Award given to; Hayley Wyatt To attend; 12 th International Symposium Computer Methods in Biomechanics and Biomedical Engineering Mövenpick Hotel, Amsterdam, The Netherlands Hosted by; The Biomedical Engineering Department of Eindhoven University of Technology Dates; Sunday 12 th Wednesday 15 th October 2014 Amount Awarded; 450 Title of conference presentation; Finite Element Modelling of Electrosurgical Vessel Sealing The conference concerned computational methods in biomechanics and biomedical engineering. The main topics covered at the conference included various finite element methods and applications, the characterisation of soft tissue, and mathematical models to simulate the behaviour of soft tissue, all of which were highly relevant to my research interests.
Background I recently completed my PhD at Cardiff University as part of the School of Engineering, Institute of Medical Engineering and Medical Physics. My research throughout my PhD focused on electrosurgical vessel sealing devices and soft tissue mechanics, with one of the main aims of the research, being to produce a finite element model to simulate blood vessel clamping and sealing. This work was presented at the 12 th International Symposium Computer Methods in Biomechanics and Biomedical Engineering (CMBBE), October 13 15, 2014 in Amsterdam. My presentation for the conference was titled Finite Element Modelling of Electrosurgical Vessel Sealing. A copy of the full conference abstract can be found at the end of this report. Conference The CMBBE conference is a major international symposium that focuses on a variety of computing methods including finite element simulations and the characterisation of soft tissue mechanics. As such it was an exceptionally relevant conference for my area of research, in which I am keen to develop my career. The conference lasted three days, and during this time I attended over 50 presentations as well as delivering a presentation myself. One presentation I attended, titled Patient-specific finite element modelling of the calf muscle under elastic compression using ultrasound elastography and magnetic resonance imaging, was a particularly interesting presentation as it relates to an avenue of research I am currently pursuing. Additionally sessions titled Mechanical characterisation and modelling of damage in soft tissue and Cardiovascular therapies, were both particularly relevant to the research I conducted as part of my PhD. Furthermore by having the opportunity to present at the conference I received valuable feedback on my work, and gained advice and guidance to allow myself to improve as a researcher, and improved my confidence in presenting my work to an expert community. I also took part in the evening program which included a drinks reception and the conference dinner on the ship called the Ocean Diva Futura. Attending the conference provided me with a great opportunity to network and presented many opportunities to form collaborations with universities and research groups from all over the world. This included starting to discuss a potential visit to the University of Auckland with the aim of developing research links, and spending time with the researchers from Saint-Étienne, discussing their research and receiving advice on research projects I am starting to undertake. Through networking at the conference it has allowed me to begin to form my own connections with researchers from institutions all over the world, something that will prove invaluable as I continue to develop my career in research and academia. Conference dinner aboard the Ocean Diva Futura
Knowledge Gained Through attending many presentations at the conference I have learnt about the most up to date research in the field of computational methods in biomedical engineering. It has highlighted many methods and techniques for both characterising and modelling soft tissue. For example a number of presentations focused on techniques used to characterise the material properties of skin, and whilst these techniques were discussed in terms of the skin, they would be applicable to other soft tissues. Additionally a number of novel modelling techniques were presented at the conference, with one of the main areas of interest being the material models researchers are currently using to model the behaviour of various soft tissues. The conference highlighted the current trends within this area, and also how existing material models were being modified to apply them to different areas within the field, and to take them forward into areas such as damage modelling. Additionally presenting my work gave me the opportunity to receive valuable feedback from my peers, allowing me to continue to improve the quality of my research. The presentation I delivered was well received and gave me confidence in my research, and also the opportunity to improve my presentation skills. The opportunities and experience I have gained from attending the conference will prove to be invaluable as I wish to continue my career as a researcher. Upon returning to Cardiff University, I passed on information about some of the presentations I saw to various colleagues throughout the engineering department. Cardiff has an excellent research group relating to biomechanics and biomedical engineering and therefore a number of presentations were relevant to colleagues and the information passed on has already proven to be beneficial. In addition, I have also passed on contact details of fellow researchers who attended the conference to my colleagues working in similar fields in the hope that more knowledge can be shared between them. Additional Activities Attending the conference also gave me the opportunity to experience the Dutch culture and spend some time exploring the wonderful city of Amsterdam. Throughout my time in Amsterdam I visited a cheese museum, saw the De Gooyer windmill, and went on a boat ride through the Dutch canals. I also took the time to explore some of the fantastic museums in the city, including the Van Gogh museum, where I saw many of his masterpieces including Sunflowers, and Almond Branches in Bloom.
