effective in the manufacturing process. Using a continuous stimulation regime of 100 and 200 mV/mm on cp Ti discs, viability tests revealed up to an approximately 5-fold increase of cell proliferation rate as compared to non-stimulated controls. The human mesenchymal stem cells showed more elongated and differentiated morphology under this regime, with evidence of nuclear elongation and cytoskeletal orientation perpendicular to the direction of electric field. The continuous stimulation did not cause pH fluctuations and hydrogen peroxide production caused by Faradic reactions, signifying the suitability for long-term toxic free stimulation as opposed to the commonly used direct stimulation regime. An approximate of 4-fold increase in alkaline phosphatase production and approximately 9-fold increase of calcium deposition were observed on 200 mV/mm exposed samples relative to non-stimulated controls. It is worth noting that early stem cell differentiation and matrix production were observed under the said electric field even without the presence of chemical inductive growth factors. STATEMENT OF SIGNIFICANCE: This manuscript presents a study on combining pure titanium (primarily preferred as medical implant materials) and electrical stimulation in a purpose-built bioreactor with capacitive stimulation delivery system. A continuous capacitive stimulation regime on titanium disc has resulted in enhanced stem cell orientation, nuclei elongation, proliferation and differentiation as compared to non-stimulated controls. We believe that this manuscript creates a paradigm for future studies on the evolution of healthcare treatments in the area of targeted therapy on implantable and wearable medical devices through tailored innovative electrical stimulation approach, thereby influencing therapeutic conductive and electroactive biomaterials research prospects and development.
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Affiliation(s)
- Juan Shong Khaw
- The Henry Royce Institute, Royce Hub Building, The University of Manchester, Manchester M13 9PL, UK
| | - Ruikang Xue
- The Henry Royce Institute, Royce Hub Building, The University of Manchester, Manchester M13 9PL, UK
| | - Nigel J Cassidy
- Civil Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Sarah H Cartmell
- The Henry Royce Institute, Royce Hub Building, The University of Manchester, Manchester M13 9PL, UK.
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Wieja F, Jacobs G, Stein S, Kopp A, van Gaalen K, Kröger N, Zinser M. Development and validation of a parametric human mandible model to determine internal stresses for the future design optimization of maxillofacial implants. J Mech Behav Biomed Mater 2022; 125:104893. [PMID: 34715640 DOI: 10.1016/j.jmbbm.2021.104893] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/05/2021] [Accepted: 10/10/2021] [Indexed: 11/26/2022]
Abstract
Large segmental mandible bone defects still represent a challenge for endogenous regeneration. Despite the bone's capacity to heal in many clinical situations, bone defects over a critical size do not heal spontaneously. An emerging treatment of critically sized mandibular defects is the implantation of individually manufactured scaffolds consisting of biodegradable magnesium alloys. Biomedical engineers faced the challenge of developing a scaffold structure that not only provides sufficient stability, but also stimulates and promotes bone growth while considering the degradation of the magnesium alloy. The porosity of the scaffold must also support bone ingrowth and neovascularization. For an optimal design and subsequent structural optimization knowledge of external load cases is essential. However, currently the muscle and joint forces of the mandible cannot be measured directly. The aim of our study was therefore the development of a parametric human mandible model to determine the relevant boundary conditions for the subsequent structural optimization of individual jawbone implants. Using a model-based approach, determining the essential external load of the mandible as a function of the age and sex of a patient individually and the realistic simulation of the mechanical stress for patient-specific loads and anatomies has been realized. The developed model is successfully validated by evaluating the deformations and stresses of the lower jaw of a possible patient and comparing them with the results of dental research. Based on the results of the modelling, in a subsequent optimization process section forces at the interface between the bone tissue and jawbone implant can be determined and used to optimize the design of the jawbone implant.
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Affiliation(s)
- Franziska Wieja
- Institute for Machine Elements and Systems Engineering, RWTH Aachen University, 52062, Aachen, Germany.
| | - Georg Jacobs
- Institute for Machine Elements and Systems Engineering, RWTH Aachen University, 52062, Aachen, Germany
| | - Sebastian Stein
- Institute for Machine Elements and Systems Engineering, RWTH Aachen University, 52062, Aachen, Germany.
| | | | | | - Nadja Kröger
- Department of Plastic, Reconstructive and Aesthetic Surgery, University Hospital of Cologne, 50937, Cologne, Germany.
| | - Max Zinser
- Department of Plastic, Reconstructive and Aesthetic Surgery, University Hospital of Cologne, 50937, Cologne, Germany.
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Fernando PLN, Abeygunawardane A, Wijesinghe P, Dharmaratne P, Silva P. An engineering review of external fixators. Med Eng Phys 2021; 98:91-103. [PMID: 34848044 PMCID: PMC8660649 DOI: 10.1016/j.medengphy.2021.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 10/08/2021] [Accepted: 11/02/2021] [Indexed: 01/08/2023]
Abstract
Mechanical stability plays a key role in the effectiveness of external fixators. Strength and stiffness are the main factors which contributes towards stability. Modified configurations of linear, circular and hybrid fixators are investigated. Light weight composite materials are gradually replacing traditional metallic alloys. Existing research gaps in further optimizing external fixators are identified.
External Fixators are a common technique used to treat a variety of issues related to bones, predominantly due to its non-intrusive nature and versatility in terms of form and materials. While it is mainly used to treat open fractures, its other uses include limb lengthening, deformity correction, bone grafting, compression of non-unions and stabilization of dislocations. Its earliest use dates as far back as 400 BCE and has undergone significant improvements, focusing on both customization and optimization. These two aspects highlight the significance of complementing the orthopaedic requirements with engineering knowledge and its applications. Hence, this review paper aims to conduct an examination of recent developments of external fixators with a special focus on its structure, the usage of materials and biomechanical investigations using experimental and numerical techniques. The paper presents the existing level of engineering knowledge with regards to these aspects and identifies research gaps, which can improve the quality of the commonly used external fixators.
