Book of Abstracts 15th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering and 3rd Conference on Imaging and Visualization

In this edition, the two events will run together as a single conference, highlighting the strong connection with the Taylor & Francis journals: Computer Methods in Biomechanics and Biomedical Engineering (John Middleton and Christopher Jacobs, Eds.) and Computer Methods in Biomechanics and Biomedical Engineering: Imaging and Visualization (JoãoManuel R.S. Tavares, Ed.). The conference has become a major international meeting on computational biomechanics, imaging andvisualization. In this edition, the main program includes 212 presentations. In addition, sixteen renowned researchers will give plenary keynotes, addressing current challenges in computational biomechanics and biomedical imaging. In Lisbon, for the first time, a session dedicated to award the winner of the Best Paper in CMBBE Journal will take place. We believe that CMBBE2018 will have a strong impact on the development of computational biomechanics and biomedical imaging and visualization, identifying emerging areas of research and promoting the collaboration and networking between participants. This impact is evidenced through the well-known research groups, commercial companies and scientific organizations, who continue to support and sponsor the CMBBE meeting series. In fact, the conference is enriched with five workshops on specific scientific topics and commercial software.info:eu-repo/semantics/draf

A hybrid method to characterise the mechanical behaviour of biological hyper-elastic tissues

The characterisation of biological tissues has become high interest area in recent years, due to the grow uses and development of artificial soft tissues implants. These tissues present a nonlinear mechanical behaviour, which highly differs from typical engineering materials. This aspect brings us an enormous difficulty in characterisation of soft tissues and thus required the development of new experimental techniques associated with new numerical algorithms. This work presents the mechanical characterisation of human vaginal mucosa based on a hybrid technique that combines the experimental measurement of displacement field, acquired during a tensile test with numerical simulation, using material constitutive laws. The digital image correlation technique was used for high spatial resolution measurement of the displacements field on the hyper-elastic biological tissues. Several numerical simulations were carryout based on finite element commercial package, Ansys®, by combining the experimental displacements with different hyper-elastic models, which were developed from the experimental tensile test. Fluid release from specimen was observed during the tensile test, producing speckle decorrelation and, therefore, lack of information in displacement field. This problem was overcome by extrapolating data at the boundaries, through the application of special algorithm developed by the authors. The proposed hybrid method is shown to be more acquired then the numerical method based only on material constitutive models

Nonlinear effects in finite elements analysis of colorectal surgical clamping

Minimal Invasive Surgery (MIS) is a procedure that has increased its applications in past few years in different types of surgeries. As number of application fields are increasing day by day, new issues have been arising. In particular, instruments must be inserted through a trocar to access the abdominal cavity without capability of direct manipulation of tissues, so a loss of sensitivity occurs. Generally speaking, the student of medicine or junior surgeons need a lot of practice hours before starting any surgical procedure, since they have to difficulty in acquiring specific skills (hand–eye coordination among others) for this type of surgery. Here is what the surgical simulator present a promising training method using an approach based on Finite Element Method (FEM). The use of continuum mechanics, especially Finite Element Analysis (FEA) has gained an extensive application in medical field in order to simulate soft tissues. In particular, colorectal simulations can be used to understand the interaction between colon and the surrounding tissues and also between colon and instruments. Although several works have been introduced considering small displacements, FEA applied to colorectal surgical procedures with large displacements is a topic that asks for more investigations. This work aims to investigate how FEA can describe non-linear effects induced by material properties and different approximating geometries, focusing as test-case application colorectal surgery. More in detail, it shows a comparison between simulations that are performed using both linear and hyperelastic models. These different mechanical behaviours are applied on different geometrical models (planar, cylindrical, 3D-SS and a real model from digital acquisitions 3D-S) with the aim of evaluating the effects of geometric non-linearity. Final aim of the research is to provide a preliminary contribution to the simulation of the interaction between surgical instrument and colon tissues with multi-purpose FEA in order to help the preliminary set-up of different bioengineering tasks like force-contact evaluation or approximated modelling for virtual reality (surgical simulations). In particular, the contribution of this work is focused on the sensitivity analysis of the nonlinearities by FEA in the tissue-tool interaction through an explicit FEA solver. By doing in this way, we aim to demonstrate that the set-up of FEA computational surgical tools may be simplified in order to provide assistance to non-expert FEA engineers or medicians in more precise way of using FEA tools

Biomechanical Analyses of Posterior Vaginal Prolapse: MR Imaging and Computer Modeling Studies.

Pelvic organ prolapse is an abnormal downward displacement and deformation of the female pelvic organs. Because it adversely affects quality of life, over 200,000 operations are performed annually for prolapse in the U.S at a cost exceeding $1 billion. Approximately 87% of those procedures involve repair of a posterior vaginal prolapse, the etiology of which is a focus of this dissertation. But, because operative failure rates can approach 30%, new insights are needed as to how and why a posterior vaginal prolapse develops in the first place so that treatment can be improved. We hypothesize that the occurrence, size and type of posterior vaginal prolapse is not explained by failure of any single structure; rather it involves failure of connective tissue supports at two and possibly up to as many as 20 anatomical sites, along with impairment of the levator ani muscle. Using in vivo magnetic resonance imaging we first visualized the detailed 3-D pelvic floor anatomy of 84 healthy women. From these we then selected images from a pelvis of average dimensions and used them to create a detailed three-dimensional interactive model of the female pelvic floor complete with 23 structures. We then developed a method to measure and quantify the geometry of prolapse in forty 3-D magnetic resonance image-based models. Two main structures relating to the development of prolapse, fascia and apical vaginal supports, were then analyzed via two case-control studies. Finally, 2- and 3-D computer-based models were developed to identify the biomechanical interactions which lead to prolapse: levator muscle and connective tissue failure, and organ competition. These methodological approaches and computer models provide new insights into the biomechanical mechanisms underlying the development of posterior vaginal prolapse. Our hope is that they will lead to more effective surgical treatment strategies for this vexing condition.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/95942/1/jjluo_1.pd

Injury and Skeletal Biomechanics

This book covers many aspects of Injury and Skeletal Biomechanics. As the title represents, the aspects of force, motion, kinetics, kinematics, deformation, stress and strain are examined in a range of topics such as human muscles and skeleton, gait, injury and risk assessment under given situations. Topics range from image processing to articular cartilage biomechanical behavior, gait behavior under different scenarios, and training, to musculoskeletal and injury biomechanics modeling and risk assessment to motion preservation. This book, together with "Human Musculoskeletal Biomechanics", is available for free download to students and instructors who may find it suitable to develop new graduate level courses and undergraduate teaching in biomechanics