Unintended stray energy from monopolar instruments: beware the dispersive electrode cord

Background The monopolar instrument emits stray radiofrequency energy from its cord when activated. This is a source of unintended thermal injury to patients. Stray energy emitted from the dispersive electrode cord has not been studied. The purpose of this study was to determine whether, and to what extent, the dispersive electrode cord contributes to unintentional energy transfer and describe practical steps to minimize risk. Methods In a laparoscopic simulator, a monopolar generator delivered radiofrequency energy to an L-hook. Thermal imaging quantified the change in tissue temperature nearest to the tip of a non-electrical instrument following activation. The orientation of the dispersive electrode cord was varied relative to other instruments. Results When the dispersive electrode cord is parallel to the camera cord, tissue temperature increased at the telescope tip by 46 ± 6 °C from baseline ( p