Optimal Management of Lower Polar Calyceal Stone 15 to 20 mm

PURPOSE: To compare the stone clearance rate, efficiency quotient (EQ), and early complications of shock wave lithotripsy (SWL) and percutaneous nephrolithotomy (PCNL) for solitary lower-pole renal stones measuring 15 to 20 mm. MATERIALS AND METHODS: This was a retrospective matched-pair analysis of 142 patients (78 in the SWL and 64 in the PCNL group). Preoperative imaging was done by use of noncontrast computed tomography (CT kidney, ureter, and bladder [KUB]), intravenous urogram, or plain X-ray and ultrasound KUB to assess the largest dimension of the stones. Only patients with radiopaque stones were included. The stone-free rates were assessed with plain X-ray and ultrasound at 4 weeks. Data were analyzed by use of SPSS ver. 19. RESULTS: The patients' demographic profiles (age, body mass index) and the stone sizes were comparable in the two groups. The mean stone size was 17.4±2.12 in the PCNL group compared with 17.67±2.04 in the SWL group (p=0.45). At 4 weeks, 83% of patients undergoing PCNL were stone-free compared with 51% in the SWL group (p<0.001). The EQ for the PCNL group was 76% compared with 44% for the SWL group (p<0.001). Ancillary procedures were required by 9% of patients in the PCNL group compared with 15% in the SWL group. The complication rate was 19% in both groups. The SWL complications were minor. CONCLUSIONS: Stone clearance from the lower pole of solitary stones sized 15 to 20 mm at the greatest diameter following SWL is poorer. These calculi can be better managed with percutaneous surgery owing to its higher efficacy and acceptably low morbidity.