Chen HQ, et al. - Authors aimed to compare flexible ureteroscopy (f-URS) and mini-percutaneous nephrolithotomy (mPNL) to assess the efficacy and safety in the treatment of 20–30 mm renal stones in obese patients. A higher efficacy (higher stone-free rates (SFR) after the first session and lower number of procedures) of mPNL was noted; nonetheless, advantages regarding safety (lower complication rate) were provided by f-URS. Hence they noted that in obese patients with renal stones from 20 to 30 mm in size, both these options could be offered.