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Computer Methods in Biomechanics and Biomedical Engineering

Maxim Van den Abbeele, Jean-Marc Valiadis, Lucas V P C Lima, Pascal Khalifé, Philippe Rouch, Wafa Skalli
Although the use of pedicle screws is considered safe, mechanical issues still often occur. Commonly reported issues are screw loosening, screw bending and screw fracture. The aim of this study was to develop a Finite Element (FE) model for the study of pedicle screw biomechanics and for the prediction of the intraoperative pullout strength. The model includes both a parameterized screw model and a patient-specific vertebra model. Pullout experiments were performed on 30 human cadaveric vertebrae from ten donors...
December 10, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Łukasz Cyganik, Marcin Binkowski, Grzegorz Kokot, Paulina Cyganik, Tomasz Rusin, Filip Bolechała, Roman Nowak, Zygmunt Wróbel, Antoni John
The study presents an experimental verification of Wagner et al.'s relationship in microscale and proposes a modification of this relationship. For this purpose, 11 cubic specimens were microcomputed tomography scanned and mechanically tested with the displacement full-field measurements using a digital image correlation system. Then, numerical simulations of the compression tests were performed using a finite elements method. The Young's modulus distributions assigned to the finite elements models were calculated using both of Wagner et al...
November 23, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Mohammad Al-Amri, Hilal Al Balushi, Abdulrhman Mashabi
Self-paced treadmill walking is becoming increasingly popular for the gait assessment and re-education, in both research and clinical settings. Its day-to-day repeatability is yet to be established. This study scrutinised the test-retest repeatability of key gait parameters, obtained from the Gait Real-time Analysis Interactive Lab (GRAIL) system. Twenty-three male able-bodied adults (age: 34.56 ± 5.12 years) completed two separate gait assessments on the GRAIL system, separated by 5 ± 3 days. Key gait kinematic, kinetic, and spatial-temporal parameters were analysed...
November 23, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Carlo Massaroni, Guglielmo Senesi, Emiliano Schena, Sergio Silvestri
Breathing parameters can be measured by motion capture systems by placing photo-reflective markers on the chest wall. A computational model is mandatory to compute the breathing volume and to calculate temporal and kinematical features by the gathered markers trajectories. Despite different methods based on different geometrical approaches can be adopted to compute volumes, no information about their differences in the respiratory evaluation are available. This study investigated the performances of four methods (conventional, prism-based, convex hull with boundary condition, based on Delaunay triangulation) using an optoelectronic motion capture system, on twelve healthy participants during 30 s of breathing...
November 22, 2017: Computer Methods in Biomechanics and Biomedical Engineering
T O Lintern, M P Nash, P Kelly, F H Bloomfield, A J Taberner, P M F Nielsen
Abusive head trauma (AHT) is a potentially fatal result of child abuse, but the mechanisms by which injury occur are often unclear. To investigate the contention that shaking alone can elicit the injuries observed, effective computational models are necessary. The aim of this study was to develop a probabilistic model describing infant head kinematics in AHT. A deterministic model incorporating an infant's mechanical properties, subjected to different shaking motions, was developed in OpenSim. A Monte Carlo analysis was used to simulate the range of infant kinematics produced as a result of varying both the mechanical properties and the type of shaking motions...
November 21, 2017: Computer Methods in Biomechanics and Biomedical Engineering
A Girotti, F Rosa, M Ferrotto, P Girotti, U Pastorino
The Department of Thoracic Surgery of the National Institute of Cancer in Milan developed a new rib-cage prosthesis which tries to combine flexibility, protection and bio-compatibility. This new replacement concept has been implanted in many patients, showing cheering results in term of reconstructions simplicity, postoperative complications reduction and patients comfort. This paper investigates and discusses in detail the mechanical behavior of the innovative rib cage prosthesis. Mechanical strength and stiffness are numerically evaluated in order to asses its limits and if it is fully compatible with patients 'normal' life...
