Comparative analysis of minimally invasive percutaneous nephrolithotomy and retrograde intrarenal surgery in management of lower pole renal stones (2~4 cm)

Abstract

Objective To compare the efficacy of MPCNL and RIRS in lower pole renal stones 2-4 cm in diameter. Methods A total of 167 patients who underwent MPCNL or RIRS for lower pole stone 2-4 cm in diameter between June 2011 and June 2016 were retrospectively analyzed. Lower pole stone was diagnosed with CT scan. Stone size was assessed as the longest axis of the stone. All patients were informed about the advantages, disadvantages and probable complications of both MPCNL and RIRS before the selection of the procedure. Patients were divided into two groups according to the patients' surgery type. Group 1 consisted of 98 patients who underwent MPCNL and Group 2 consisted of 69 patients treated with RIRS. Stone free statuses, postoperative complications,operative time and hospitalization time were compared in both groups. Results The mean operation time was (84±28) min vs (116 ±23) min(P<0.001); The mean hemoglobin drop value was (5.2±1.6) g/L vs (1.9±0.4) g/L (P<0.001); The postoperative hospital stay was(8.5 ± 1.4) d for MPCNL, which was longer than that of the RIRS group (3.8 ± 1.2) d (P<0.001). The respective complication rates were 14.3% (14/98) and 4.3%(3/69) (P=0.036). In MPCNL group, stone-free rate was 87.8% (86/98) at first session and 93.9% (92/98) after the additional procedure. In RIRS group, stone-free rate was 55.1%(38/69) at the first procedure and 91.3%(63/69) after the additional procedure. The final stone-free rates were similar in both groups (P=0.506). Conclusions MPCNL is an effective method for the treatment of lower pole stones 2-4 cm in diameter. RIRS should be an effective treatment alternative to MPCNL in lower pole stones, especially in selected patients. Key words: Renal stone, lower pole; Percutaneous nephrolithotomy; Ureteroscope