A surgical instrument, such as an endoscopic or laparoscopic instrument, includes an ablation device. The ablation device includes an elongate member comprising first and second channels. First and second probes are disposed within the respective first and second channels, where the first and second probes each define a central axis. First and second electrodes are coupled to distal ends of the respective first and second probes. A distance between the first and second electrodes is adjustable by rotating at least one of the first and second probes about the central axis of the at least one of the first and second probes.