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Affiliation(s)
- P L N Fernando
- Centre for Biomedical Innovation, University of Moratuwa, Sri Lanka; Department of Mechanical Engineering, University of Moratuwa, Sri Lanka
| | | | | | | | - Pujitha Silva
- Centre for Biomedical Innovation, University of Moratuwa, Sri Lanka; Department of Electronic and Telecommunications Engineering, University of Moratuwa, Sri Lanka.
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Arjmandi M, Kelly PA, Thambyah A. The mechanical influence of bone spicules in the osteochondral junction: A finite element modelling study. Biomech Model Mechanobiol 2021; 20:2335-51. [PMID: 34468916 DOI: 10.1007/s10237-021-01510-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 08/13/2021] [Indexed: 10/20/2022]
Abstract
While much has been done to study how cartilage responds to mechanical loading, as well as modelling such responses, arguably less has been accomplished around the mechanics of the cartilage-bone junction. Previously, it has been reported that the presence of bony spicules invading the zone of calcified cartilage, preceded the formation of new subchondral bone and the advancing of the cement line (Thambyah and Broom in Osteoarthr Cartil 17:456-463, 2009). In this study, the morphology and frequency of bone spicules in the cartilage-bone interface of osteochondral beams subjected to three-point bending were modelled, and the results are discussed within the context of biomechanical theories on bone formation. It was found that the stress and strain magnitudes, and their distribution were sensitive to the presence and number of spicules. Spicule numbers and shape were shown to affect the strain energy density (SED) distribution in the areas of the cement line adjacent to spicules. Stresses, strains and SED analyses thus provided evidence that the mechanical environment with the addition of spicules promotes bone formation in the cartilage-bone junction.
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Benemerito I, Griffiths W, Allsopp J, Furnass W, Bhattacharya P, Li X, Marzo A, Wood S, Viceconti M, Narracott A. Delivering computationally-intensive digital patient applications to the clinic: An exemplar solution to predict femoral bone strength from CT data. Comput Methods Programs Biomed 2021; 208:106200. [PMID: 34107372 DOI: 10.1016/j.cmpb.2021.106200] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
BACKGROUND AND OBJECTIVE Whilst fragility hip fractures commonly affect elderly people, often causing permanent disability or death, they are rarely addressed in advance through preventive techniques. Quantification of bone strength can help to identify subjects at risk, thus reducing the incidence of fractures in the population. In recent years, researchers have shown that finite element models (FEMs) of the hip joint, derived from computed tomography (CT) images, can predict bone strength more accurately than other techniques currently used in the clinic. The specialised hardware and trained personnel required to perform such analyses, however, limits the widespread adoption of FEMs in clinical contexts. In this manuscript we present CT2S (Computed Tomography To Strength), a system developed in collaboration between The University of Sheffield and Sheffield Teaching Hospitals, designed to streamline access to this complex workflow for clinical end-users. METHODS The system relies on XNAT and makes use of custom apps based on open source software. Available through a website, it allows doctors in the healthcare environment to benefit from FE based bone strength estimation without being exposed to the technical aspects, which are concealed behind a user-friendly interface. Clinicians request the analysis of CT scans of a patient through the website. Using XNAT functionality, the anonymised images are automatically transferred to the University research facility, where an operator processes them and estimates the bone strength through FEM using a combination of open source and commercial software. Following the analysis, the doctor is provided with the results in a structured report. RESULTS The platform, currently available for research purposes, has been deployed and fully tested in Sheffield, UK. The entire analysis requires processing times ranging from 3.5 to 8 h, depending on the available computational power. CONCLUSIONS The short processing time makes the system compatible with current clinical workflows. The use of open source software and the accurate description of the workflow given here facilitates the deployment in other centres.
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Affiliation(s)
- I Benemerito
- INSIGNEO Institute for in silico Medicine, The University of Sheffield, UK; Department of Mechanical Engineering, The University of Sheffield, UK.
| | - W Griffiths
- INSIGNEO Institute for in silico Medicine, The University of Sheffield, UK; Department of Mechanical Engineering, The University of Sheffield, UK
| | - J Allsopp
- Sheffield Teaching Hospital Foundation Trust, Sheffield, UK
| | - W Furnass
- Department of Computer Science, The University of Sheffield, UK
| | - P Bhattacharya
- INSIGNEO Institute for in silico Medicine, The University of Sheffield, UK; Department of Mechanical Engineering, The University of Sheffield, UK
| | - X Li
- INSIGNEO Institute for in silico Medicine, The University of Sheffield, UK; Department of Mechanical Engineering, The University of Sheffield, UK
| | - A Marzo
- INSIGNEO Institute for in silico Medicine, The University of Sheffield, UK; Department of Mechanical Engineering, The University of Sheffield, UK
| | - S Wood
- Sheffield Teaching Hospital Foundation Trust, Sheffield, UK
| | - M Viceconti
- Department of Industrial Engineering, Alma Mater Studiorium, University of Bologna, Italy; Medical Technology Lab, IRCSS Istituto Ortopedico Rizzoli, Bologna, Italy
| | - A Narracott
- INSIGNEO Institute for in silico Medicine, The University of Sheffield, UK; Department of Infection, Immunity & Cardiovascular Disease, The University of Sheffield, UK
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Deliège L, Misier KR, Bozkurt S, Breakey W, James G, Ong J, Dunaway D, Jeelani NUO, Schievano S, Borghi A. Validation of an in-silico modelling platform for outcome prediction in spring assisted posterior vault expansion. Clin Biomech (Bristol, Avon) 2021; 88:105424. [PMID: 34303069 DOI: 10.1016/j.clinbiomech.2021.105424] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Spring-Assisted Posterior Vault Expansion has been adopted at Great Ormond Street Hospital for Children, London, UK to treat raised intracranial pressure in patients affected by syndromic craniosynostosis, a congenital calvarial anomaly which causes premature fusion of skull sutures. This procedure aims at normalising head shape and augmenting intracranial volume by means of metallic springs which expand the back portion of the skull. The aim of this study is to create and validate a 3D numerical model able to predict the outcome of spring cranioplasty in patients affected by syndromic craniosynostosis, suitable for clinical adoption for preoperative surgical planning. METHODS Retrospective spring expansion measurements retrieved from x-ray images of 50 patients were used to tune the skull viscoelastic properties for syndromic cases. Pre-operative computed tomography (CT) data relative to 14 patients were processed to extract patient-specific skull shape, replicate surgical cuts and simulate spring insertion. For each patient, the predicted finite element post-operative skull shape model was compared with the respective post-operative 3D CT data. FINDINGS The comparison of the sagittal and transverse cross-sections of the simulated end-of-expansion calvaria and the post-operative skull shapes extracted from CT images showed a good shape matching for the whole population. The finite element model compared well in terms of post-operative intracranial volume prediction (R2 = 0.92, p < 0.0001). INTERPRETATION These preliminary results show that Finite Element Modelling has great potential for outcome prediction of spring assisted posterior vault expansion. Further optimisation will make it suitable for clinical deployment.