Exploring the wonderful city of Amsterdam Future Plans From attending the conference I am already beginning to plan to attend the same conference next year in Montreal, 2015. I feel the opportunities and experiences I gained from attending this conference would be further expanded by attending the conference next year. This is definitely a conference I would recommend to others due to the high quality research presented and the excellent networking opportunities. Additionally I am currently in the process of developing plans to visit the research group at the University of Auckland, an opportunity that would not have arisen without attending the conference, through the support of SWIEET. Summary I wish to thank SWIEET for making it possible for me to attend the conference. It was a fantastic experience to attend such a major conference and to explore the city of Amsterdam. Through attending this conference I feel I have gained valuable further insight into the field of soft tissue mechanics and computational methods, and it has provided me with many ideas and goals for my future research. Additionally attending the conference gave me the opportunity to meet academics and researchers from all over the world, with the potential of forming future collaborations.
Conference Abstract Finite Element Modelling of Electrosurgical Vessel Sealing Hayley Wyatt, Jimmy Yang, Rhys Pullin, Sam Evans Electrosurgical vessel sealing devices are used to cut and seal blood vessels in a variety of surgical procedures, such as hysterectomies and have many benefits including reduced patient blood loss and operative time. Unfortunately there is significant variation in the quality of the seal produced, with vessel morphology being demonstrated to significantly affect the seal quality and thus the burst pressure. Previous studies have demonstrated that with an increase in elastin content there was a reduction in seal quality, with a significant difference between predominantly muscular and elastic vessels. The aim of this study was to produce a finite element model (FEM) to investigate the effect of vessel morphology on the electrosurgical vessel sealing process. An FEM was created using the FEBio software suite to investigate the effect of vessel morphology. The vessel wall was modelled using the Ogden model with two sets of material parameters, predominantly elastic and predominantly muscular, being used. The first stage of the model replicated both the circumferential and axial residual stresses. Following this the vessel was pressurised to 100mmHg, and then compressed using rigid bodies to replicate the device jaws, with complete lumen occlusion being achieved. Subsequently the area beneath the device jaws was constrained to remain in the same position, simulating the adhesion of the vessel wall and the formation of the seal. The device jaws were then removed from the blood vessel wall and the pressure on the inside of the vessel wall was slowly increased to replicate burst pressure testing. The results from the FEM demonstrated a difference in the strain distributions between the muscular and elastic vessel throughout the analysis. The elastic vessel showed areas of higher strain at the centre of the vessel wall for both the seal area and the vessel wall adjacent to the seal. This higher level of strain within the elastic vessel indicates that the elastic vessels fail at lower burst pressures due to large deformations within the vessel wall, causing a thinning of the vessel wall within this region of the vessel making it more susceptible to failure. In addition to this, digital image correlation (DIC), a full field strain measurement technique, was used to gain an insight into the changes occurring within the tissue during the sealing process and provide validation for the FEM. The result of the DIC analysis showed strains of a similar magnitude to those produced within the FEM and also highlighted regions of strain concentration in similar positions to those calculated by the FEM thus validating the modelling technique. The study presents a method for modelling vessel compression and the surgical sealing process, with the techniques used being validated through the use of DIC. The FEM provided an insight into why predominantly elastic vessels fail at a lower burst pressure when compared to more muscular vessels, and demonstrated the capabilities of using FEM in investigating surgical procedures.