Electrovaporization of Prostate at Power Settings Below 100 W

Abstract

Background and Purpose: Prostate electrovaporization has usually been performed at high power settings in the pure cut mode, using traditional electrosurgical generators. However, this practice is empirically based on the fact that a vaporization electrode is larger than a cutting wire loop. The role of the electrosurgical unit (ESU) in prostate electrovaporization has not been studied in detail.Methods: In this Phase II cohort comparison study, we evaluated two different ESUs, coupled to the most clinically efficient vaporization roller electrode available in our opinion, to determine the lowest panel power settings that permit consistent tissue removal despite the desiccation normally produced during electrovaporization. Results: One of these ESUs, the Excalibur Plus^®, permitted prostate electrovaporization at panel settings below 100 W for the first time, without compromising satisfactory early clinical outcomes. In a small number of cases, the spiked VaporTrode-Force 2 combination permitted effective electrovaporization at a lower power setting (180 W) than has previously been described when this ESU was coupled with the grooved VaporTrode, regardless of prostate size. During bench tests, a comparison of the actual power output curves in the clinically effective panel power setting range for each ESU revealed that the Force 2 overestimated the actual power output as impedance increased, while the Excalibur Plus underestimated it. This difference may explain why tissue could be vaporized at such low panel settings without the use of computer-controlled technology. Conclusion: These findings indicate a potential for improving the safety and efficiency of tissue clearance during prostate electrovaporization through future modifications in monopolar electrode design coupled with use of a generator that can either maintain or slowly increase actual power output as impedance increases at low panel settings. A Phase III clinical study would be justified on the basis of our preliminary results.