Patent ID: 8308721

Claim:
A surgical system comprising: a treatment member that treats living body tissue targeted for treatment by applying an ultrasound vibration and a radio-frequency electrical current to the living body tissue, the treatment member provided at a distal end portion of an elongated probe; an ultrasound transducer that generates the ultrasound vibration under application of an ultrasound drive signal, the ultrasound transducer transmitting the generated ultrasound vibration to the treatment member via the probe; an ultrasound drive signal generator that generates the ultrasound drive signal to be applied to the ultrasound transducer; a radio-frequency wave generator that generates a radio-frequency output signal having an output wave-form defined by a base frequency and a repetition frequency so as to supply the radio-frequency output signal to the treatment member via the probe; a detecting circuit including a voltage detecting circuit that detects a voltage of the radio-frequency output signal applied to the living body tissue via the treatment member and an electric current detecting circuit that detects an electric current flowing through the living body tissue; an electric impedance detecting circuit that detects and electric impedance value which the living body tissue has based on the voltage and the electric current detected by the detecting circuit; a memory that stores a threshold value set for judging whether or not the living tissue has an electric impedance value within a range in a case where the living body tissue is fatty tissue; a judging circuit that judges whether or not the living body tissue includes a component corresponding to the fatty tissue by comparison of the electric impedance of the living tissue targeted for treatment detected by the detecting circuit, and the threshold value stored in the memory; a peak value detecting circuit that detects a voltage peak value of the radio-frequency output signal detected by the voltage detecting circuit; and a controller that controls the peak value of the radio-frequency output signal detected by the peak value detecting circuit not to exceed a predetermined value, if it is judged by the judging circuit that the electric impedance value detected by the electric impedance detecting circuit when the ultrasound vibration from the ultrasound transducer to the treatment member and the radio-frequency output signal from the radio-frequency wave generator to the treatment member are simultaneously supplied is an electric impedance within the range between an upper-limit threshold value and a lower-limit threshold value as the threshold value stored in the memory to be corresponding to the fatty tissue.