November 13, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Dilan Pathirana, Barbara Johnston, Peter Johnston
Coarctation of the Aorta is a congenital narrowing of the aorta. Two commonly used treatments are resection and end-to-end anastomosis, and stent placements. We simulate blood flow through one-dimensional models of aortas. Different artery stiffnesses, due to treatments, are included in our model, and used to compare blood flow properties in the treated aortas. We expand our previously published model to include the natural tapering of aortas. We look at change in aorta wall radius, blood pressure and blood flow velocity, and find that, of the two treatments, the resection and end-to-end anastomosis treatment more closely matches healthy aortas...
November 9, 2017: Computer Methods in Biomechanics and Biomedical Engineering
G Pizzichelli, B Kehlet, Ø Evju, B A Martin, M E Rognes, K A Mardal, E Sinibaldi
Intrathecal delivery is a procedure involving the release of therapeutic agents into the cerebrospinal fluid (CSF) hrough a catheter. It holds promise for treating high-impact central nervous system pathologies, for which systemic administration routes are ineffective. In this study we introduce a numerical model able to simultaneously account for solute transport in the fluid and in the spinal cord. Using a Discontinuous Galerkin method and a three-dimensional patient-specific geometry, we studied the effect of catheter position and angle on local spinal cord drug concentration...
November 2017: Computer Methods in Biomechanics and Biomedical Engineering
S J Ramos-Infante, M A Pérez
This work aimed to perform a detailed in vitro and in silico characterization of open-cell structures, which resemble trabecular bone, to elucidate osteoporosis failure mechanisms. Experimental and image-based computational methods were used to estimate Young's modulus and porosities of different open-cell structures (Sawbones; Malmö, Sweden). Three different open-cell structures with different porosities were characterized. Additionally, some open-cell structures were scanned using a microcomputed tomography system (μCT) to non-destructively predict specimen Young's modulus of the structures by developing voxel-based and tetrahedral finite element (FE) models...
November 8, 2017: Computer Methods in Biomechanics and Biomedical Engineering
M K Heljak, K J Kurzydlowski, W Swieszkowski
One important factor affecting the process of tissue regeneration is scaffold stiffness loss, which should be properly balanced with the rate of tissue regeneration. The aim of the research reported here was to develop a computer tool for designing the architecture of biodegradable scaffolds fabricated by melt-dissolution deposition systems (e.g. Fused Deposition Modeling) to provide the required scaffold stiffness at each stage of degradation/regeneration. The original idea presented in the paper is that the stiffness of a tissue engineering scaffold can be controlled during degradation by means of a proper selection of the diameter of the constituent fibers and the distances between them...
November 6, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Christian Klemt, Daniel Nolte, Grigorios Grigoriadis, Erica Di Federico, Peter Reilly, Anthony M J Bull
The labrum contributes to passive glenohumeral joint stability. Cadaveric studies have demonstrated that this has position and load dependency, which has not been quantified under physiological loads. This study aims to validate subject-specific finite element (FE) models against in vitro measurements of joint stability and to utilise the FE models to predict joint stability under physiological loads. The predicted stability values were within ± one standard deviation of experimental data and the FE models showed a reduction in stability of 10-15% with high, physiological, loads...
November 6, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Yikun Ni, Lizhen Wang, Xiaoyu Liu, Hongquan Zhang, Chia-Ying Lin, Yubo Fan
The uneven distributed microstructure featured with plate-like spongy bone in woodpecker's skull has been found to further help reduce the impact during woodpecker's pecking behavior. Therefore, this work was to investigate the micro-mechanical properties and composition on different sites of Great Spotted woodpecker's (GSW) skull. Different sites were selected on forehead, tempus and occiput, which were also compared with those of Eurasian Hoopoe (EH) and Lark birds (LB). Micro structural parameters assessed from micro computed tomography (μCT) occurred significantly difference between GSW, EH and LB...
November 1, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Daniel Krüger, Sandro Wartzack
Musculoskeletal multibody models are increasingly used to analyze and optimize physical interactions between humans and technical artifacts. Since interaction is conveyed by contact between the human body and the artifact, a computationally robust modeling approach for frictional contact forces is a crucial aspect. In this contribution, we propose a parametric contact model and formulate an associated force optimization problem to simultaneously estimate unknown muscle and contact forces in an inverse dynamic manner from a prescribed motion trajectory...