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Affiliation(s)
- Lara Deliège
- UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK.
| | - Karan Ramdat Misier
- UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Selim Bozkurt
- UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - William Breakey
- UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Greg James
- UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Juling Ong
- Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, UK
| | - David Dunaway
- Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, UK
| | - N U Owase Jeelani
- Great Ormond Street Hospital, Great Ormond Street, London WC1N 3JH, UK
| | - Silvia Schievano
- UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
| | - Alessandro Borghi
- UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
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Keenan BE, Evans SL, Oomens CWJ. A review of foot finite element modelling for pressure ulcer prevention in bedrest: Current perspectives and future recommendations. J Tissue Viability 2021:S0965-206X(21)00070-X. [PMID: 34238649 DOI: 10.1016/j.jtv.2021.06.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 06/07/2021] [Accepted: 06/08/2021] [Indexed: 02/03/2023]
Abstract
Pressure ulcers (PUs) are a major public health challenge, having a significant impact on healthcare service and patient quality of life. Computational biomechanical modelling has enhanced PU research by facilitating the investigation of pressure responses in subcutaneous tissue and skeletal muscle. Extensive work has been undertaken on PUs on patients in the seated posture, but research into heel ulcers has been relatively neglected. The aim of this review was to address the key challenges that exist in developing an effective FE foot model for PU prevention and the confusion surrounding the wide range of outputs reported. Nine FE foot studies investigating heel ulcers in bedrest were identified and reviewed. Six studies modelled the posterior part of the heel, two included the calf and foot, and one modelled the whole body. Due to the complexity of the foot anatomy, all studies involved simplification or assumptions regarding parts of the foot structure, boundary conditions and material parameters. Simulations aimed to understand better the stresses and strains exhibited in the heel soft tissues of the healthy foot. The biomechanical properties of soft tissue derived from experimental measurements are critical for developing a realistic model and consequently guiding clinical decisions. Yet, little to no validation was reported in each of the studies. If FE models are to address future research questions and clinical applications, then sound verification and validation of these models is required to ensure accurate conclusions and prediction of patient outcomes. Recommendations and considerations for future FE studies are therefore proposed.
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Bansod YD, Kebbach M, Kluess D, Bader R, van Rienen U. Finite element analysis of bone remodelling with piezoelectric effects using an open-source framework. Biomech Model Mechanobiol 2021; 20:1147-1166. [PMID: 33740158 PMCID: PMC8154825 DOI: 10.1007/s10237-021-01439-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 02/17/2021] [Indexed: 12/16/2022]
Abstract
Bone tissue exhibits piezoelectric properties and thus is capable of transforming mechanical stress into electrical potential. Piezoelectricity has been shown to play a vital role in bone adaptation and remodelling processes. Therefore, to better understand the interplay between mechanical and electrical stimulation during these processes, strain-adaptive bone remodelling models without and with considering the piezoelectric effect were simulated using the Python-based open-source software framework. To discretise numerical attributes, the finite element method (FEM) was used for the spatial variables and an explicit Euler scheme for the temporal derivatives. The predicted bone apparent density distributions were qualitatively and quantitatively evaluated against the radiographic scan of a human proximal femur and the bone apparent density calculated using a bone mineral density (BMD) calibration phantom, respectively. Additionally, the effect of the initial bone density on the resulting predicted density distribution was investigated globally and locally. The simulation results showed that the electrically stimulated bone surface enhanced bone deposition and these are in good agreement with previous findings from the literature. Moreover, mechanical stimuli due to daily physical activities could be supported by therapeutic electrical stimulation to reduce bone loss in case of physical impairment or osteoporosis. The bone remodelling algorithm implemented using an open-source software framework facilitates easy accessibility and reproducibility of finite element analysis made.
