Cystine stones: the efficacy of percutaneous and shock wave lithotripsy.

Cystinuria is a rare cause of renal calculi, whose management presents a complex problem mainly due to the hardness and high recurrence rate of cystine stones. During the period 1987-1991, 28 established cases of cystine calculi were treated by extracorporeal shock wave lithotripsy (ESWL) and percutaneous nephrolithotripsy (PCNL). These cases were divided into 5 groups, according to the position and size of the stones, and each group then followed a specific regimen, either ESWL monotherapy or a combined treatment comprising an initial ESWL treatment followed by PCNL or vice versa. ESWL monotherapy provided satisfactory results only in the group with pelvic stones (54.5% success rate), with 2.16 stone treatments/renal unit, and only with calculi smaller than 2.5 cm. The groups with multiple stones or staghorn calculi were treated with a combined treatment of ESWL and PCNL and had success rates of 50 and 67%, respectively. However, the group in which PCNL was followed by ESWL showed a clear advantage over the group in which ESWL was administered before PCNL, since it required a smaller number of ESWL treatments (1,5 stone treatments/renal unit as compared to 4.3 stone treatments/renal unit). Finally, attempts for ESWL in situ in the few cases of ureteral stones proved unsuccessful.