Treatment of calculi in kidneys with congenital anomalies: an assessment of the efficacy of lithotripsy.

We studied the effectiveness of extracorporeal shock wave lithotripsy (ESWL) in the treatment of stones in kidneys with congenital anomalies to determine factors that may affect the results. Patients found to have renal calculi in kidneys with different types of congenital anomalies were treated using ESWL. All patients were investigated by intravenous urography (IVU) to confirm the diagnosis. J stents were inserted prior to therapy in renal units with calculi exceeding 1.5 cm in diameter. Complications encountered and factors affecting success using this treatment modality were analysed. Twenty-five patients (18 males, 7 females) were studied between August 1988 and July 2005. There were nine patients with horseshoe kidneys, eight with ectopic kidneys, three with malrotated kidneys, two with duplex renal system, and one patient each with polycystic kidneys and hypoplastic kidney. The IVU showed 31 isolated calyceal or renal pelvic stones with mean stone burden of 1.44cc. All 25 patients were treated by lithotripsy. Twenty-four (77.4%) renal units (in 19 patients) were completely cleared of stones, 2 (6.5%) renal units (2 patients) were partially cleared of calculi and the procedures failed in 5 (16.1%) renal units (4 patients). Out of five renal units in which the procedures failed, open surgery was performed in three renal units and percutaneous nephrolithotomy (PCNL) was performed in two. None of the 25 patients developed any major complications. No significant adverse changes in renal function tests were observed at 3-month follow-up. The stone-free rate was influenced and reduced by stone size and location in the pelvi-calyceal system. Calculi in kidneys with congenital anomalies may be treated successfully by ESWL as a first-line therapy in the majority of patients. With position modifications, localization of stones may be facilitated and disintegrated. The outcome in patients so treated does not differ significantly from that in those with normal kidneys.