Comparison of escalating, constant, and reduction energy output in ESWL for renal stones: multi-arm prospective randomized study.

This study was designed to find out the optimized energy delivery strategy in Shock Wave Lithotripsy (SWL) that yield to the best stone-free rate (SFR). In this clinical trial, 150 consecutive patients were randomized into three groups: (a) Dose escalation, 1500 SW at 18 kV, followed by 1500 SW at 20 kV then 1500 SW at 22 kV. (b) Constant dose, 4500 SW at 20 kV. All patients undergo plain X-ray film of the urinary tract at day 1, 14, and 90 to assess stone-free rate (SFR) which was defined as no stones or painless fragments less than 4 mm. (c) Dose reduction, 1500 SW at 22 kV, followed by 1500 SW at 20 kV and then 1500 SW at 18 kV. The three treatment groups were comparable in terms of age, sex, stone size and distribution of the kidneys, and the need for Double J stent use. On day 90, the SFR achieved was 82, 90, and 84 % in the escalating, constant, and reduction energy groups, respectively. However, this rate was not statistically significant (x 2 = 1.38, p level = 0.28). At a slow rate of 60 shocks, there was no difference in stone-free rate between different voltages at 1, 14, and 90 days. Our randomized clinical trial showed no statistically significant difference in SFR between the three groups while using the slow SWL rate. Our trial is the first randomized trial comparing the three strategies. As such, a dose adjustment strategy while delivering SWL in slow rate was not recommended.

Effect of modification of shock-wave delivery on stone fragmentation.

PURPOSE OF REVIEW: Shock-wave lithotripsy has been the mainstay of urinary-stone treatment over the past 20 years, with three generations of lithotripters now in the market place. Little improvement, however, has been made in the overall efficiency, since the original Dornier HM3 lithotripter. Over the past 5 years much progress has been made in the basic research of shock-wave lithotripsy, with better understanding of the mechanisms involved in stone fragmentation. This progress has led to new modifications in the way shock-wave pulse is generated and delivered. RECENT FINDINGS: Clinical studies, reflecting improved understanding of basic mechanisms of stone comminution, are being published. Two recent prospective clinical trials have shown the higher efficiency of slow-rate compared with fast-rate shock-wave lithotripsy. A very practical solution requiring no hardware upgrade albeit at longer procedure times. Other promising developments include the use of twin-head technology, with either simultaneous or sequential shock waves. In addition, chemolytic pretreatment and dose-escalation techniques have shown early encouraging results. This review provides an update of the latest shock-wave technology and delivery strategies. SUMMARY: Long-term studies, to document anticipated improved safety with slow shock-wave rate, are needed. Future in-vivo and clinical studies of twin-head technology and dose-escalation strategy of shock-wave lithotripsy may initiate new lithotripter designs that will lead to improved stone-free rates, while simultaneously reducing associated renal trauma.

Slow versus fast shock wave lithotripsy rate for urolithiasis: a prospective randomized study.

PURPOSE: We determined the effect of shock wave lithotripsy (SWL) rate on treatment outcome in patients with renal and ureteral stones. MATERIALS AND METHODS: A total of 156 patients were prospectively randomized to receive SWL using a slow (60 pulses per minute) or fast wave rate (120 pulses per minute). Inclusion criteria were patients with a single radiopaque renal or ureteral stone not exceeding 30 mm in maximum diameter. Patient characteristics, stone and therapy features were reviewed, and the relation to success rate and total number of shock waves required was assessed using the chi-square, Fisher exact and Mann-Whitney tests. Factors proven to be significant in univariate analysis were entered in a multivariate logistic regression analysis. RESULTS: The study included 114 male (73.1%) and 42 female (26.9%) patients with a mean age +/- SD of 42.1 +/- 13.3 years. Stone length measured in maximum diameter was 13.2 +/- 5.9 mm (range 5 to 30). Renal stones were encountered in 94 (60.3%) patients and ureteral stones in 62 (39.7%). The slow SWL rate was used in 76 (48.7%) patients and the fast rate in 80 (51.3%). Baseline variables were comparable in both groups. However, the total number of shock waves required was statistically significantly lower in the slow rate group (p = 0.004) and the treatment time was significantly longer (p = 0.000). The rate of success, defined as being completely stone-free or having clinically insignificant gravel less than 2 mm, was significantly higher with the slow rate (p = 0.034), an increased number of sessions (p = 0.001), decreased stone length (p = 0.000) and greater total number of shock waves (p = 0.011). However, only the slow SWL rate and stone length maintained a statistically significant impact in multivariate analysis. CONCLUSIONS: The slow SWL rate is associated with a significantly higher success rate at a lower number of total shock waves compared to the fast SWL rate.

Survival and prognostic factors in renal cell carcinoma in Saudi patients: A ten year review.

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