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Affiliation(s)
- Yogesh Deepak Bansod
- Institute of General Electrical Engineering, University of Rostock, 18051 Rostock, Germany
| | - Maeruan Kebbach
- Department of Orthopaedics, University Medicine Rostock, 18057 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
| | - Daniel Kluess
- Department of Orthopaedics, University Medicine Rostock, 18057 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
| | - Rainer Bader
- Department of Orthopaedics, University Medicine Rostock, 18057 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
- Department Ageing of Individuals and Society, University of Rostock, 18051 Rostock, Germany
| | - Ursula van Rienen
- Institute of General Electrical Engineering, University of Rostock, 18051 Rostock, Germany
- Department Life, Light & Matter, University of Rostock, 18051 Rostock, Germany
- Department Ageing of Individuals and Society, University of Rostock, 18051 Rostock, Germany
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Shirzad M, Zolfagharian A, Matbouei A, Bodaghi M. Design, evaluation, and optimization of 3D printed truss scaffolds for bone tissue engineering. J Mech Behav Biomed Mater 2021; 120:104594. [PMID: 34029944 DOI: 10.1016/j.jmbbm.2021.104594] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/08/2021] [Accepted: 05/11/2021] [Indexed: 11/18/2022]
Abstract
One of tissue engineering's main goals is to fabricate three-dimensional (3D) scaffolds with interconnected pores to reconstruct and regenerate damaged or deformed tissues and organs. In this regard, 3D printing is a promising technique for the fabrication of tissue scaffolds, which can precisely make predetermined and complicated architectures. This study aims to investigate and optimize the physical, mechanical, and biological properties of 3D truss architecture tissue scaffolds with different pore geometries. The mechanical properties of poly (methyl methacrylate) scaffolds are analysed experimentally and numerically. Furthermore, the mechanical and physical properties of scaffolds are optimized with response surface methodology (RSM), and cell adhesion of the 3D truss scaffold studies. Results demonstrate that mechanical properties of the simple and gradient scaffolds have different mechanical behaviors that are strongly correlated with pore size and their architectures, rather than merely the values of the porosity. It is also observed that the RSM technique can enable designers to enhance mechanical and physical properties of scaffolds at low cost. Moreover, the results of biological behaviour can endorse the reliability of 3D truss architecture in bone tissue engineering.
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Affiliation(s)
- M Shirzad
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK
| | - A Zolfagharian
- School of Engineering, Deakin University, Geelong, VIC, 3216, Australia
| | - A Matbouei
- Department of Energy Technology, Aalborg University, Aalborg, Denmark
| | - M Bodaghi
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, NG11 8NS, UK.
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Chua JQI, Srinivasan DV, Idapalapati S, Miserez A. Fracture toughness of the stomatopod dactyl club is enhanced by plastic dissipation: A fracture micromechanics study. Acta Biomater 2021; 126:339-49. [PMID: 33727196 DOI: 10.1016/j.actbio.2021.03.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 11/21/2022]
Abstract
The dactyl club of stomatopods is a biological hammer used to strike on hard-shell preys. To serve its function, the club must be imparted with a high tolerance against both contact stresses and fracture. While the contact mechanics of the club has been established, fracture toughness characterization has so far remained more elusive and semi-quantitative using nanoindentation fracture methods. Here, we used microcantilever fracture specimens with a chevron-notched crack geometry to quantitatively evaluate the fracture response of the impact region of dactyl clubs. The chevron-notched geometry was selected as it minimizes surface-related artefacts due to ion milling, and further allows to carry out fracture tests on samples free of pre-cracks with stable crack propagation even for brittle materials. Both linear elastic as well as elastic-plastic fracture mechanics methods, together with finite element modelling, were employed to analyse the fracture data. We find that crack-tip plastic dissipation is the main mechanism contributing to the fracture properties of the dactyl club material. Our study also suggests that the chevron-notched crack geometry is a suitable method to quantitatively assess the fracture toughness of hard biological materials. STATEMENT OF SIGNIFICANCE: Characterizing the fracture resistance of biomineralized structures is essential to draw their structure-properties relationships. Yet measuring the fracture properties of such materials is often hampered by their small size and irregular shape. Indentation fracture is used to circumvent these issues but does not discriminate between the elastic and elastic-plastic contributions to the fracture resistance. The dactyl club "hammer" of mantis shrimps is a biological material whose fracture properties are central to its function. A microfracture study was conducted using microcantilever specimens with chevron-notched crack geometry to assess the fracture toughness. Adopting linear elastic and elastic-plastic fracture mechanics protocols, we find that plastic dissipation is the major contribution to the fracture response of the hypermineralized impact region of the dactyl club.
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Zara B, Polgár M, Sipos G, Dóka G, Gogate P, Djokovic V, Csóka L. Effect of hydrodynamic cavitation water treatment on Pseudomonas aeruginosa quorum-sensing molecules. Environ Sci Pollut Res Int 2021; 28:26182-26186. [PMID: 33855663 DOI: 10.1007/s11356-021-13930-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 04/09/2021] [Indexed: 06/12/2023]
Abstract
Hydrodynamic cavitation treatment was used for the functional inactivation of quorum-sensing lactone molecules of Pseudomonas aeruginosa. Hydroxyl radicals formed as well as the shear effects during the cavitation process induced the inactivation of the signal molecules through hydrolysis reaction coupled with bacterial destruction. Concentration of two different types of homoserine lactones (HSL) molecules was tested after the treatment at various rotational speeds. It was found that the strongest effects can be achieved at speeds > 2000 rpm. This value is considered as an onset speed of dominant cavitation, and it is in agreement with literature data. The experimental trends were in agreement with the calculations based on the finite element modelling, which show a significant increase in average shear stress at higher rotational speeds. Overall, the work has demonstrated the possible effects of hydrodynamic cavitation on the quorum-sensing molecules of Pseudomonas aeruginosa for the first time.
