Thermocouples were implanted in tissue surrounding the PA branch being sealed to measure tissue temperature.  A thermal camera measured the sealing site and the temperatures of the instruments.  Pathological analysis was performed on PA stumps to identify thermal damage.


 Maximum tissue heat measured by the thermocouples for the 2 US, advanced bipolar and mixed devices was 42, 39, 42 and 46°C, respectively.  The mean tissue temperatures at the site of the sealing measured with the thermal camera were 78, 75, 70 and 82°C (P = 0.834) and the mean instrument blade temperatures were 224, 195, 83 and 170°C (P = 0.000005) for the 2 US, advanced bipolar and mixed devices, respectively.  The mean diameter of the region with tissue reaching 60°C or more measured with the thermal camera was between 4 and 6 mm for the 4 devices (P = 0.941).  On pathological analysis, PA stumps had either thermal damage on the adventitia and external media (26/37) or transmural damage (11/37) at 1 mm from sealed site.



THERM