Kidney stone management in the era of miniaturized percutaneous nephrolithotomy: does it improve safety? a prospective cohort study

to compare the safety and the efficacy of standard percutaneous nephrolithotomy (sPCNL) vs. mini PCNL (mPCNL). METHODS: The authors conducted a prospective single-centre cohort study over a 2-year period of all consecutive patients who underwent sPCNL or mPCNL for 2–4 cm renal stones. Patients with active urinary tract infection, abnormal coagulopathy state, malformative uropathies and multitract-access procedures were excluded. In total, 90 patients underwent sPCNL using a 30 Fr access sheath with 24 Fr nephroscope while 52 patients underwent mPCNL using a mPCNL system: 12 Fr nephroscope and a 16.5/17.5F access sheath. Blood loss estimation was assessed postoperatively after 6 h by considering haemoglobin drop and blood transfusion if required. Stone free rate at 1 month was defined by the absence of stone or residual fragments less than or equal to 3 mm on computed tomography scan. RESULTS: Stone characteristics were comparable in both treatment arms. The mean stone size was comparable for sPCNL and mPCNL groups (32.6±10.8 mm vs. 29.4±11.8 mm). Operative time was longer in the mPCNL group (124±40.4 min vs. 95.8±32.3 min, P<0.001). According to the Clavien–Dindo classification, no statistical difference was found between the groups in terms of complication rate (P=0.092). However, the mean of haemoglobin drop and transfusion rate were significantly in favour of mPCNL (1.43±1.5 vs. 0.88±1.4 g/dcl, P=0.04). Hospital stay was found to be significantly shorter for patients undergoing mPCNL (4.4±3.9 vs. 2.7±1.7 days, P<0.001). The success rate in the sPCNL group was higher than mPCNL group in terms of stone clearance at one month (69.4% vs. 62.7%, P=0.06). CONCLUSION: Both sPCNL and mPCNL have shown good outcomes in this indication. Although the stone free rate was equal for both techniques, hospital stay, bleeding and transfusion rate are much lower with the use of mPCNL.