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Affiliation(s)
- Bernadett Zara
- Institute of Wood Based Products and Technologies, Károly Simonyi Faculty, University of Sopron, Sopron, 9400, Hungary
| | - Máté Polgár
- Institute of Wood Based Products and Technologies, Károly Simonyi Faculty, University of Sopron, Sopron, 9400, Hungary
- Aqua-Filt Ltd., Sopron, 9400, Hungary
| | - György Sipos
- Functional Genomics and Bioinformatics Group, Research Center for Forestry and Wood Industry, University of Sopron, Sopron, 9400, Hungary
| | | | - Parag Gogate
- Department of Chemical Engineering, Institute of Chemical Technology, Matunga, Mumbai, 400 019, India
| | - Vladimir Djokovic
- VINČA Institute of Nuclear Sciences-National Institute of thе Republic of Serbia, University of Belgrade, P.O. Box 522, Belgrade, 11001, Serbia
| | - Levente Csóka
- Institute of Cellulose and Paper Technology, Celltech-Paper Ltd., Sopron, 9400, Hungary.
- ELTE Eötvös Loránd University, Faculty of Informatics, Budapest, 1053, Hungary.
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Toh SMS, Ashkanfar A, English R, Rothwell G. Computational method for bearing surface wear prediction in total hip replacements. J Mech Behav Biomed Mater 2021; 119:104507. [PMID: 33862425 DOI: 10.1016/j.jmbbm.2021.104507] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 03/22/2021] [Accepted: 04/01/2021] [Indexed: 11/30/2022]
Abstract
Total hip replacement (THR) is a revolutionary treatment when a hip joint becomes severely damaged. Wear is known as one of the main reasons for THR failure. Current experimental techniques to investigate the wear at the bearing surfaces of THRs are time-consuming, complicated and expensive. In this study, an in-house fretting wear algorithm has been further developed to investigate the wear damage that occurs on bearing surfaces of THRs and its consequence on the longevity of the implants. A 3D finite element model has been created with a 36 mm diameter Cobalt-Chromium femoral head and a 4 mm thick cross-linked polyethylene bearing liner. A gait loading cycle was used to simulate walking for up to 5 million cycles (Mc). The wear algorithm extracts relative displacements and contact shear stresses from the finite element package to predict the linear and volumetric wear rates. This method is shown to have modelled the evolution of wear effectively and found it to be similar to those from experimental analyses. The linear and volumetric wear per million cycles predicted in this study were 0.0375mm/Mc and 33.6mm3/Mc which are comparable to those measured in-vivo THRs. The wear patterns obtained from this study are also comparable to the wear patterns shown on available conventional polyethylene liners. This method can be used to further aid in the design and clinical technique to reduce wear rate in THRs.
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Affiliation(s)
- Shawn Ming Song Toh
- School of Engineering, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK.
| | - Ariyan Ashkanfar
- School of Engineering, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Russell English
- School of Engineering, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
| | - Glynn Rothwell
- School of Engineering, Liverpool John Moores University, Byrom Street, Liverpool, L3 3AF, UK
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Jiang H, Robinson DL, Nankervis A, Garland SM, Callegari ET, Price S, Lee PVS, Wark JD. Bone Measures by Dual-Energy X-Ray Absorptiometry and Peripheral Quantitative Computed Tomography in Young Women With Type 1 Diabetes Mellitus. J Clin Densitom 2021; 24:259-267. [PMID: 32586681 DOI: 10.1016/j.jocd.2020.05.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/21/2020] [Accepted: 05/22/2020] [Indexed: 12/16/2022]
Abstract
Understanding bone fragility in young adult females with type 1 diabetes mellitus (T1DM) is of great clinical importance since the high fracture risk in this population remains unexplained. This study aimed to investigate bone health in young adult T1DM females by comparing relevant variables determined by dual-energy X-ray absorptiometry (DXA), peripheral quantitative computed tomography (pQCT) at the tibia and pQCT-based finite element analysis (pQCT-FEA) between T1DM subjects (n = 21) and age-, height- and weight-matched controls (n = 63). Tibial trabecular density (lower by 7.1%; 228.8 ± 33.6 vs 246.4 ± 31.8 mg/cm3, p = 0.02) and cortical thickness (lower by 7.3%; 3.8 ± 0.5 vs 4.1 ± 0.5 cm, p = 0.03) by pQCT were significantly lower in T1DM subjects than in controls. Tibial shear stiffness by pQCT-FEA was also lower in T1DM subjects than in controls at both the 4% site (by 17.1%; 337.4 ± 75.5 vs 407.1 ± 75.4 kN/mm, p < 0.01) and 66% site (by 7.9%; 1113.0 ± 158.6 vs 1208.8 ± 161.8 kN/mm, p = 0.03). These differences remained statistically significant after adjustment for confounding factors. No difference between groups was observed in DXA-determined variables (all p ≥ 0.08), although there was a trend towards lower aBMD at the lumbar spine in T1DM subjects than in controls after adjustment for confounders (p = 0.053). These novel findings elicited using pQCT and pQCT-FEA suggest a clinically significant impact of T1DM on bone strength in young adult females with T1DM. Peripheral QCT and pQCT-FEA may provide more information than DXA alone on bone fragility in this population. Further longitudinal studies with a larger sample size are warranted to understand the evolution and causes of bone fragility in young T1DM females.
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Affiliation(s)
- Hongyuan Jiang
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
| | - Dale L Robinson
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Australia
| | - Alison Nankervis
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia; Diabetes Service, Royal Women's Hospital, Melbourne, Australia; Department of Diabetes and Endocrinology, Royal Melbourne Hospital, Melbourne, Australia
| | - Suzanne M Garland
- Centre for Women's Infectious Diseases Research, Royal Women's Hospital, Melbourne, Australia; Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, Australia; Infection & Immunity, Murdoch Children's Research Institute, Melbourne, Australia
| | - Emma T Callegari
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia
| | - Sarah Price
- Department of Diabetes and Endocrinology, Royal Melbourne Hospital, Melbourne, Australia
| | - Peter V S Lee
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Australia
| | - John D Wark
- Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Melbourne, Australia; Bone and Mineral Medicine, Royal Melbourne Hospital, Melbourne, Australia; Department of Diabetes and Endocrinology, Royal Melbourne Hospital, Melbourne, Australia.
