Comparative study of long-term stone recurrence after extracorporeal shockwave lithotripsy and open stone surgery for kidney stones

Background: Extracorporeal shock wave lithotripsy (ESWL) has become the tre atment of choice for most calculi of upper urinary tract and the need for o pen stone surgery (OSS) have considerably reduced. However, stone recurrenc e is often encountered as a long-term problem requiring re-treatment. Methods: In the present retrospective study, the recurrence rates of ESWL a nd OSS were compared in the treatment of kidney calculi. During the 1 year period of the present study, 43 patients were treated by OSS and 400 underw ent ESWL (the Dornier MPL 9000 lithotriptor), The recurrence of stone was d efined as reappearance of the stone on plain abdominal radiography during t he follow-up period. Results: Complete removal of all stone fragments was achieved in 51.2% of p atients (n = 22) treated with OSS. In the ESWL group, the stone free rate w as 56.7% (n = 237). The recurrence rate was 31.8% within a mean of 40 month s (range 32-48 months) in the OSS group, whereas this figure was 13.9%, wit h a mean period of 46 months (range 42-48 months) in the ESWL group (P < 0. 05). The mean periods of recurrence in ESWL and OSS groups were 20 (range 6 -42 months) and 11 months (range 8-44 months), respectively (P < 0.05). How ever, the mean stone burdens of both groups were different (2.9 +/- 0.8 vs 1.4 +/- 1.1 cm). For comparable stone burdens, the recurrence rate was simi lar. In the ESWL group, stones in the lower calyx, multiple stones and larg er stones showed a higher recurrence rate. The recurrence after OSS was als o influenced by stone burden. Conclusions: The results of the present study demonstrate that stone burden may be the primary risk factor for stone recurrence after ESWL and OSS.