An oscillating surgical cutting instrument includes a housing, a blade with at least a portion positioned distally of the housing, a transducer at least partially disposed within the housing, and a waveguide interconnecting the transducer and the blade. The transducer, waveguide, and blade are configured such that mechanical vibration energy produced by the transducer oscillates the blade at a frequency or within a frequency range from about 20 Hz to about 20 KHz to facilitate tissue dissection while minimizing thermal effects on tissue. A method of mechanical tissue dissection includes oscillating a blade at a frequency or within a frequency range from about 20 Hz to about 20 KHz and urging a tissue-contacting surface of the blade into contact with tissue to mechanically dissect tissue while minimizing thermal effects on tissue.