[Clinical experience of the newly developed ultrasound lithotripter]

At present, to perform percutaneous nephrolithotomy (PNL), the ultrasound lithotripter (US) is most widely used, permitting simultaneous breakup of a calculus and suction of fragments. Recently, we have used the OLYMPUS LUS (oscillation frequency 23 kHz, maximum amplitude 60 microns) in 24 cases of renal calculi (including 6 staghorn and 5 multiple), 4 cases of ureteral calculi and 2 cases of reno-ureteral calculi. Although the degree of breakability varied depending on the substance of the calculi, cystine calculi, generally deemed relatively hard, could also be fragmented. The calculi which were found in the ureter were all situated in the upper portion of the ureter. Direct access by the US probe was possible in 1 case, but in 5 other cases the electrohydraulic lithotripter (EHL) was applied first and larger fragments blasted back into the pelvis were broken up and suctioned with the US. Residual calculi were recognized in 4 cases of 6 staghorn calculi and 2 cases of 5 multiple calculi, all of which were found within calyces and were small enough to allow spontaneous passage. In all the other 24 cases, calculi were destructed and removed with the US. We consider that most renal and ureteral calculi can be broken up and suctioned with the US, virtually regardless of the kind of substance, as long as they are situated in the areas accessible by the US probe. The 60 micron amplitude hardly posed any risk of serious injury to the renal parenchyma, not to mention the pelvic mucosa.