Objective To calibrate contact parameters of liver tissue discrete element model. Methods Based on MATLAB image processing technology, the accumulation angle of liver tissues was measured. The ‘Hertz-Mindlin with JKR’ contact model was used to simulate the accumulation angle of liver tissues. The orthogonal experiment was designed with the coefficient of rolling friction and the energy of JKR surface as factors. The parameters of the contact model were calibrated by batch processing, and the optimal parameter combination was verified by secondary simulation calibration. Results The accumulation angle obtained by the physical test was 11.2°±0.86°. In the orthogonal experiment, the accumulation angle of the 6th set of parameter combinations was 11.8°, and the relative error was 5.1%. The simulation test and the physical test had a high similarity in accumulation angle and shape. The sequence of factors affecting the accumulation angle was the JKR surface energy between the tissue particles and the stainless steel plate > the rolling friction coefficient between the tissue particles and the stainless steel plate > the JKR surface energy between the tissue particles and the tissue particles=the rolling friction coefficient between the tissue particles and the tissue particles. Conclusions The optimization parameter could be used to further conduct the discrete element simulation between the tissue particles and the pulverizer, so as to reveal the accumulation and flow state of the tissue particles under the action of myoma pulverizer.

With the development of minimally invasive surgery, many open surgery has been replaced by intracavity surgery. In laparoscopic surgery, an electric fibroid morcellator must be used to remove large tissue specimens from a small abdominal incision. Of course, there are some complications in the use, in order to follow the principle of no tumor, the doctor used the laparoscopic pouch in clinical operation to reduce the risk of spreading potential tumor tissue. There are various kinds of pouches, which are classified according to their existing state before use, it can be classified into two categories:overlapping and non-overlapping. The advantages and disadvantages of different bags and pockets are also analyzed. It provides a theoretical basis for technological innovation and equipment improvement.
Laparoscopy ; instrumentation ; Minimally Invasive Surgical Procedures