Relative Efficacy of Extracorporeal Shock Wave Lithotripsy and Percutaneous Nephrostolithotomy in the Management of Cystine Calculi

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Abstract
Both extracorporeal shock wave lithotripsy (ESWL; Dornier Medical Systems, Marietta, GA) and percutaneous nephrostolithotomy (PCNL) have been used in the treatment of cystine calculi. However, it has been reported anecdotally that this stone type is resistant to fragmentation during ESWL. Therefore, the relative efficacy of ESWL and PCNL were reviewed in the treatment of 60 renal units (43 patients) with symptomatic cystine calculi. When ESWL was used as the sole modality for calculi 20 mm or smaller in diameter (17 patients), a stone-free rate of 70.5% at 3 months was achieved, compared with a previously reported stone-free rate of 76% for all types of stones. Forty per cent of patients with cystine stones larger than 20 mm or staghorns (10 patients) were stone free at 3 months ν 41% for all stone types. Cystine stones required an increased number of treatments per renal unit (1.44) and total number of shock waves (2109) compared with other types of calculi (1.17 treatments, 1486 shock waves). Although cystine calculi are more resistant to fragmentation with ESWL, this noninvasive modality can be appropriately applied to cystine calculi 20 mm or smaller in diameter, as reasonable stone-free rates are achieved. However, for cystine calculi larger than 20 mm or for staghorn calculi, PCNL is preferred, as stone-free rates at 3 months are much higher (92%) than with ESWL (40%), while the need for multiple sessions is similar.