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Fridgeirsson EA, Deng ZD, Denys D, van Waarde JA, van Wingen GA. Electric field strength induced by electroconvulsive therapy is associated with clinical outcome. Neuroimage Clin 2021; 30:102581. [PMID: 33588322 PMCID: PMC7895836 DOI: 10.1016/j.nicl.2021.102581] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/31/2022]
Abstract
The clinical effect of electroconvulsive therapy (ECT) is mediated by eliciting a generalized seizure, which is achieved by applying electrical current to the head via scalp electrodes. The anatomy of the head influences the distribution of current flow in each brain region. Here, we investigated whether individual differences in simulated local electrical field strength are associated with ECT efficacy. We modeled the electric field of 67 depressed patients receiving ECT. Patient's T1 magnetic resonance images were segmented, conductivities were assigned to each tissue and the finite element method was used to solve for the electric field induced by the electrodes. We investigated the correlation between modelled electric field and ECT outcome using voxel-wise general linear models. The difference between bilateral (BL) and right unilateral (RUL) electrode placement was striking. Even within electrode configuration, there was substantial variability between patients. For the modeled BL placement, stronger electric field strengths appeared in the left hemisphere and part of the right temporal lobe. Importantly, a stronger electric field in the temporal lobes was associated with less optimal ECT response in patients treated with BL-ECT. No significant differences in electric field distributions were found between responders and non-responders to RUL-ECT. These results suggest that overstimulation of the temporal lobes during BL stimulation has negative consequences on treatment outcome. If replicated, individualized pre-ECT computer-modelled electric field distributions may inform the development of patient-specific ECT protocols.
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Affiliation(s)
- Egill Axfjord Fridgeirsson
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands; Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands
| | - Zhi-De Deng
- Noninvasive Neuromodulation Unit, Experimental Therapeutics & Pathophysiology Branch, National Institute of Mental Health, United States
| | - Damiaan Denys
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands; The Netherlands Institute for Neuroscience, an Institute of the Royal Netherlands Academy of Arts and Sciences, Amsterdam, the Netherlands
| | | | - Guido A van Wingen
- Department of Psychiatry, Amsterdam UMC, University of Amsterdam, Amsterdam Neuroscience, Amsterdam, the Netherlands; Amsterdam Brain and Cognition, University of Amsterdam, Amsterdam, the Netherlands.
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Pickering E, Silva MJ, Delisser P, Brodt MD, Gu Y, Pivonka P. Estimation of load conditions and strain distribution for in vivo murine tibia compression loading using experimentally informed finite element models. J Biomech 2020; 115:110140. [PMID: 33348259 DOI: 10.1016/j.jbiomech.2020.110140] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/29/2020] [Accepted: 11/12/2020] [Indexed: 12/15/2022]
Abstract
The murine tibia compression model, is the gold standard for studying bone adaptation due to mechanical loading in vivo. Currently, a key limitation of the experimental protocol and associated finite element (FE) models is that the exact load transfer, and consequently the loading conditions on the tibial plateau, is unknown. Often in FE models, load is applied to the tibial plateau based on inferences from micro-computed tomography (μCT). Experimental models often use a single strain gauge to assess the three-dimensional (3D) loading state. However, a single strain gauge is insufficient to validate such FE models. To address this challenge, we develop an experimentally calibrated method for identifying the load application region on the tibial plateau based upon measurements from three strain gauges. To achieve this, axial compression was conducted on mouse tibiae (n=3), with strains gauges on three surfaces. FE simulations were performed to compute the strains at the gauge locations as a function of a variable load location. By minimising the error between experimental and FE strains, the precise load location was identified; this was found to vary between tibia specimens. It was further shown that commonly used FE loading conditions, found in literature, did not replicate the experimental strain distribution, highlighting the importance of load calibration. This work provides critical insights into how load is transferred to the tibial plateau. Importantly, this work develops an experimentally informed technique for loading the tibial plateau in FE models.
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Affiliation(s)
- Edmund Pickering
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia.
| | - Matthew J Silva
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, Washington University, Saint Louis, MO, USA; Department of Biomedical Engineering, Washington University, Saint Louis, MO, USA
| | - Peter Delisser
- University of Bristol School of Veterinary Science, Bristol, UK; Veterinary Specialist Services, Brisbane, QLD, Australia
| | - Michael D Brodt
- Department of Orthopaedic Surgery, Musculoskeletal Research Center, Washington University, Saint Louis, MO, USA
| | - YuanTong Gu
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia
| | - Peter Pivonka
- School of Mechanical, Medical and Process Engineering, Queensland University of Technology (QUT), Brisbane, QLD 4000, Australia
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Auenhammer RM, Mikkelsen LP, Asp LE, Blinzler BJ. Dataset of non-crimp fabric reinforced composites for an X-ray computer tomography aided engineering process. Data Brief 2020; 33:106518. [PMID: 33294516 PMCID: PMC7689367 DOI: 10.1016/j.dib.2020.106518] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/05/2020] [Accepted: 11/06/2020] [Indexed: 10/26/2022] Open
Abstract
This data in brief article describes a dataset used for an X-ray computer tomography aided engineering process consisting of X-ray computer tomography data and finite element models of non-crimp fabric glass fibre reinforced composites. Additional scanning electron microscope images are provided for the validation of the fibre volume fraction. The specimens consist of 4 layers of unidirectional bundles each supported by off-axis backing bundles with an average orientation on ±80° The finite element models, which were created solely on the image data, simulate the tensile stiffness of the samples. The data can be used as a benchmark dataset to apply different segmentation algorithms on the X-ray computer tomography data. It can be further used to run the models using different finite element solvers.
