A surgical instrument having a handle, elongate shaft, end effector and an actuating mechanism to control the end effector. A drive shaft 316 extends between the end effector and actuator, having a distal aperture 1000, and an elongate slot to receive an inner component longitudinally slideable within the drive shaft. The end effector may be a pair of jaw members with electrodes, and the inner component may be a blade assembly. There may be drainage passages leading from the drive shaft apertures.
