A method is disclosed comprising: introducing a treatment member into a living body and positioning the treatment member adjacent substance in the living body to be ground moving the treatment member in at least a clockwise direction or a counterclockwise direction about a central axis, which is different from an axis of rotation of the treatment member while the treatment member is positioned adjacent the substance to be ground in the living body to grind the substance and shearing debris resulting from the grinding of the substance to reduce a size of the debris.