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Affiliation(s)
- Robert M Auenhammer
- Industrial and Materials Science, Chalmers University of Technology, SE-41296 Göteborg, Sweden.,Composite Materials, DTU Wind Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark
| | - Lars P Mikkelsen
- Composite Materials, DTU Wind Energy, Technical University of Denmark, DK-4000 Roskilde, Denmark
| | - Leif E Asp
- Industrial and Materials Science, Chalmers University of Technology, SE-41296 Göteborg, Sweden
| | - Brina J Blinzler
- Industrial and Materials Science, Chalmers University of Technology, SE-41296 Göteborg, Sweden
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Stadelmann MA, Schenk DE, Maquer G, Lenherr C, Buck FM, Bosshardt DD, Hoppe S, Theumann N, Alkalay RN, Zysset PK. Conventional finite element models estimate the strength of metastatic human vertebrae despite alterations of the bone's tissue and structure. Bone 2020; 141:115598. [PMID: 32829037 PMCID: PMC9206866 DOI: 10.1016/j.bone.2020.115598] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 06/05/2020] [Accepted: 08/12/2020] [Indexed: 01/02/2023]
Abstract
INTRODUCTION Pathologic vertebral fractures are a major clinical concern in the management of cancer patients with metastatic spine disease. These fractures are a direct consequence of the effect of bone metastases on the anatomy and structure of the vertebral bone. The goals of this study were twofold. First, we evaluated the effect of lytic, blastic and mixed (both lytic and blastic) metastases on the bone structure, on its material properties, and on the overall vertebral strength. Second, we tested the ability of bone mineral content (BMC) measurements and standard FE methodologies to predict the strength of real metastatic vertebral bodies. METHODS Fifty-seven vertebral bodies from eleven cadaver spines containing lytic, blastic, and mixed metastatic lesions from donors with breast, esophageal, kidney, lung, or prostate cancer were scanned using micro-computed tomography (μCT). Based on radiographic review, twelve vertebrae were selected for nanoindentation testing, while the remaining forty-five vertebrae were used for assessing their compressive strength. The μCT reconstruction was exploited to measure the vertebral BMC and to establish two finite element models. 1) a micro finite element (μFE) model derived at an image resolution of 24.5 μm and 2) homogenized FE (hFE) model derived at a resolution of 0.98 mm. Statistical analyses were conducted to measure the effect of the bone metastases on BV/TV, indentation modulus (Eit), ratio of plastic/total work (WPl/Wtot), and in vitro vertebral strength (Fexp). The predictive value of BMC, μFE stiffness, and hFE strength were evaluated against the in vitro measurements. RESULTS Blastic vertebral bodies exhibit significantly higher BV/TV compared to the mixed (p = 0.0205) and lytic (p = 0.0216) vertebral bodies. No significant differences were found between lytic and mixed vertebrae (p = 0.7584). Blastic bone tissue exhibited a 5.8% lower median Eit (p< 0.001) and a 3.3% lower median Wpl/Wtot (p<0.001) compared to non-involved bone tissue. No significant differences were measured between lytic and non-involved bone tissues. Fexp ranged from 1.9 to 13.8 kN, was strongly associated with hFE strength (R2=0.78, p< 0.001) and moderately associated with BMC (R2=0.66, p< 0.001) and μFE stiffness (R2=0.66, p< 0.001), independently of the lesion type. DISCUSSION Our findings show that tumour-induced osteoblastic metastases lead to slightly, but significantly lower bone tissue properties compared to controls, while osteolytic lesions appear to have a negligible impact. These effects may be attributed to the lower mineralization and woven nature of bone forming in blastic lesions whilst the material properties of bone in osteolytic vertebrae appeared little changed. The moderate association between BMC- and FE-based predictions to fracture strength suggest that vertebral strength is affected by the changes of bone mass induced by the metastatic lesions, rather than altered tissue properties. In a broader context, standard hFE approaches generated from CTs at clinical resolution are robust to the lesion type when predicting vertebral strength. These findings open the door for the development of FE-based prediction tools that overcomes the limitations of BMC in accounting for shape and size of the metastatic lesions. Such tools may help clinicians to decide whether a patient needs the prophylactic fixation of an impending fracture.
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Affiliation(s)
- Marc A Stadelmann
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010 Bern, Switzerland
| | - Denis E Schenk
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010 Bern, Switzerland
| | - Ghislain Maquer
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010 Bern, Switzerland
| | - Christopher Lenherr
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010 Bern, Switzerland
| | - Florian M Buck
- University of Zurich & MRI Schulthess Clinic, Zurich, Switzerland
| | - Dieter D Bosshardt
- Robert K. Schenk Laboratory of Oral Histology, School of Dental Medicine, University of Bern, Switzerland
| | - Sven Hoppe
- Department of Orthopedic Surgery, Inselspital, Bern University Hospital, Switzerland
| | | | - Ron N Alkalay
- Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, USA
| | - Philippe K Zysset
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010 Bern, Switzerland.
