Risk factors predisposing to repeated extracorporeal shockwave lithotripsy

The Victorian Lithotripsy Service is geographically unique, representing the only Australian lithotripter for a 900-km radius and serving a patient population of over 3 million, and 26 accredited operator urologists. Because of distance and health service constraints few patients treated for renal calculi on this machine have the opportunity to seek additional treatment by extracorporeal shockwave lithotripsy (ESWL) elsewhere. The treatment histories of all patients who underwent ESWL at this center over a 4-year period were examined, with those patients who required ESWL on more than one occasion being identified and their treatment details reviewed. The retreatment rate was approximately 6%. In patients who required three or more ESWL treatments multiple calculi were present significantly more often than in the overall cohort (p < 0.05), and ESWL alone was ultimately successful in obtaining satisfactory stone fragmentation in only 62% of this group. In view of the high cost of repeated treatments by ESWL the applicability of this treatment method in cases of multiple calculi should be questioned. Initial undertreatment of calculi may also represent a significant factor in the retreatment of some radiopaque calculi.