Vascular tissue sealing pressure control

A clamping force mechanism for an instrument for allowing a user to clamp and apply force and electrosurgical energy to seal and/or join particular vascular tissue of a patient comprising:

• an elongate support having a user end and a patient end;
• an actuator at the user end for operation by the user;
• a pair of end effectors at the patient end, the pair of end effectors connected to the actuator for operation thereby and from the user end to control motion of the pair of end effectors, the pair of end effectors each having an opposing face of an area adapted for contact with particular vascular tissue of the patient;
• a lost motion connection between the pair of end effectors at the patient end and the actuator at the user end, the lost motion connection for transferring user manipulation of the actuator to the pair of end effectors for maintaining force over the opposing face of an area to achieve a predetermined clamping force application during sealing of particular vascular tissue of the patient between the pair of end effectors;
• a yielding member in the lost motion connection so the opposing faces clamp particular vascular tissue of the patient therebetween with the predetermined clamping force from the yielding member, the yielding member including a spring as part of the lost motion connection between the pair of end effectors at the patient end and the actuator at the user end, the spring located near the actuator at the user end to maintain a predetermined clamping force within an preferred range irrespective of total user manipulation;
• an elongated transfer rod in the lost motion connection, the elongate transfer rod located between the spring near the actuator and the pair of end effectors at the patient end, the rod coupled to the pair of end effectors for movement thereof between an open position adapted to receive particular vascular tissue of the patient to a clamping position adapted to maintain the predetermined clamping force on particular vascular tissue of the patient between the pair of end effectors;
• an active electrode carried on one of the pair of end effectors;
• a return electrode in contact with the tissue of the patient;
• an electrosurgical energy supply connected across the active electrode of the pair of end effectors and the return electrode to provide an electrosurgical circuit therebetween, the electrosurgical energy supply for delivery of electrosurgical energy between and across the active electrode and the return electrode when particular vascular tissue of the patient is held by the pair of end effectors;
• an electrosurgical generator in the electrosurgical energy supply to provide electrosurgical energy;
• a feedback circuit in the electrosurgical generator, the feedback circuit electrically coupled in circuit with the active electrode and the return electrode, the feedback circuit responsive to energy delivery through the electrosurgical circuit of particular vascular tissue of the patient interposed between the active electrode and the return electrode;
• a temperature sensor in the feedback circuit, the temperature sensor carried on at least one of the opposed faces, the temperature sensor responding to temperature of particular vascular tissue of the patient between the pair of end effectors during delivery of electrosurgical energy;
• an impedance monitor in the feedback circuit, the impedance monitor electrically hooked up to the electrosurgical generator, an impedance circuit responsive to impedance of particular vascular tissue of the patient between the active electrode and return electrode during delivery of electrosurgical energy, and a control associated with the electrosurgical energy supply adapted to apply electrosurgical energy to the particular vascular tissue of the patient that is held in response to the predetermined clamping force application for sealing particular vascular tissue between the pair of end effectors.