To evaluate the outcome of percutaneous nephrolithotomy (PCNL) in anomalous kidneys performed at our center.

A total of 46 patients (52 renal units) with renal abnormalities were offered PCNL from January 2000 to December 2007 at our department. Of these 46 patients, 35 had a fusion anomaly (31 with a horseshoe kidney and 4 with crossed fused ectopia), 7 had malrotation, and 4 had ectopic pelvic kidneys. All 4 patients with a pelvic ectopic kidney underwent laparoscopic-assisted PCNL. The mean age was 31.5 years (range 16-52). The male/female ratio was 1.55, the left-to-right ratio was 1.3, and 6 patients had bilateral renal stones (all in horseshoe kidneys). The mean stone size was 2.4 cm (range 1-5). In addition, 8 patients (5 with a horseshoe kidney, 2 with an ectopic pelvic kidney, and 1 with a malrotated kidney) had a history of failed extracorporeal shock wave lithotripsy.

Complete clearance was achieved in all renal units (45 at the first attempt and 7 with a “relook”). The stone was cleared by a single tract in 46 renal units (88.5%), and 6 required 2 tracts (3 horseshoe kidneys, 2 malrotated kidneys, and 1 crossed fused ectopic kidney). Five patients with a horseshoe kidney underwent tubeless PCNL. The mean operating time for PCNL was 82.5 minutes (range 30-150), and the mean hospital stay was 3.2 days (range 1-8). The average decrease in hemoglobin was 1.4 g/dL (range 0.5-4). One patient developed injury to the pleura that was managed by intercostal tube drainage. Two patients developed post-PCNL sepsis.

Although PCNL in anomalous kidneys is technically demanding, it gives excellent results for large or extracorporeal shock wave lithotripsy-refractory stones, if performed carefully.