Sonic burr

An ablative burr (100) that may be used for a medical procedure, such as an atherectomy, that does not require the user of an elongate flexible drive shaft. The burr comprises a main body (110) that is elastically connected to an abrasive shell member (130). One or more oscillatory driver(s) (150), such as a piezoelectric transducer, is disposed between the shell member and the main body to oscillate the shell with respect to the main body. Elastically compressible members (140, 142) are provided between the shell member and the main body member. The oscillatory drivers are preferably set or tuned to operate at a resonant frequency of the shell member whereby shell member amplitudes larger than the oscillatory driver amplitudes may be induced. Embodiments of longitudinally oscillatory burrs (100, 200) and rotationally oscillatory burrs (300, 400) are disclosed.