A temperature or impedance sensing device monitors the tissue temperature or impedance at the end-effector of a therapeutic ultrasonic cutting and coagulating instrument as the tissue is being heated with ultrasonic vibrations from the end-effector. One or more sensors are located at the end-effector,...http://www.google.de/patents/US6454781?utm_source=gb-gplus-sharePatent US6454781 - Feedback control in an ultrasonic surgical instrument for improved tissue effects
