| 摘要 |
<p>An ultrasonic surgical tool has an elongate waveguide (102) operatively connected or connectable to a source of ultrasonic vibrations. An operative element (100, 130, 140) at a distal end of the waveguide (102) has a diameter less than that of the waveguide (102). A connecting portion of intermediate diameter may connect the operative element (100, 130, 140) and the waveguide (102). A proximal end of the operative element (100, 130, 140) forms a first step junction (126, 134), located at a nodal plane of ultrasonic vibrations in the waveguide (102) and operative element, producing a velocity amplitude gain across the step junction. A second zero-gain step junction between the connecting portion and the waveguide (102) is located at an antinodal plane. The operative element (100, 130) may comprise a curved distal cutting and welding element (114) having a pair of elongate welding grooves defining a cutting ridge. Alternatively, the operative element (140) may comprise a welding element having a flat or slightly ridged operative face (136).</p> |
