Miniaturised ultrasonic aspiration handpiece for increased applicability.

OBJECTIVE: At present, ultrasonic aspiration is routinely used in several fields of surgery, especially in brain and spinal micro-surgery for tumour removal. In order to broaden the access to difficult surgical sites, it is important to design highly miniaturised but still efficient handpieces. The internal resonant system, always made of high-grade materials, must be optimally dimensioned. Normally this is done semi-empirically, by successively improving the design during many iterative test steps. This method however involves several additional difficulties when the degree of miniaturisation increases. For example, small transducer weights exacerbate heat-dissipation problems and make design optimisation important.

METHODS: To resolve these problems we have produced modelling software that makes it possible to simulate and automatically tune each individual interacting section of the design before it is actually manufactured, thereby assuring optimal efficiency.

RESULTS: Using a new mini-handpiece, designed via the software, two cases of dissection of acoustic neurinomas were successfully performed.

CONCLUSION: Using conventional physical steps for improving ultrasonic aspiration handpieces, several problems arise when the grade of miniaturisation increases, due to increasing demands. We have designed computer software for handpiece simulation. Using this model it has been possible to manufacture a highly efficient miniaturised handpiece.