Design of Miniature Ultrasonic Surgical Devices

Orthopaedic surgery involves cutting through bone and the removal of bone, bone spurs or ligament. Ultrasonic surgical devices, employing an ultrasonically excited cutting blade, have demonstrated precision and accuracy in bone surgeries, allowing surgeons to carry out bone cutting in difficult-to-reach surgical sites. For surgical procedures in a confined space, a small surgical device has benefits, but for ultrasonic devices this results in a reduced amount of piezoceramic material in the transducer. This paper provides insights into the trade-offs between the volume of piezoceramic material, location of the piezoceramic rings, resonant frequency and the achievable vibration amplitude. Bolted Langevin-style Transducers (BLT) are adopted for this study. Experimental results show that a similar level of vibration displacement can be achieved at a much lower input voltage with a higher quantity of piezoceramic elements. However, the associated nonlinear behaviour is exacerbated. Locating the piezoceramic elements at the longitudinal displacement node is critical, in order to maximise the ultrasonic energy transfer