Patent ID: 8372070

Claim:
A surgical system comprising: a surgical instrument including a conducting section transmitting ultrasound vibration generated by an ultrasound transducer to a distal end portion that functions as a treatment section and transmitting a high-frequency output signal to the distal end portion; an ultrasound drive section outputting an ultrasound drive signal for driving the ultrasound transducer; a high-frequency output section outputting a high-frequency output signal to the conducting section; a detection section detecting an ultrasound impedance corresponding to an ultrasound drive state of the distal end portion in a state in which ultrasound energy is provided from the distal end portion to a site of surgery; a determination section determining whether the ultrasound impedance value detected by the detection section is within a predetermined range; an information storage section having a lookup table storing an increment or a decrement of a predetermined high-frequency output value based on the ultrasound impedance value detected by the detection section; and a control section performing control to maintain the high-frequency output value when the determination section determines that the ultrasound impedance value is within the predetermined range, reading out the increment or the decrement corresponding to the ultrasound impedance value from the lookup table when the determination section determines that the ultrasound impedance value is out of the predetermined range, and performing control to increase the high-frequency output value by the corresponding increment when the determination section determines that the ultrasound impedance value is greater than an upper limit of the predetermined range, and performing control to decrease the high-frequency output value by the corresponding decrement when the determination section determines that the ultrasound impedance value is less than a lower limit of the predetermined range.