A Review of Capacitive Return Electrodes in Electrosurgery

Background: Monopolar electrosurgery, one of the most widely used techniques in surgery, requires two electrodes: a working electrode and a return electrode. Commonly, adhesive or “sticky” pads that attach directly to the patient are used as return electrodes. Acting as electrolytic conductors, adhesive pads are highly effective, but require some effort to apply and remove, and if improperly placed or partially detached may lead to high electrical current density and the potential for pad site burns. Alternatively, a capacitive return electrode, such as the Mega Soft pad, may be used that works on the same principle as a two-plate capacitor. Objective: This article details the technology underlying capacitive electrodes, reviews the scientific literature to-date, and provides recommendations on how to best use the Mega Soft pad. Results: No direct contact is required between the pad and patient, and the return electrode is designed so that current density is limited regardless of pad placement, reducing the risk of pad site burn. Although the technology is now mature, having been in the field for over 20 years, best practices for optimal performance from capacitive return electrodes are still not widespread, and misunderstandings persist regarding use of capacitive electrodes with contact monitoring systems and implantable electronic devices. Conclusion: With proper training, capacitive return electrodes may be substituted for conventional adhesive pads with the benefits of easier application and reduced risk of pad site burns.