Research on analytical models for reducing friction heat for flexible ultrasonic propagation using stranded wire

The flexible ultrasonic scalpels are currently required for surgical treatment of deep-seated areas of the living body. One of the surgical treatments for early-stage gastric cancer is surgery to remove the superficial layers of the stomach. Endoscopic surgery is used for early-stage gastric cancer. Polypectomy, one of the endoscopic surgical methods, involves hooking a snare over the affected area, squeezing, and applying a high-frequency electric current to burn it off. On the other hand, ultrasonic scalpels are effective at lower temperatures than conventionally used electrocautery scalpels, and have the advantage of having less thermal effect on tissues other than the affected area. However, due to the challenges associated with the propagation of ultrasonic waves, the use of flexible wires for this purpose in current research is limited. In this study, we attempted to observe the characteristics of ultrasonic wave propagation to the wire in the snare, which is a part of the electrocautery used in the polypectomy. The development of flexible ultrasonic scalpels will be advanced when ultrasonic propagation with less energy loss to the strand wire can be realized. In addition, Finite Element Method analysis was performed to identify the heat sources generated when ultrasonic vibration is applied to a stranded wire and to investigate a solution. Additionally, to find conditions where ultrasonic energy propagation is strong and heat generation is minimal, the partial single lines model was examined. The analysis confirmed that heat was generated by friction between strands of stranded wire.