Active load control of ultrasonic surgical instruments

An ultrasonic system for use in surgical procedures comprising:

• an ultrasonic signal generator, wherein said ultrasonic signal generator produces an electrical signal at an ultrasonic frequency, said electrical signal having a load parameter indicative of generator load;
• a transducer electrically connected to said generator, wherein said transducer is adapted to convert electrical energy from said ultrasonic signal generator into mechanical motion;
• an ultrasonic surgical instrument comprising:
• a handle assembly, wherein said handle assembly is operatively coupled to said transducer;
• a waveguide acoustically coupled to said transducer, wherein said waveguide is adapted to transmit ultrasonic energy therethrough;
• an end-effector located at the distal end of said waveguide;
• an actuation element, wherein said actuation element is operatively coupled to said end-effector;
• and
• a force responsive element electrically connected to said ultrasonic signal generator and operatively coupled to said actuation element, wherein said force responsive element is adapted to alter a force on said actuation element in response to said electrical signal from said ultrasonic signal generator.

A system for use in surgical procedures comprising:

• a generator, wherein said generator comprises a signal means for indicating generator load;
• a surgical instrument electrically connected to said generator, said surgical instrument comprising:
• an actuating means for actuating an end-effector means of said surgical instrument;
• wherein the end-effector means is engageable with tissue;
• and
• a force means operatively coupled to said actuating means and said end-effector means, for altering a force on said end-effector means in response to said signal means.

A method of modifying the force exerted by an electrosurgical instrument on tissue, said method comprising the steps of:

• a) clamping said tissue with an end-effector of the electrosurgical instrument;
• b) applying energy to said tissue through said surgical instrument;
• c) sensing the tissue load on the surgical instrument;
• d) providing an electrical feedback signal to the surgical instrument, the feedback signal having at least one component representative of the tissue load;
• and
• e) modifying the clamping force applied by the end-effector on the tissue in response to the electrical feedback signal.