Mini percutaneous nephrolithotomy versus standard percutaneous nephrolithotomy for the management of renal stones over 2 cm: a systematic review and meta-analysis of randomized controlled trials.

Abstract

Standard percutaneous nephrolithotomy (sPCNL) is recommended for renal stones over 2 cm. Mini percutaneous nephrolithotomy (mPCNL) has also emerged as a promising technique in this setting. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the safety and efficacy of sPCNL to mPCNL for the management of renal stones over 2cm. We systematically searched PubMed, Cochrane Library and Scopus databases until April 2021 and sources of grey literature for relevant RCTs. We performed a meta-analysis of odds ratios (ORs) to compare bleeding or other complications and stone-free rate (SFR) between sPCNL and mPCNL. Similarly, we undertook a meta-analysis of weighted mean differences for the mean operative and hospitalization time between the two techniques (PROSPERO: CRD42021241860). Pooled data from 8 RCTs (2535 patients) were available for analysis. sPCNL was associated with a higher hemoglobin drop (0.59 g/dL, 95%CI: 0.4-0.77, I2=93%), higher likelihood of postoperative blood transfusion (OR: 2.58, 95%CI: 1.03-6.45, I2=30%) and longer hospital stay (0.75 days, 95%CI: 0.45-1.05, I2=73%) compared to mPCNL. No significant differences were demonstrated in SFR (OR: 0.92, 95%CI: 0.74-1.16, I2=0%) and mean operative time (4.05 minutes, 95%CI: -9.45-1.37, I2=91%) after sPCNL versus mPCNL. Similarly, no significant differences were observed for postoperative fever, pain and Clavien-Dindo complications. mPCNL represents a safe and effective technique and may be also recommended as a first-line treatment modality for well-selected patients with renal stones over 2cm. Still, further high-quality RCTs on the field are mandatory since the overall level of evidence is low.