A retrospective study comparing super-mini percutaneous nephrolithotomy and flexible ureteroscopy for the treatment of 20–30 mm renal stones in obese patients

OBJECTIVE: This study aimed to compare the efficacy and safety of Super-mini percutaneous nephrolithotomy (SMP) and flexible ureteroscopy (F-URS) in the treatment of 20–30 mm renal stones in obese patients. METHODS: We conducted a retrospective analysis of outcomes of patients who underwent SMP and F-URS to treat 20–30 mm renal stones from August 2017 to September 2018. Patients with BMI >30 kg/m(2) were enrolled into this study. Forty-eight patients underwent SMP, while 104 patients underwent F-URS by the same surgeon. The patients’ demographic data, stone characteristics, perioperative parameters and outcomes, complications, stone-free rate (SFR) and overall costs were retrospectively assessed. RESULTS: No significant differences were found between the two groups in terms of age, gender, BMI, operation side, stone size, number, locations, stone compositions and CT value. The mean operation time was significantly shorter in the SMP group (p < 0.001), while the F-URS group had significantly shorter postoperative stays (p < 0.001) and lower complication rates (p < 0.001). Both groups had similar SFR at a 3-month follow-up (p = 0.190), while the SMP group achieved significant higher SFR 3 days after the operation (p < 0.001). The SMP group had a significantly lower overall cost and fewer stage-2 procedures than the F-URS group. CONCLUSION: SMP and F-URS are equally effective in obese patients with 20–30 mm renal stones. However, F-URS offers the advantage of a lower complication rate, while SMP performed better in terms of operation time, tubeless rate, stage-2 procedures and overall costs.