Comparison of miniaturized percutaneous nephrolithotomy and standard percutaneous nephrolithotomy for the treatment of large kidney stones: a randomized prospective study

We aimed to compare the outcomes of mini-percutaneous nephrolithotomy (mPNL) and standard PNL techniques in the treatment of renal stones ≥ 2 cm. The study was designed as a randomized prospective study between January 2016 and April 2017. The patients with a kidney stone ≥ 2 cm were included in the study. Patients who had uncorrectable bleeding diathesis, abnormal renal anatomy, skeletal tract abnormalities, pregnant patients and pediatric patients (< 18 years old) were excluded from the study. The remaining patients were randomly divided into two groups as standard PNL and mPNL. For both group, demographic data, stone characteristics, operative data and postoperative data were recorded prospectively. The study included 160 consecutive patients who had kidney stone ≥ 2 cm. Of these, patients who met the exclusion criteria and patients who had missing data were excluded from the study. Remaining 97 patients were randomly divided into two groups as mPNL (n: 46) and standard PNL (n: 51). The mean age was 46.9 ± 13.7 and 47.4 ± 13.9 years for mPNL group and sPNL group, respectively. According to Clavien–Dindo classification, no statistical difference was detected between the groups in terms of complication rates (p 0.31). However, the rates of hemoglobin drop and transfusion rates were significantly in favour of mPNL (p 0.012 and p 0.018, respectively). Nephrostomy time and hospitalization time was found to be significantly shorter in mPNL group (p 0.017 and p 0.01, respectively). The success rate in the mPCNL group was higher than standard PNL group, however, this difference was statistically insignificant (76.5 vs 71.7%, p 0.59). Both mPNL and standard PNL are safe and effective treatment techniques for the treatment of kidney stones of ≥ 2 cm. Although there was no significant difference in success rates of both techniques; nephrostomy time, hospitalization time, bleeding and transfusion rates were in favour of mPNL.