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

Abstract

Extracorporeal shock wave lithotripsy (ESWL^§) and percutaneous nephrostolithotomy (PCNL) have been utilized 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 was reviewed in the treatment of 60 renal units (43 patients) with symptomatic cystine calculi.

When ESWL was used as the sole modality of treatment for cystine calculi 20 mm or smaller in diameter (17 patients), a stone-free rate of 70.5% at three months was achieved, compared to a previously reported stone-free rate of 76% for all types of stones. Forty percent of cystine stones larger than 20 mm or staghorns (10 patients) were stone free at three months v 41% for all stone types. Cystine stones required an increased number of treatments per renal unit (1.44) and total number of shock waves (2,109) compared to non-cystine calculi (1.17 treatments, 1,486 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, since 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 three months are much higher (92%) when compared to ESWL (40%), while the need for multiple sessions is comparable.