1,721,291 research outputs found
Frontiers in Bioengineering and Biotechnology
No full textFrontiers in Bioengineering and Biotechnology publishes articles across a wide research spectrum. The mission of the journal is to bring all relevant bioengineering and biotechnology areas together on a single platform
Medical Engineering and Physics
No full textMedical Engineering & Physics provides a forum for the publication of the latest developments in biomedical engineering, and reflects the essential multidisciplinary nature of the subject. The journal publishes in-depth critical reviews, scientific papers and communications of work which is at an earlier stage of development. Topics covered include clinical engineering, biomedical computing, biological systems, instrumentation, medical imaging technology, biomaterials, biomechanics and rehabilitation. Medical Engineering & Physics keeps both medical engineers and clinicians abreast of the latest applications of technology to health care.
Audience: Biomedical engineers, medical physicists, orthopaedic surgeons, medical technician
Acta Bioengineering and Biomechanics
No full textActa of Bioengineering and Biomechanics is a platform allowing presentation of investigations results, exchange of ideas and experiences among researchers with technical and medical background.
Papers published in Acta of Bioengineering and Biomechanics may cover a wide range of topics in biomechanics, including, but not limited to:
Tissue Biomechanics,
Orthopedic Biomechanics,
Biomaterials,
Sport Biomechanics
Journal for Mechanics in Medicine and Biology
No full textThis journal has as its objective the publication and dissemination of original research in all fields of mechanics in medicine and biology. The journal publishes original papers in English which contribute to an understanding of biomedical science of a nano- to macro-scale or an improvement of the methods and techniques of medical and clinical treatment by the application of advanced high technology. Papers may be theoretical (including computational), experimental or both. The journal will also publish occasional reviews of advance in a specific aspect of mechanics research in medicine and biology
Why Do We Need Both Numerical Models and in Vitro Experiments for the Pre-Clinical Validation of Prostheses?
No full textPre-clinical validation of implantable devices, including prostheses, generally aims at demonstrating that a new device offers some advantage compared to existing ones, while not introducing additional hazards. This process involves the assessment of a number of possible failure scenarios and claimed benefits, in order to obtain certification of the device (e.g. FDA or CE-mark), and to support its marketing strategy.While until the 90ies in vitro tests were regarded as the golden standard, nowadays the trend is to rely more and more on numerical models (chiefly Finite Element models, FE). The truth is that neither numerical models nor in vitro tests are self-sufficient. FE models require the support of in vitro tests for a number of reasons. First of all, to construct reliable FE models a number of input parameters are required (e.g. material properties, friction coefficients) that can only be measured experimentally. Furthermore, FE models, like any model, can only address the scenarios they are intended for, and cannot predict something that is totally unexpected: for this reason, some preliminary indication is mandatory from in vitro tests. Finally, FE models cannot be assumed true until this is proven by validation against in vitro measurements. At the same time, in vitroexperiments have several limitations that make them unsuitable in a number of cases, for which FE models are better suited. First of all, experiments need optimization, which can be performed efficiently using FE models. Secondly, experiments typically inspect the outer surface of the in vitro specimen. Finally, in vitro experiments are ineffective in exploring multiple similar conditions (sensitivity analysis).A possible paradigm for pre-clinical validation can be summarized as follows (Fig. 1): 1) Preliminary in vitro experiments should be performed on implants with a prototype of the prosthesis to understand which failure scenarios should be expected.2) Potential hazards must be identified. For each hazard, the probability of occurrence and the risk must be identified using either a top-down Fault Tree Analysis (FTA), or a bottom-up Failure Mode and Effect Analysis (FMEA).3) To assess the risk of occurrence of each mode of failure, the most appropriate approach must be chosen (either experimental, or numerical). For instance, in vitro experiments are necessary to: Preliminarily assess the intended implant performance, and explore possible failure modes.Measure the actual material properties and interface conditions.Perform tests on specimens that include a real bone, the typical uncertainty related to implantation (interface condition, press-fit), etc.Conversely, numerical models are advantageous to:Estimate biomechanical quantities (e.g. state of stress/strain) in regions that are not accessible experimentally.Explore the effect of design factors (material, surface finish, geometric features, etc), surgical factors (e.g. implant malpositioning) on the outcome. Predict the post-operative evolution of the implant over time, including progressive failure, tissue adaptation, etc.Therefore, in vitro experiments and numerical models should be designed concurrently, to enable maximal synergy. The aim of this paper is to illustrate a framework where numerical models and in vitro tests synergistically complement each other (Fig. 2)
