Study on driving and detection of micro-knife for minimally invasive surgery

In this paper we studied the micro-knife for minimally invasive surgery and its driving device which is the PZT-4 plates. It works in an ultrasonic vibration mode to realize the precise incision with its sharp tip at one end. We estimated the micro-knife´s resonant frequency in longitudinal direction and transverse direction. After the resonance and anti-resonance frequency of the PZT-4 plates were obtained, we chose the PZT-4 plates whose resonant frequency is close to the natural frequency of the Micro-knife and used them to excite the micro-knife into vibration. We mainly study three kinds of the micro-knife which are symmetrical linear, partially unsymmetrical exponential and totally unsymmetrical exponential. The entire micro-knives´ vibration was observed and measured by using the high-power digital microscope and CCD equipment in the precision optical platform. The result measured suggests that the micro-knife in an unsymmetrical shape is more suitable for cutting.