Ultrasonic surgical devices driven by piezoelectric tubes

Minimally invasive surgery can potentially benefit from the use of ultrasonic devices through their high precision, low force, and tissue selectivity, thus reducing morbidity, recovery time and cost. To facilitate this, miniature ultrasonic surgical tools are required, integrated with flexible surgical robots to guide them to surgical sites inside the body. This paper presents two novel designs of miniature ultrasonic surgical devices excited by a radially polarized piezoelectric tube. One configuration employs the longitudinal mode of the tube and the other uses the breathing mode in a flextensional configuration, to achieve a longitudinal motion of the blade. Experimental results show that the vibration at the tip of the blade of the cymbal end-cap (flextensional configuration) has developed a 4-6 times higher amplitude with the same excitation than the stepped horn (longitudinal configuration), demonstrating potential for using the breathing mode of the piezoelectric tube.