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Matsumura Y, Jafarpour M, Ramm SA, Reinhold K, Gorb SN, Rajabi H. Material heterogeneity of male genitalia reduces genital damage in a bushcricket during sperm removal behaviour. Naturwissenschaften 2020; 107:52. [PMID: 33241454 PMCID: PMC7688094 DOI: 10.1007/s00114-020-01706-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 11/03/2020] [Accepted: 11/07/2020] [Indexed: 02/03/2023]
Abstract
Sperm removal behaviour (SRB) is known in many animals, and male genital structures are often involved in the SRB, e.g. rubbing female genitalia vigorously. However, it remains unclear how those male genital structures function properly without severe genital damage during SRB. In the present study, we focused on the bushcricket Metaplastes ornatus and examined the biomechanics of male and female genital structures, involved in their SRB as a model case. During an initial phase of mating, males of this species thrust their subgenital plate with hook-like spurs and many microscopic spines into the female genital chamber. By moving the subgenital plate back-and-forth, males stimulate females, and this stimulation induces the ejection of sperm previously stored in females. We aimed to uncover the mechanics of the interaction between the subgenital plate and genital chamber during SRB. The genital morphology and its material composition were investigated using modern imaging and microscopy techniques. The obtained results showed a pronounced material heterogeneity in the subgenital plate and the genital chamber. The material heterogeneity was completely absent in that of a second bushcricket species, Poecilimon veluchianus, which does not exhibit SRB. Finite element simulations showed that the specific material heterogeneity can redistribute the stress in the subgenital plate of M. ornatus and, thereby, reduces stress concentration during SRB. This may explain why only a few examined males had a broken spur. We suggest that the observed structural features and material heterogeneity in M. ornatus are adaptations to their SRB.
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Affiliation(s)
- Yoko Matsumura
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany.
| | - Mohsen Jafarpour
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany
| | - Steven A Ramm
- Department of Evolutionary Biology, Bielefeld University, Konsequenz 45, 33615, Bielefeld, Germany
| | - Klaus Reinhold
- Department of Evolutionary Biology, Bielefeld University, Konsequenz 45, 33615, Bielefeld, Germany
| | - Stanislav N Gorb
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany
| | - Hamed Rajabi
- Department of Functional Morphology and Biomechanics, Zoological Institute, Kiel University, Am Botanischen Garten 1-9, 24118, Kiel, Germany
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Xu W, Yu A, Lu X, Tamaddon M, Wang M, Zhang J, Zhang J, Qu X, Liu C, Su B. Design and performance evaluation of additively manufactured composite lattice structures of commercially pure Ti (CP-Ti). Bioact Mater 2021; 6:1215-22. [PMID: 33210019 DOI: 10.1016/j.bioactmat.2020.10.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 10/10/2020] [Accepted: 10/10/2020] [Indexed: 12/15/2022] Open
Abstract
Ti alloys with lattice structures are garnering more and more attention in the field of bone repair or regeneration due to their superior structural, mechanical, and biological properties. In this study, six types of composite lattice structures with different strut radius that consist of simple cubic (structure A), body-centered cubic (structure B), and edge-centered cubic (structure C) unit cells are designed. The designed structures are firstly simulated and analysed by the finite element (FE) method. Commercially pure Ti (CP–Ti) lattice structures with optimized unit cells and strut radius are then fabricated by selective laser melting (SLM), and the dimensions, microtopography, and mechanical properties are characterised. The results show that among the six types of composite lattice structures, combined BA, CA, and CB structures exhibit smaller maximum von-Mises stress, indicating that these structures have higher strength. Based on the fitting curves of stress/specific surface area versus strut radius, the optimized strut radius of BA, CA, and CB structures is 0.28, 0.23, and 0.30 mm respectively. Their corresponding compressive yield strength and compressive modulus are 42.28, 30.11, and 176.96 MPa, and 4.13, 2.16, and 7.84 GPa, respectively. The CP-Ti with CB unit structure presents a similar strength and compressive modulus to the cortical bone, which makes it a potential candidate for subchondral bone restorations. Six types of graded lattice structures with different strut radius are designed and simulated by the FE method. BA, CA, and CB structures exhibit smaller maximum Von-Mises stress among six type structures. CP-Ti with CB structures exhibits similar mechanical properties to the cortical bone. Excellent properties make CP-Ti with CB structures an attractive subchondral bone restoration material.
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Atthapreyangkul A, Hoffman M, Pearce G. Effect of geometrical structure variations on the viscoelastic and anisotropic behaviour of cortical bone using multi-scale finite element modelling. J Mech Behav Biomed Mater 2020; 113:104153. [PMID: 33125948 DOI: 10.1016/j.jmbbm.2020.104153] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 10/10/2020] [Accepted: 10/21/2020] [Indexed: 11/25/2022]
Abstract
Multi-scale finite element analysis is performed to ascertain the effect of geometrical changes at multiple structural scales on the mechanical properties of cortical bone. Finite element models are developed, with reference to experimental data from existing literature, to account for bone's viscoelastic behaviour and anisotropic structure from the most fundamental level of bone consisting of mineralised collagen fibrils, up to the macroscopic level consisting of osteons and the Haversian canals. A statistical approach is incorporated to perform sensitivity analyses on the effects of different geometrical parameters on the effective material properties of cortical bone at each length scale. Numerical results indicate that there is an exponential correlation between the mineral volume fraction and the effective stiffness constants at each length scale. This contributes to the exponential behaviour of the instantaneous moduli describing cortical bone's two-phase stress relaxation process: a fast and slow response relaxation behaviour. Results indicate that the fast response relaxation time is independent of bone's structural anisotropy, whilst being dependent on variations in the global mineral volume fraction between length scales. However, the slow response relaxation time is independent of the changes in mineral volume fraction. It is also observed that the slow response relaxation time varies with bone's anisotropic structure, and therefore, contributes to the anisotropic properties of bone.
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Affiliation(s)
| | - Mark Hoffman
- School of Materials Science and Engineering, UNSW, Sydney, NSW, 2052, Australia; School of Mechanical and Manufacturing Engineering, UNSW, Sydney, NSW, 2052, Australia; School of Engineering, The University of Newcastle, NSW, 2308, Australia.
| | - Garth Pearce
- School of Mechanical and Manufacturing Engineering, UNSW, Sydney, NSW, 2052, Australia
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