175 of the inner tube 170 the ultrasonic waveguide 179 is preferably substantially semi flexible it will be recognized that the ultrasonic waveguide 179 may be substantially rigid or may be a flexible wire the ultrasonic waveguide 179 may for example have a length substantially equal to an integral number of one half system wavelengths n u03bb 2 the ultrasonic waveguide 179 may be preferably fabricated from a solid core shaft constructed out of material which propagates ultrasonic energy efficiently such as titanium alloy i e ti 6al 4v or an aluminum alloy it is contemplated that the ultrasonic waveguide 179 may be fabricated from any other suitable material the ultrasonic waveguide 179 may also amplify the mechanical vibrations transmitted to the ultrasonic blade 88 as is well known in the art as illustrated in fig2 the ultrasonic waveguide 179 may include one or more stabilizing silicone rings or damping sheaths 110 one being shown positioned at various locations around the periphery of the ultrasonic waveguide 179 the damping sheaths 110 dampen undesirable vibration and isolate the ultrasonic energy from the inner tube 170 assuring the flow of ultrasonic energy in a longitudinal direction to the distal end of the ultrasonic blade 88 with maximum efficiency the damping sheaths 110 may be secured to the ultrasonic waveguide 179 by an interference fit such as for example a damping sheath described in u s patent application ser no 08 808 652 hereby incorporated herein by reference referring.