A micro ultrasonic scalpel with sensing function

A micro ultrasonic scalpel based on a piezoelectric film transducer can cut very soft and small objects with slight deformation and monitor the vibration condition during operation. The micro ultrasonic scalpel has longitudinal vibration component and also lateral vibration component for effective cutting performance. The coupled vibration mode was effectively generated by a micro-notch at the largest stress part of an exponential horn in the longitudinal mode from the result of the finite element method(FEM). Cutting performance with the coupled vibration mode was tried out by sticking the micro ultrasonic scalpel into bovine liver, while it was vibrating or not. When the micro ultrasonic scalpel was vibrating, it could be stuck smoothly. But when it wasn´t vibrating, it was stuck with rapid deformation on bovine liver´s surface. So cutting performance was denoted. From the result of the FEM, we also realized that the ratio of the vibration velocity in lateral direction to that in longitudinal direction was about 0.6. It is expected that the micro ultrasonic scalpel will be built into surgical tool in an endoscope.