Mini-percutaneous nephrolithotomy: Is smaller better for kidney stones in patients with neurogenic bladder?

INTRODUCTION: Patients with neurologic bladder are at an increased risk for urolithiasis, and currently, data on mini-percutaneous nephrolithotomy in this population are limited. Our objective was to compare mini (15F)-percutaneous nephrolithotomy, standard (24F)-PCNL and flexible ureteroscopy in terms of efficacy and safety in treatment of kidney stones in patients with neurogenic lower urinary tract dysfunction (NLUTD). METHODS: We conducted a retrospective monocentric study in our neuro-urological referral centre. All consecutive patients with NLUTD and a cumulative size of renal calculi greater than 15mm or 10mm in the lower calyx, who had extraction surgery between 2005 and 2020, were included. The primary endpoint was the one-session stone-free rate (SFR) at 3 months on a CT scan. The secondary endpoints were complication (Clavien-Dindo grading system), operative time, blood loss and length of hospital stay. RESULTS: We performed 76 standard PCNL (sPCNL), 46 flexible ureteroscopy lithotripsy (fURL) and 25 miniaturized PCNL (mPCNL). The one-session SFR was 37.5% for the mPCNL group, 38.2% for the sPCNL group and 37% for the fURL group with no significant difference between the three procedures (P=0.99). Early complications, blood loss and transfusion rates were lower in the mPCNL group than in the sPCNL group (P=0.047) and comparable to fURL group. The final SFRs after a second intervention for mPCNL, sPCNL and fURL were 48%, 61.8% and 63%, respectively (P=0.67). CONCLUSION: The efficacy of mPCNL in patients with NLUTD was not different from other techniques, but a significantly lower rate of complications than sPCNL was observed. LEVEL OF PROOF: 3.