Miniaturized percutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of lower pole renal stones.

Summary Objectives Miniaturization of percutaneous nephrolithotomy techniques have led to their increased consideration for lower pole renal stones that can prove more challenging to reach using retrograde intrarenal surgery. The objectives of the present study were to evaluate and compare the outcomes of miniaturized percutaneous nephrolithotomy (miniPCNL) and retrograde intrarenal surgery (RIRS) for the treatment of lower pole renal stones. Materials and methods A retrospective study was performed in two academic urology departments between January 2016 and June 2019. Patients presenting with one or multiple stones of the lower calyx and/or renal pelvis, between 10 and 40 mm based on CT-scan treated by miniPCNL or RIRS were included. Results In all, 115 miniPCNL and 118 RIRS procedures were included. The rate of patients with no significant residual fragment (stone free rate) after the first procedure was higher in the miniPCNL group (69% vs. 52% P = 0.01), especially for stones > 20 mm (63% vs. 24% respectively, P  Conclusions The stone free rate was higher after miniPCNL, especially for stones > 20 mm and with a density > 1000 HU, but was associated with a higher risk of postoperative complications and a longer hospital stay. RIRS resulted in fewer complications at the cost of a higher retreatment rate and longer ureteral stenting. Level of evidence 3.