October 30, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Caecilia Charbonnier, Sylvain Chagué, Frank C Kolo, Victoria B Duthon, Jacques Menetrey
When estimating knee kinematics from skin markers and stereophotogrammetry, multi-body optimization (MBO) has provided promising results for reducing soft tissue artefacts (STA), but can still be improved. The goal of this study was to assess the performance of MBO with subject-specific knee models at high knee flexion angles (up to 110°) against knee joint kinematics measured by magnetic resonance imaging. Eight subjects were recruited. MBO with subject-specific knee models was more effective in compensating STA compared to no kinematic and spherical constraints, in particular for joint displacements...
October 26, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Helen Liley, Ju Zhang, Elwyn Firth, Justin Fernandez, Thor Besier
Population variance in bone shape is an important consideration when applying the results of subject-specific computational models to a population. In this letter, we demonstrate the ability of partial least squares regression to provide an improved shape prediction of the equine third metacarpal epiphysis, using two easily obtained measurements.
October 26, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Boris V Balakin, Erlend Farbu, Pawel Kosinski
The potential outcome of a surgical enlargement of internal nasal channels may be a complication of nasal breathing termed the Empty Nose Syndrome (ENS). ENS pathophysiology is not entirely understood because the expansion of air pathways would in theory ease inhalation. The present contribution is aimed at defining the biophysical markers responsible for ENS. Our study, conducted in silico, compares nasal aerodynamics in pre- and post-operative geometries acquired by means of computer tomography from the same individual...
October 24, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Ganesh Thiagarajan, Bruno Vizcarra, Venkata Bodapudi, Rachel Reed, Rasoul Seyedmahmoud, Yong Wang, Jeffrey P Gorski, Mary P Walker
The objectives of this project were to use finite element methods to determine how changes in the elastic modulus due to oral cancer therapeutic radiation alter the distribution of mechanical stresses in teeth and to determine if observed failures in irradiated teeth correlate with changes in mechanical stresses. A thin slice section finite element (FE) model was constructed from micro CT sections of a molar tooth using MIMICS and 3-Matic software. This model divides the tooth into three enamel regions, the dentin-enamel junction (DEJ) and dentin...
October 24, 2017: Computer Methods in Biomechanics and Biomedical Engineering
B Rodriguez-Vila, P Sánchez-González, I Oropesa, E J Gomez, D M Pierce
We propose a fully automated methodology for hexahedral meshing of patient-specific structures of the human knee obtained from magnetic resonance images, i.e. femoral/tibial cartilages and menisci. We select eight patients from the Osteoarthritis Initiative and validate our methodology using MATLAB on a laptop computer. We obtain the patient-specific meshes in an average of three minutes, while faithfully representing the geometries with well-shaped elements. We hope to provide a fundamentally different means to test hypotheses on the mechanisms of disease progression by integrating our patient-specific FE meshes with data from individual patients...
October 10, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Duo Wai-Chi Wong, Yan Wang, Tony Lin-Wei Chen, Aaron Kam-Lun Leung, Ming Zhang
Subtalar joint arthroereisis (SJA) has been introduced to control the hyperpronation in cases of flatfoot. The objective of this study is to evaluate the biomechanical consequence of SJA to restore the internal stress and load transfer to the intact state from the attenuated biomechanical condition induced by posterior tibial tendon dysfunction (PTTD). A three-dimensional finite element model of the foot and ankle complex was constructed based on clinical images of a healthy female (age 28 years, height 165 cm, body mass 54 kg)...
September 27, 2017: Computer Methods in Biomechanics and Biomedical Engineering
Elder Michael Andrango Castro, Svatava Konvickova, Matej Daniel, Zdenek Horak
The aim of our study was to identify potential critical levels of implantation of an osseointegrated prosthesis for above-knee amputees. The implant used was the OPRA system. It was inserted in the femur at four different amputation heights, characterized by their residual limb ratios (0.299, 0.44, 0.58 and 0.73). The stress and strain distribution was evaluated in the bone-implant system during walking, considering a body mass of 100 kg. Considerably high stimulus (11,489 με) in the tissue near the tip was found at the highest implantation level...
September 27, 2017: Computer Methods in Biomechanics and Biomedical Engineering
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