D. M. Overbey1,2, S. A. Hilton1, N. T. Townsend1, B. C. Chapman1, C. D. Raeburn1,2, T. N. Robinson1,2, E. L. Jones1,2 1University Of Colorado,Surgery,Aurora, CO, USA 2Denver Veterans Affairs Hospital,Surgery,Denver, CO, USA
Introduction: Energy-based devices are used in nearly every laparoscopic operation. Radiofrequency energy can transfer to nearby instruments via antenna and capacitive coupling without direct contact. Previous studies have described inadvertant energy transfer through bundled cords and nonelectrically active wires. The purpose of this study is to describe a new mechanism of stray energy transfer from the monopolar instrument through the operating surgeon to the laparoscopic telescope, and propose practical measures to decrease the risk of injury.
Methods: Radiofrequency energy was delivered to a laparoscopic L-hook (monopolar “bovie”), an advanced bipolar device, and an ultrasonic device in a laparoscopic simulator. The tip of a 10mm telescope was placed adjacent but not touching bovine liver in a standard four-port laparoscopic cholecystectomy setup. Thermal injury was measured as increased tissue temperature from baseline nearest the tip of the telescope which was never in contact with the energy-based device after a five second activation.
Results: The monopolar L-hook increased tissue temperature adjacent to the camera/telescope tip by 47±8°C from baseline (p<0.001). By having an assistant surgeon hold the camera/telescope (rather than one surgeon holding both the active electrode and the camera/telescope), temperature change was reduced to 26±7°C (p<0.001). Alternative energy devices significantly reduced temperature change in comparison to the monopolar instrument (47±8°C) for both the advanced bipolar (1.2 ±0.5 °C; p<0.001) and ultrasonic (0.6 ±0.3 °C; p<0.001) devices.
Conclusion: Stray energy transfers from the monopolar “bovie” instrument through the operating surgeon to standard electrically inactive laparoscopic instruments. Hand-to-Hand coupling describes a new form of capacitive coupling where the surgeon’s body acts as an electrical conductor to transmit energy (Figure 1). Strategies to reduce stray energy transfer include avoiding the same surgeon holding the active electrode and laparoscopic camera, or using alternative energy devices.
