Safety and Effectiveness of Lithostar Shock Tube C in the Treatment of Urinary Calculi

Abstract

Over 14 years of clinical use of extracorporeal Shockwave lithotripsy (SWL), great technical modifications resulted in the development of many second-generation lithotripters. The Siemens Lithostar machine, with its standard Shockwave tube, was introduced in 1986. The objective of this study was to assess the safety and effectiveness of the newly proposed Lithostar shock tube C in the treatment of urinary calculi. Between July 1992 and August 1993, 319 patients (214 males and 105 females, 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 in the ureters. Most (81%) of the treated sides (side = kidney and ureter) 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 patients 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, respectively. The majority of treatments (92%) were performed without anesthesia. Fragmentation was achieved in 93.5% of treatments, with a 3-month stone-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 placement. Treatment applied on a separate occasion to different stones but in the same collecting system (either a kidney or a ureter) were considered retreatments. Based on this, 10.3% of the collecting systems (total 331) necessitated more than one treatment with an average retreatment rate (number of treatments/number of treated collecting systems) of 1.10. This retreatment rate is similar to that reported for the Dornier HM-4 machine and less than those reported using Lithostar with the standard tube. The complications reported (mostly skin effects and dysrhythmias) were mild to moderate and were treated conservatively. We conclude that SWL with Lithostar shock tube C is safe and effective with a lower retreatment rate than the currently approved Lithostar.