SAFETY AND EFFECTIVENESS OF LITHOSTAR SHOCK-TUBE-C IN THE TREATMENT OF URINARY CALCULI

Over 14 years of clinical use of extracorporeal shockwave lithotripsy (SWL), great technical modifications resulted in the development of ma ny second-generation lithotripters. The Siemens Lithostar machine, wit h its standard shockwave tube, was introduced in 1986. The objective o f this study was to assess the safety and effectiveness of the newly p roposed Lithostar shock tube C in the treatment of urinary calculi. Be tween July 1992 and August 1993, 319 patients (214 males and 105 femal es, average age 49.7 years) with 433 renal or ureteral stones or both were treated at five centers in Canada and the United States. Most of the stones (72%) were located in the kidneys, while 28% were located i n the ureters. Most (81%) of the treated sides (side = kidney and uret er) presented with single stones, 11% presented with two stones, and 8 % presented with three or more stones. The average stone burden was 13 .6 mm. The average duration of treatment for the whole population of p atients was 39.3 minutes using an average number of shockwaves of 3633 in a minimum and maximum energy setting of 0.11 and 3.82, respectivel y. The majority of treatments (92%) were performed without anesthesia. Fragmentation was achieved in 93.5% of treatments, with a 3-month sto ne-free rate of 62.5% and a success rate (stone free or fragment <5 mm ) of 72%. Auxiliary procedures were necessary in conjunction with 108 treatments, and most of them were in the form of catheter/stent placem ent. Treatment applied on a separate occasion to different stones but in the same collecting system (either a kidney or a ureter) were consi dered retreatments. Based on this, 10.3% of the collecting systems (to tal 331) necessitated more than one treatment with an average retreatm ent rate (number of treatments/number of treated collecting systems) o f 1.10. This retreatment rate is similar to that reported for the Dorn ier HM-4 machine and less than those reported using Lithostar with the standard tube. The complications reported (mostly skin effects and dy srhythmias) were mild to moderate and were treated conservatively. We conclude that SWL with Lithostar shock tube C is safe and effective wi th a lower retreatment rate than the currently approved Lithostar.