Objectives: Ultrasonically activated scalpel (UAS) is a surgical device utilizing ultrasonic energy to cut and coagulate tissues simultaneously. It is concerned that UAS may give damage to the tissues of different position from a designed treatment part by bioeffect of ultrasound. We verified the relationship of the vibration characteristics and bioeffect of UAS by multiple observation methods.
Methods: The laser Doppler vibrometer is used for the confirmation of the vibration distribution of some types of blades of UAS. Then, the observation experiment about generating of cavitations was conducted in the water tank. Additionally, the change of temperature distribution on the mesenterium tissue around the blade during activation was observed by an infrared thermography.
Results: The generating direction of cavitations and the vibration distribution was in agreement in every blade. The emergence rate of bubble and sound pressure distribution were also in agreement. The cavitations occurred besides the part for medical treatment in the grasp type blade. The coagulated range of the mesentery was spread according to the time of activation, and the form of the coagulated part was approximately in agreement with vibration distribution of each blade.
Conclusions: The direction of the generating of cavitations and the thermal diffusion were about in agreement with designed vibration of each blade. Although the tissue damage by cavitations was not confirmed in these case, it is required the consideration of the influence by the mixture situation of some tissues in grasped area and the angle between the blade and tissue.