A surgical instrument includes an elongated shaft, with components arranged in the shaft. The elongated shaft is slightly curved. Arranged on a proximal end of the surgical instrument is an actuation device in the form of a lever mechanism and rotary knob. A force transmission element in the form of a plastic hollow section is arranged in the shaft. The force transmission element is a plastic section designed for transmitting compressive and tensile forces. The plastic section is provided with a plurality of longitudinally extending channels. Therefore, the plastic section does not only serve as a force transmission element, but electric lines and a pull-push shaft may additionally extend in the channels. The longitudinal channels may be used for supplying cooling media for the electrodes or the thermo-fusion device or for feeding agents promoting wound repair. The plastic section is electrically insulating, so that the risk of short-circuits is reduced.
