To compare the efficacy between super-mini percutaneous nephrolithotomy (SMP) and minimally invasive percutaneous nephrolithotomy (MPCNL) in the treatment of kidney stones with the size between 1.5 cm and 2.5 cm.

From Feb. 2016 to Dec. 2017, patients with kidney stones with the size between 1.5 cm and 2.5 cm, agreed to the treatment of percutaneous nephrolithotomy, were enrolled to the study. The patients were randomly divided into SMP groups and MPCNL groups, a total of 64 patients (32 cases for each group) met the study protocol in the end. For the SMP groups and MPCNL groups, the mean age was 43 years (range 1-67 years) and 45 years (range 9-69 years), the average stone diameter is 1.9 cm and 2.0 cm, respectively. The operative time, postoperative hospital stay, hospitalization expenses, stone free rate and complication rate between two groups were recorded and compared.

12-14 F or 16-18 F percutaneous renal access were successfully established in SMP and MPCNL group, respectively. The postoperative hospital stay was [(2.3±1.3) days vs (5.2±2.0) day, P<0.001]; The average operation time was [(92.7±28.5) min vs (72.9±17.6) min, P=0.001]; Phase I stone-free rate was [90.6%(29/32) vs 87.5%(28/32), P=0.689]; The average hospitalization expenses was [(17 371±3 584) yuan vs (19 762±4 300) yuan, respectively P=0.019]; The use of painkillers were 3 cases and 10 cases, respectively(P=0.030); The postoperative fever were 5 cases and 7 cases in the two groups, respectively (P>0.05). There was no intraoperative and postoperative blood transfusion cases in the two groups.

Both SMP and mPCNL have the advantages of minimal injury, high removal rate and less complication rate in the treatment of kidney stones with the size between 1.5 cm and 2.5 cm. Compared with MPCNL, SMP showes longer operation time but shorter hospital stay, less hospitalization costs, and the patients accepted SMP feel more comfortable after surgery.