I'll avoid making this post too technical and boring. Simply speaking, piezosurgery is a technique which first came out of Europe (Italy), and utilizes ultrasonic energy to manipulate bones. The technique is completely atraumatic to soft tissue (skin, fat, muscle, cartilage), and will selectively manipulate only bone. Thus, piezosurgery techniques are directed toward the upper third of the nose, which is mostly bone (ie, humps, bumps, crookedness).
 

An insert into Dr. Sparano's Rhinoplasty NJ series:
 

Part of what makes rhinoplasty such a tremendously interesting surgical procedure, is that there exists an interrelated geometry and physics among the various structures of the nose. That is, no isolated anatomic structure can be assessed, or certainly manipulated, without consideration of other anatomic structures. Each anatomic element of the nose exists in relation to the others, and maintaining a balance among the elements is the beautiful symphony that is rhinoplasty.