Extracorporeal shock wave lithotripsy. An update.

Extracorporeal shock wave lithotripsy has revolutionized the treatment of urinary calculi. It should be considered the treatment of choice for renal stones smaller than 2 cm and for the majority of ureteral calculi, under which circumstances success rates approaching 80 to 90 per cent may be anticipated. Larger renal calculi or impacted ureteral stones probably should be managed by endoscopic techniques with or without adjunctive intracorporeal (ultrasonic or electrohydraulic) lithotripsy or laser fragmentation. Recent modifications in lithotripter design have been focused on the development of pain-free lithotripsy. Concomitant with a decrease in power, however, is an attendant decrease in the efficiency with which stones can be fragmented, resulting in an increase in the number of lithotripsy treatments required for adequate stone fragmentation. Additionally, sonography is assuming an increasing role in stone localization, and its use will require sonographic training on the part of the urologist. Biliary lithotripsy has been promising in preliminary European studies, with success rates approaching 90 per cent. It must be noted, however, that the U.S. experience has not been as impressive. Moreover, only 20 to 30 per cent of patients referred for biliary lithotripsy appear to be optimal candidates for this new technique. Adjunctive dissolution of gallstones with chronic oral medical therapy may be required after biliary lithotripsy, and long-term follow-up studies still need to be performed. Finally, the potential deleterious effects of extracorporeal shock wave lithotripsy must always be kept in mind. Although the majority of clinical and animal investigations have documented no significant long-term alterations in renal function, care must still be exercised when performing lithotripsy with the knowledge of the potential for long-term injurious effects on the functioning renal parenchyma.