An aspirating ultrasonic surgical device for the melting and removal of thermoplastic prosthetic implant cement is provided. The instrument defines a centrally located bore which expands in diameter from a surgical tip in the direction of aspirant flow for a length equal to at least 1/4 the wavelength corresponding to the resonant frequency of the device so as to prevent blockage by solidified cores of cement. Alternatively, the bore expands from a first uniform diameter extending from the tip end to a second uniform diameter. A compound taper at the tip end minimizes contact between the outer surface of the tube at the tip end. A novel transducer cooling system is provided by incorporating a thermally conductive, electrically insulating material between the piezoelectric crystal (which generates heat as a byproduct) and a hollow metal bolt which defines a central bore through which cooling irrigant flows to conductively remove heat generated by the crystal.