Fundamental mechanisms and pitfalls of scissors-type ultrasonically activated devices

In an ultrasonically activated device, electric energy is transformed to me chanical vibration, which is transmitted to the device's tip. By clamping t he vessel between the tissue pad and vibrating blade, frictional heat is ge nerated. This heat, significantly milder than that in electrocautery techni que, is ideal for sealing the vessel. The ultrasonic vibration eventually d ivides the vessel. In the experimental studies, the cut end of medium-sized vessels divided by a scissor type ultrasonically activated device (USAD) w ithstood high intravascular pressure. However, our clinical experiences wit h the USADs suggest there are pitfalls including: - giving excessive tensio n to the vessel, - incomplete clamping of the vessel, - contacting the adja cent vessel with the back side of the active blade tip, - contacting the ad jacent vessel with the blade tip. Some devices are described to prevent the se pitfalls. (C) 2000 Editions scientifiques et medicales Elsevier SAS.