Optimal mode and power output of electrosurgical units for endoscopic papillectomy based on animal experiments and a preliminary clinical study (with videos).

Background And Aims: The optimal electrosurgical unit (ESU) settings for endoscopic papillectomy (EP) have not been investigated. We conducted animal experiments to determine the optimal endoCUT settings with VIO (Erbe, Tübingen, Germany) ESUs and then conducted a small clinical study.

Methods: Dedicated animal experimental models were created. To investigate the incision force, chicken meat was resected with a snare whose handle was a hung weight. To investigate the coagulation effect, a surgical needle electrode was inserted into a pig liver and energized, and to determine changes over time in the coagulation status, simulated EP was performed using a living pig. These experiments were performed using the knife-setting or snare-setting endoCUT modes and various effect, duration, and interval settings and compared with results for ICC (Erbe) ESUs. Based on the results, we performed EP in a small number of patients.

Results: The main factor affecting the incision force was duration. The coagulation effect was related to not only effect but also duration. In the endoCUT mode, knife-setting produced a higher incision force and lower coagulation effect. The nondischarge coagulation effect may cause deep ulceration. Based on the animal experiments, we concluded the ideal ESU setting for EP, "VIO EP mode," is knife-setting with high duration, lowest effect, and low interval settings. In the clinical study, there were no significant adverse events such as bleeding, pancreatitis, or perforation.

Conclusions: "VIO EP mode" seems to afford optimal papillectomy. Larger scale clinical studies are needed to accumulate further data and make clinical comparisons with the ICC ESU.