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.