Evaluation of emissivity and temperature profile of laparoscopic ultrasonic devices (blades and passive jaws)

We examined the emissivity and temperature profile of passive and active jaws of various laparoscopic ultrasonic devices during cutting, coagulation, and cooling time.

The Harmonic ACE™ (ACE), Covidien Sonicision™ (SNC), and Olympus SonoSurg™ (SS) were applied using pre-set factory cutting and coagulation settings to Bovine mesentery and Lamb renal veins, respectively. The maximum temperature and cooling time to reach 60 °C were recorded using an infrared Fluke Ti55 thermal imager. Histological examination was evaluated after application of energy.

The ACE, Sonicision, and SonoSurg had emissivity measurements of 0.49 ± 0.01, 0.40 ± 0.00, and 0.39 ± 0.01, respectively. Maximum cutting temperatures were: ACE = 191.1°, SNC = 227.1°, and SNS 184.8° * (*p < 0.001). Maximum coagulation temperatures did not differ significantly among devices (p = 0.490). The cooling time to reach 60 °C after activation were 35.7 s (ACE), 38.7 s (SNC), and 27.4 s* (SS) (*p < 0.001). The cooling time of passive jaws to reach 60 °C after activation were 25.4 s* (ACE), 5.7 s (SNC), and 15.4 s (SS) (*p < 0.001).

Laparoscopic ultrasonic instruments obtain the same cutting and coagulation objectives but in different manners. The Sonicision improves cutting by getting the blade hotter while the SonoSurg has more precise coagulation effects by heating slower. Emissivity values varied among instruments, providing equally varied results. Depending on the purpose of the devices, a certain device may be more appropriate. Based on emissivity, more studies are needed to identify the ideal material that can predictably and effectively perform in clinical settings. Although different blade geometry is apparent between instruments, the jaws are also designed differently between the generations of instruments.