Management of Large Renal Stones in Super-mini-percutaneous Nephrolithotomy (SMP): An International Multicenter Comparative Study.

OBJECTIVES: To comparatively evaluate clinical outcomes of super-mini percutaneous nephrolithotomy (SMP) and Miniperc for treating urinary tract calculi larger than 2 cm. PATIENTS AND METHODS: An international multi-center, retrospective cohort study was conducted at 20 tertiary care hospitals across five countries (China, the Philippines, Qatar, UK, and Kuwait) between April 2016 and May 2019. SMP and Miniperc were performed in 3525 patients with renal calculi diameter larger than 2 cm. The primary endpoint was the stone-free rate (SFR). The secondary outcome objective was blood loss, operating time, postoperative pain scores, auxiliary procedures, complications, tubeless rate, and hospital stay. Propensity score matching (PSM) analysis was used to balance the selection bias between the two groups. RESULTS: 2012 and 1513 patients underwent SMP and Miniperc, respectively. After matching, 1380 patients from each group were included for further analysis. Overall, no significant difference was found in mean operation time and SFRs between two groups. However, hospital stay and postoperative pain were significantly in favor of SMP (p 4cm). The advantages of SMP was most obvious in 2-3 cm stones and eliminated as the size of the stone increased, with longer operation time in the latter two subgroups. Compared with Miniperc, the SFRs of SMP was comparable in 3-4 cm stones but lower SFR in >4cm stones. There was no statistical difference in blood transfusion and renal embolization between the two groups. CONCLUSIONS: Our data showed that SMP is an ideal treatment option for stones less than 4 cm stones and is more efficacious for 2-3 cm stones, with lower postoperative fever, less blood loss, and pain compared to Miniperc. SMP was less efficiency for > 4 cm stones with prolonged operative time.