Solving Biomechanical Challenges with Yamaguchi University

Posted on 19 January 2018 by Jessica James

Miki Miyazaki of our Japanese resellers JSOL recently conducted an interview with Simpleware users Yamaguchi University about their use of 3D modelling and simulation. The following interview provides some excellent insight into how our software is used in a medical setting alongside LS-DYNA simulation for analysing spinal pathologies and other issues. 

This interview with Doctor Norihiro Nishida, Professor Xian Chen, and Associate Professor Junji Ohgi, covers their experiences with medical engineering collaboration to date. You can see a more detailed example of their work in this case study on brachial plexus injuries.

Dr. and Assistant Professor Norihiro Nishida (right), Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Associate Professor Junji Ohgi (left), Professor Xian Chen, Department of Mechanical Engineering, Yamaguchi University (centre)

Dr. and Assistant Professor Norihiro Nishida (right), Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Associate Professor Junji Ohgi (left), Professor Xian Chen, Department of Mechanical Engineering, Yamaguchi University (centre)

Q01 You are working closely with the medical school and engineering departments at Yamaguchi University to promote medical collaboration. Can you describe the history of this relationship?

Associate Professor Ohgi: It was in about 2001 that medical collaboration began systematically in Yamaguchi University. We were one of the first universities to organize collaborations, starting with experiments on the spinal cord and simple two-dimensional software analysis.

Dr. Nishida: I entered the graduate school in 2010, and then started working on using the Finite Element Method (FEM). At that time, I was a clinician, and felt limited dealing with FEM software.

JSOL: Medical professors who work concurrently at a clinic have special challenges for gaining expertise in FEM, which meant starting the relationship between the Faculty of Engineering and the Faculty of Medicine.

Dr. Nishida: Yes, it was around 2014 that we increased collaboration. When I heard lectures at other universities, I thought that I would lag behind if I didn’t work with experts at the Faculty of Engineering.

Associate Professor Ohgi: In the past, there were teachers who were developing and analyzing their own programs at university. I was doing two-dimensional analysis of spinal cord experiments and spinal cord compression, but now that Dr. Nishida has joined, I am doing 3D analysis.

Q02 What kind of hurdles were involved in advancing medical cooperation?

Associate Professor Junji Ohgi: “We started collaborations between medicine and engineering in 2001 through experiments on the spinal code and 2-dimensional software analysis”

Professor Chen: “Medical and engineering department’s purpose was the same so we could discuss and get over any hurdles”

Professor Chen: One challenge is finding a common way of communicating between medical and engineering departments: in engineering, the model refers to shapes and parts, but in the medical department, it usually means symptoms and treatment of diseases such as diabetes and cancer. Also, we have different ways of thinking and planning our research schedules. In engineering departments, it is normal for us to perform the tasks which are piled up one by one. On the other hand, in the medical department, they need to identify the disease and think about curing the sickness first. After we received the simulation results, we as engineering teachers thought we could make a first step to solve the massive problems. Medical teachers, however, have to make it a top priority to cure diseases and produce results as soon as possible.  I can say it is a cultural difference we have. They also have to learn advanced engineering knowledge such as calculating reaction forces, stress and strain, which is very difficult.

JSOL: How about the Faculty of Medicine?

Dr. Nishida: I am grateful that the engineering people have created an elaborate three-dimensional model on the engineering department side. However, if you show that model to other doctors in the Faculty of Medicine, you may be told that "This shape is anatomically funny". When I was doing the Finite Element Method by myself, I learned the difficulty and limitations of assembling a model from scratch, so I think that it is my role to compensate for the gap between the two departments.

Q03 Please tell us about your future research contents and goals.

Associate Professor Junji Ohgi: “We started collaborations between medicine and engineering in 2001 through experiments on the spinal code and 2-dimensional software analysis”

Associate Professor Junji Ohgi: “We started collaborations between medicine and engineering in 2001 through experiments on the spinal code and 2-dimensional software analysis” 

Professor Chen: I believe it is important to define concrete goals between the medical and engineering departments. For example, Mr. Nishida makes a musculoskeletal model as a unique Yamaguchi University model, and that is consistent with both the goals of the Faculty of Engineering and other departments, and gives me confidence to move forward while dealing with whatever hurdles come up.

