Temperature elevation in tissue during ultrasonic dissection

The temperature increase during the use of an ultrasonic surgery device was experimentally determined in vitro and in vivo with the aid of thermocouples of specific design. Temperature elevations by more than 40/spl deg/C were found at 1 mm distance from the blade, whereas at distances of more than 5 mm, perfusion removed the heat very efficiently. It is concluded that during application of the harmonic scalpel a safety margin of 3 mm from sensitive structures should be kept.