Ultrasonic, Bipolar, and Integrated Energy Devices: Comparing Heat Spread in Collateral Tissues

Abstract Introduction Integrated devices incorporating ultrasonic and bipolar technology have been utilized in laparoscopic surgery, however are not yet incorporated into open operations. Here, we compare thermal spread and recurrent laryngeal nerve (RLN) functional data of the integrated Thunderbeat Open Fine Jaw device, the bipolar Ligasure Small Jaw, and the ultrasonic Harmonic Focus for open thyroidectomy. Materials and Methods The three energy devices were compared in a live porcine model using three tissue types including: liver, muscle, and thyroid. The devices were fired three times on each energy setting and thermal spread was measured by thermocouples that were inserted in surrounding tissues at 1mm intervals. To determine RLN injury, devices were fired at successive 1mm increments from the RLN until the monitor signal was lost. Results When comparing heat generated across these devices at 1 mm, the peak temperature (Celsius) reached in liver tissue was observed with the ultrasonic device (115.4±86.7), in muscle tissue with the integrated device (104.2±82.1), and in thyroid with the bipolar device (81.4±41.3). Temperatures generated at individual settings on each device were similar (p=0.11-0.81). RLN injury occurred after firing on manually approximated tissue 1 mm away from the RLN for all devices, however there was no signal loss at ≥2 mm. Conclusion Heat transfer was similar among all devices with the exception of the ultrasonic device when used in the liver, which showed higher temperatures. Liver tissue showed the most consistent results. RLN injury did not occur if the devices were fired on manually approximated tissue ≥2 mm from the nerve.