JSOL: It is wonderful to have the same goal and to promote efforts towards interdepartmental collaboration. Can you tell us about your work on the material properties of human tissue and how the FEM model is created?

Associate Professor Ohgi: Yes. Originally, I was researching industrial materials such as metallic materials and ceramics, and started experimenting in medical science for eight years ago. Once the metal material is identified, material physical properties can be obtained by two or three tensile tests, but the medical field is difficult to handle and it varies considerably, even with one specimen. The reason for this variation is that different factors, such as age, are taken into consideration, and the physical properties for FEM are complex.

JSOL: Are the physical properties largely different according to age?

Associate Professor Ohgi: Currently we are working on experiments in a yellow ligament which was removed during surgery. We have performed a large number of experiments and the results of significant testing showed there was a difference in age, so during our research we came to see a distinctive difference of the physical properties by age. I think it is necessary to do more research on various body parts, perhaps not only on a ligament or spinal cord.

JSOL: Do you have any plans to investigate to the whole body?

Dr. Nishida: For example, when we perform an operation on patients over the age of 80, it doesn’t always bring the better outcome compared to younger ones. In cases where we do the same surgery on other elderly people and the patients whose illness is not advanced, the result was the same. So it is said that aging is the reason for that. I know there are some researchers who study a cell and at tissue level, but I guess there are few people who do research on the physical properties. To create a working human body model, I think that it will not match the experimental data unless you create a model for each age group.

So far after surgery we used to dispose the body parts which were no longer necessary. We have thought we could utilize it for research so I asked the associate Prof. Ohgi of the engineering department, and he told me that he would try. I usually provide dry sample to him so I feel sorry about it, but we are strictly prohibited from changing the operation method for our study. Therefore I contact him about the operation date and the possible body parts which can be collected during the surgery; the experiment would then be carried out in the engineering department.  At the moment, Professor Chen has made an FEM model of the skeleton, and I think we need to make models of various parts that will help our clinical work. I happened to use FEM by myself, so I was able to take advantage of my experience and collect the necessary tissues and cells in some experiments on spinal cord. I would like to expand our experience to the other organizations and involve professors from different departments, and to create all orthopedic parts.

Q04 Please tell us about the future prospects for medical cooperation collaboration.

Dr. Norihiro Nishida: “We need to develop models suitable for clinical use” 

Dr. Nishida: I would eventually like to create a ‘Yamaguchi University human body model’ which is approximate to a human body. It would allow us to tell how much metal is fixed during surgery for each type of skeleton and before the surgery: we could say “It is safe for this patient to fix the metal and pressurize to some extent”, or “It will be risky if we continue more.” If you can use computer simulation before surgery, you will be able to minimize risk. By making a model, you will also be able to tailor products to the skeleton, such as nursing care products, daily necessities, screws, and beds. This is the final goal for me.

JSOL: Do you plan to advise implant or medical device makers or design medical devices by Yamaguchi University's skeletal model?

Dr. Nishida: It may be good if we can simulate with various skeleton models. To medical device manufacturers, I show the model we created at Yamaguchi University and ask if they can use the model to analyse their screw placements. That would be great if it came true.

Q05 Can you explain how you work with JSOL?

Associate Professor Ohgi: Our students are very much indebted to training on Simpleware and simulation tools, and advice on how to use it. I would like to eventually model the whole human body, as Dr. Nishida mentioned earlier, so it would be excellent if you can automate as much as possible on the software side.

Professor Chen: Medical scientists and engineers look at data together and operate some simulation software, and if we could find out illness in real time, then that would be practical. For that, we will develop various methods. However, something like interfaces, image processing, and high-speed solver are areas that we can’t do, but JSOL can because JSOL is an analysis specialist. We expect JSOL to play a big role when we need the support of the software.

 

Thanks to:
Norihiro Nishida, Junji Ohgi, Xian Chen

Official website: http://www.yamaguchi-u.ac.jp
Read more on: Analyzing Brachial Plexus Injury using FEM
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