21 - Validation of Finite Element Models
No full textWhile in natural sciences, empiricism is predominant, mathematical modeling is traditionally limited to induc- tive models that extrapolate from repeated experimental observations. The extreme specialization of research has slowly separated mathematical modeling skills from ex- perimental skills in most research groups, and it is not rare to see groups where only one of these skills is truly developed. This is a pity: the complexity involved with understanding the biomechanical behavior of the muscu- loskeletal system is overwhelming; to advance compre- hension, one should be ready to use every technique available
Applications in Orthopaedics
No full textThis chapter summarizes the application of biomechanics in orthopedics. An overview is provided of the applications of biomechanics to basic science. This includes understanding how the musculoskeletal system works and moves; measuring indicators of movement that can describe the state of health/disease of a subject; building models of the entire musculoskeletal system (or of a portion of it) to describe, interpret and predict its function under different conditions; measuring the mechanical and structural properties of organs of our musculoskeletal system alone, and in presence of an orthopedic device. Descriptions of the tools that can be used in vitro and in silico to measure/predict the most relevant mechanical quantities (forces, moments, strain, displacement, strength, mode of failure) in bony structures are provided. In the last part, the most applicative role of biomechanics is described: design and validation of orthopedic devices is an extremely relevant issue (both to manufacturers, practitioners and patients), which involves a great deal of biomechanical experiments and simulations
Anatomical reference frame to grant reproducible in vitro biomechanical testing of the human hemi-pelvis
No full textThe Effect of the Loading Rate on the Full-Field Strain Distribution on Intervertebral Discs
Full text linkContrasting results are reported when the spine is tested at different strain rates. Tissue specimens from the ligaments or the intervertebral discs (IVD, including annulus fibrosus and nucleus pulposus) exhibit higher stiffness and lower dissipation at high strain rates. Counterintuitively, when spine segments are tested at high rates, the hysteresis area and loop width increase. It is unclear how the load is shared between the different structures at different loading rates. The hypotheses of this study were: (i) As the IVD stiffens at higher loading rates, the strain distribution around the disc would be depend on the loading rate; (ii) Pre-conditioning attenuates the strain-rate dependency of the IVD, thus making differences in strain distribution smaller at the different rates. Six segments of three vertebrae (L4-L6) were extracted from porcine spines and tested in presso-flexion at different loading rates (reaching full load in 0.67s, 6.7s and 67s). The full-field strain maps were measured using digital image correlation on the surface of the IVDs from lateral. The posterior-to-anterior trends of the strain were computed in detail for each IVD, for each loading rate. The values and the direction of principal strain on the surface of the IVDs, vertebrae, and endplates remained unchanged at different rates. In the transition zone between IVD and vertebra, only slight differences due to the loading rate appeared but with no statistical significance. These findings will allow better understanding of the rate-dependent behaviour and failure of the IVD
Accuracy of the planned vs achieved position of a cementless hip stem: a finite element study
No full textThe implant of an hip stem into the femoral medullary cavity consists of three steps: the resection of the femoral head,
the rasping of the femoral canal and the placement of the stem. Priority for cemtless hip implants, in order to achieve a
good level of primary stability, is the accuracy with which the stem is positioned in the host bone. An erroneous initial
positioning could lead to the implant instability promoting the ultimate failure of the implant 1. Initial excessive relative
micromotions at the bone-implant interface may inhibit the bony in-growth and secondary long term fixation 2,3.
The final objective of the early researches along this line is to arrange a set of instruments to predict the primary
stability in the pre-operative planning moving toward a less and minimally invasive surgical technique. Nevetheless,
even assuming a perfect surgical planning, there is still the practical problem of correct positioning of the stem in the
femur during surgery.
Aim of the present study was to asses the sensitivity of the relative bone-implant micromotions, stresses and strains to
the implant position as planned and achieved by the surgeon respectively before and after the operation. For this
purpose, the subject-specific finite element (FE) model of a cadaveric femur, accounting for patient and surgeon, was
derived from pre-operative and post-operative CT scans. The overall aim was to verify if the pre-clinical planning
correctly matches the achieved implant stability conditions and hence if it can be considered as a powerful tool to train
the surgeon in taking the appropriate clinical decisions
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