Temperature changes associated with radiofrequency energy–induced heating of bovine capsular tissue: Evaluation of bipolar RF electrodes

SUMMARY: This in vitro study determined the temperature changes associated with radiofrequency (RF) energy-induced heating of bovine capsular tissue using bipolar RF electrodes. Tissue samples were placed in a saline bath (37 degrees C) and RF energy was applied using 2 different types of bipolar electrodes (VAPR T End Effect and Vapor T Side Effect; Mitek, Westwood, MA). Each electrode was activated for 3 seconds at 10 W, 16 W, and 20 W, for 6 separate data acquisitions. Fluoroptic thermometry designed to be unperturbed by RF fields was used to record temperatures on the tissue surface and at depths of 2 mm, 4 mm, and 5 mm, at 1-second intervals before (5 seconds), during (3 seconds), and after (7 seconds) the application of RF energy. The highest mean temperatures were recorded at the tissue surfaces for the different power settings for each RF electrode type, as follows: End Effect: 48.9 degrees C (10 W), 57.0 degrees C (16 W), and 67.3 degrees C (20 W). Side Effect: 51.5 degrees C (10 W), 62.1 degrees C (16 W), and 71.2 degrees C (20 W). All recorded surface temperatures were within the range known to be acceptable for tissue shrinkage. Gradient effects (i.e., higher-to-lower) were observed for the tissue temperatures measured at the different depth positions. None of the temperatures recorded at the different depths were excessive, suggesting that sensitive anatomic structures should not be damaged by RF energy-induced heating under the conditions described above.