Extracorporeal piezoelectric shock wave lithotripsy as mono and multiple therapy of large renal calculi including staghorn stones in unanaesthetized patients under semi-ambulant conditions

OBJECTIVE: To examine the effectiveness and complication rate of extracorporeal piezoelectric shock wave lithotripsy (EPL) as monotherapy for the treatment of large renal calculi. PATIENTS AND METHODS: Treatment consisted of semiambulant EPL as monotherapy combined with protective ureteric stenting in 84 patients. Three groups were established according to stone volume (borderline-stone, partial and complete staghorn). An average of 18,230 shock waves was applied in 3.76 sessions to each patient. RESULTS: No major complications were observed but there were minor complications in 33% of patients. Invasive auxiliary methods were necessary in only 12%. After a mean follow-up of 9 months (n = 72), 54% of patients were stone-free and in 22% the fragments passed spontaneously. Thus the success rate was 76%. Analysis of the three groups showed no difference in stone status during follow-up. There was no relation between the outcome of treatment and stone volume. Analysis of the patients who failed to respond to treatment showed that they were treated for longer than the stone-free group, with significantly fewer sessions per week (0.71 vs 1.28 sessions/week). It appears that higher rates of stone removal can be achieved with more frequent treatment sessions at shorter intervals. CONCLUSION: We consider semi-ambulant EPL monotherapy to be a minimally invasive alternative treatment in patients with large renal calculi, including staghorn stones.