Vessel sealing system

A system for electrosurgically sealing tissue, comprising an electrosurgical generator comprising an RF energy source and a controller for controlling the operation of the electrosurgical generator, said electrosurgical generator having an output for coupling to a surgical instrument comprising electrodes for coupling RF energy generated by said electrosurgical generator to tissue to be sealed;

• said controller being operable for causing said electrosurgical generator to apply an initial pulse of RF energy to the tissue and for measuring a value of an electrical characteristic of the tissue in response to the applied initial pulse, said controller being responsive to the measured electrical characteristic for determining an initial set of pulse parameters for a subsequent pulse and for then varying the pulse parameters of individual pulses of further subsequent RF energy pulses in accordance with a change in the electrical characteristic;
• said system further comprising an operator-actuated seal intensity control, wherein said controller is coupled to an output of said seal intensity control and is responsive thereto, when determining said initial set of pulse parameters, for modifying predetermined ones of said initial set of pulse parameters.

A system for electrosurgically sealing tissue, comprising an electrosurgical generator comprising an RF energy source and a controller for controlling the operation of an electrosurgical generator, said electrosurgical generator having an output for coupling to a surgical instrument comprising electrodes for coupling RF energy generated by said electrosurgical generator to tissue to be sealed;

• said controller being operable for causing said electrosurgical generator to apply an initial pulse of RF energy to the tissue and for measuring a value of an electrical characteristic of the tissue in response to the applied initial pulse, said controller being responsive to the measured electrical characteristic for determining an initial set of pulse parameters for a subsequent pulse and for then varying the pulse parameters of individual pulses of further subsequent RF energy pulses in accordance with a change in the electrical characteristic of the tissue.

A method for electrosurgically sealing tissue, comprising steps of:

• applying a first pulse of RF energy to the tissue;
• and
• applying at least one subsequent RF energy pulse to the tissue and varying RF energy parameters of individual pulses of subsequent RF energy pulses in accordance with at least one characteristic of an electrical transient that occurs at the beginning of individual pulses of the subsequent RF energy pulses.

A method for electrosurgically sealing tissue, comprising steps of:

• applying a first pulse of RF energy to the tissue, the tissue being held between opposing jaws of a surgical instrument;
• and
• applying a plurality of subsequent RF energy pulses to the tissue while controllably decreasing an amplitude of individual ones of the subsequent RF energy pulses, the amplitude being controllably decreased in order to compensate for a decrease in distance between the opposing jaws due to a thermally-induced shrinkage of the tissue.

A system for electrosurgically sealing tissue, comprising an electrosurgical generator comprising an RF energy source and a controller for controlling the operation of electrosurgical generator, said electrosurgical generator having an output for coupling to a surgical instrument comprising electrodes for coupling RF energy generated by said electrosurgical generator to tissue to be sealed;

• said controller being operable for causing said electrosurgical generator to apply an initial pulse of RF energy to the tissue that is adapted to be between opposing jaws of the surgical instrument, and for applying a plurality of subsequent RF energy pulses to the tissue while controllably decreasing an amplitude of individual pulses of the subsequent RF energy pulses, said controller controllably decreasing amplitude in order to compensate for a decrease in distance between the opposing jaws due to a thermally-induced shrinkage of the tissue.