Super-mini percutaneous nephrolithotomy (SMP) is a novel miniaturized PCNL technique in the management of renal stone disease.We have recently shown that SMP is a safe and feasible in both adult and pediatric population with moderate renal calculi size. The aim of this study was to compare the efficacy and safety of Super-mini percutaneous nephrolithotomy (SMP, F12-F14) and Miniperc (F18) in the treatment of renal stones of 2-4 cm in size.
A prospective comparative analysis of outcomes of patients who underwent SMP and Miniperc for treatment of 2-4cm renal stones was conducted between July 2014 and January 2017. Patients who underwent other concurrent surgical procedures, pregnant at the time of operation, history of renal malformation, and patients with inadequate correction of coagulopathy pre-operatively were excluded from the study. Demographic data, stone criteria, operative technique, complications, blood transfusion, hemoglobin decrease, stone-free rate (SFR) and length of hospital stay were compared between the two groups. Propensity score matched analysis was performed to further compare the outcomes between the two groups.
336 patients with renal stone larger than 2 cm were treated at our center, with 79 and 257 patients underwent SMP and Miniperc, respectively. The stone burden was comparable for both groups (3.0Â±1.0 vs 3.1Â±0.8 cm, p=0.915). Mean operation time was not significantly different between two groups (p=0.144), while the hospital stay of SMP was much shorter than Miniperc (2.6 Â± 1.4 vs 5.3 Â± 2.0, p<0.001). SFR in postoperative 1 day was similar between two groups (86.1% vs 79.7%, p=0.209), while a higher clearance rate was achieved by SMP at 1 month follow up (93.7% vs 84.1%, p=0.03). The tubeless rate was significantly lower in the Miniprec group than in the SMP group (82.3% vs 52.2%, p<0.001). No difference was observed between two groups regarding complications (15.2% vs 21.0%, p=0.255). After matching, 73 patients in each group were included. The results were also true after propensity score matching (PSM), while the total complication rate was significantly lower in SMP after PSM (16.4% vs 41.1%, p=0.0001), and the SIRS rate was markedly lower in SMP group (1.4% vs 12.3%, p=0.009).
SMP is equally effective as Miniperc in the treatment of large renal calculi and has the significant advantage in hospital duration. Also, SMP can be performed more safely than Miniperc with less SIRS and more acceptable for patients in terms of a higher tubeless rate.