Low power tissue sealing device and method

A power control system for delivering radio frequency energy to a vessel fusing surgical instrument including an end effector, the power control system comprising:

• a power supply for delivering an output voltage and an output current to the end effector;
• an impedance sensing circuit for detecting an impedance of a vessel being fused;
• a power sequencing module for automatically sequencing an electrosurgical power delivered to the surgical instrument;
• wherein the power sequencing module is adapted to:
• raise the output current of the power supply to between 0.5 and 1.75 Amperes RMS and the output voltage of the power supply to between 5 and 135 Volts RMS;
• apply non-pulsing power of no less than 7 Watts and no more than 35 Watts, between 0.5 and 1.75 Amperes RMS and between 5 and 135 Volts RMS to the vessel being fused for a period of time of 3 seconds or less, wherein the non-pulsing power causes the vessel to reach a temperature of at least 140 degrees Celsius, and the period of time is measured from the beginning of the application of the non-pulsing power and continues through the beginning of a desiccation of the vessel and through a drying out and the fusing of the vessel;
• monitor an impedance of the vessel being fused through the impedance sensing circuit during the period of time;
• limit the flow of power to the vessel being fused when the impedance of the vessel being fused reaches a set impedance threshold within the period of time;
• and
• terminate the flow of power to the vessel being fused when the impedance of the vessel being fused reaches a predetermined level.

A surgical system for fusing a passageway of a fluid-carrying vessel with a diameter up to 5 millimeters, the system comprising:

• an electrosurgical generator capable of delivering electrosurgical power;
• a surgical instrument electrically connected to the electrosurgical generator and adapted to transfer electrosurgical power from the electrosurgical generator to a pair of end effectors disposed at a distal end of the surgical instrument, wherein the end effectors are adapted to close the passageway of the vessel;
• and
• a power control circuit for controlling the delivery of radio frequency energy to the vessel through the end effectors;
• wherein the surgical system is configured to
• deliver a radio frequency energy to a vessel, the radio frequency energy having a non-pulsed power having an output current between 0.2 and 1.75 Amperes RMS and an output voltage between 5 and 135 Volts RMS;
• apply the non-pulsed power to the vessel for a period of time while the non-pulsed power is held at between 7 Watts and 35 Watts, while allowing the output current to fluctuate between 0.2 and 1.75 Amperes RMS and the output voltage to fluctuate between 5 and 135 Volts RMS, wherein the period of time is measured from the beginning of the application of the non-pulsed power and continues through fusing of the vessel, and the non-pulsed power causes the vessel to being to dessicate within the period of time, wherein the period of time is 3 seconds or less;
• and
• monitor an impedance of the vessel being fused;
• limit the flow of non-pulsed power when the impedance of the vessel being fused reaches a set impedance threshold;
• and
• terminate the flow of non-pulsed power when the impedance of the vessel being fused reaches a predetermined level indicative that the vessel being fused is desiccated.