Comparative study of the treatment of 20-30 mm renal stones with miniaturized percutaneous nephrolithotomy and flexible ureterorenoscopy in obese patients

To evaluate and compare flexible ureteroscopy (f-URS) and mini-percutaneous nephrolithotomy (mPNL) for 20-30 mm renal stones in obese patients regarding efficacy and safety. Between May 2011 and June 2017, 254 obese patients who had 20-30 mm kidney stone were consecutively included in the study; 106 patients underwent mPNL and 148 underwent f-URS by the same surgeon. The following parameters were retrospectively assessed: patient and stone characteristics, surgical details, perioperative outcomes, and stone-free rates (SFR). F-URS group was similar to mPNL group in terms of the mean duration of surgery (92.8 +/- 26.1 vs 87.4 +/- 31.5 min, P = 0.137) and the final SFR (89.1 vs 92.5%, P = 0.381). The f-URS group had significantly shorter postoperative stay (1.0 +/- 0.8 vs 4.3 +/- 1.7 days, P < 0.001) and lower postoperative complications (11.5 vs 26.4%, P = 0.002). However, the f-URS group had a lower SFR after first session (67.2 vs 87.4%, P < 0.001) and needed more number of procedures (1.5 +/- 0.4 vs 1.3 +/- 0.4, P < 0.001) than the mPNL group. MPNL has a higher efficacy (higher SFR after first session and lower number of procedures); however, f-URS offers advantages regarding safety (lower complication rate). Therefore, both options can be offered to obese patients with renal stones from 20 to 30 mm in size. Nevertheless, these results must be confirmed by further prospective randomized trials.