Potential use of polydimethylsiloxane phantom in acupuncture manipulation practice

Abstract

Objectives: Sufficient trials of acupuncture manipulations should be practiced to obtain proficiency. However, there is not an adequate quantitative methodology for selecting a tissue-mimicking phantom that effectively reproduces the mechanical behavior that occurs during acupuncture. The objective of this study was to determine the proper mixing ratio of polydimethylsiloxane (PDMS) to obtain tissue phantom that is the most similar to porcine phantoms. Design: An automatic needle manipulator equipped with a six-degrees-of-freedom force/torque sensor was installed to monitor the interaction force that occurred when the acupuncture needle performed lifting–thrusting and twirling manipulations. Four types of PDMS phantoms, composed of two silicone elastomers with different hardener ratios, were studied alongside four control groups consisting of different porcine sites. A Visual Analog Scale was used to quantify the similarity of the PDMS phantoms to the controls by 11 Korean medical doctors. Results: Using the lifting–thrusting method, PDMS D (mixing ratio of 1:4.5) and control 2 (porcine blade shoulder) revealed no significant difference in the dynamic friction coefficients or maximum and minimum friction force values (P < 0.001). Using the twirling method, PDMS D showed no significant difference from all controls in the viscosity coefficient or maximum and minimum torque values (P ≤ 0.001). By practitioners, PDMS D showed the greatest score. Conclusion: PDMS D delivered a haptic sensation that is most similar to that of biological tissues in the case of acu-needle lifting–thrusting and twirling methods. This finding guides the preparation of tissue phantoms for acu-needle studies and acupuncture training.

Keywords

• Acupuncture needle
• Friction force
• Karnopp friction
• Tissue-mimicking phantom
• Acupuncture manipulation