Minimally invasive versus standard percutaneous nephrolithotomy: a meta-analysis

The aim of the study was to objectively analyze the outcomes for minimally invasive percutaneous nephrolithotomy (MPCNL) vs standard percutaneous nephrolithotomy (PCNL) by systematic review and meta-analysis of published data. A systematic literature review was performed in November 2014 using the PUBMED, EMBASE and Cochrane Library databases to identify relevant studies. Only comparative studies investigating MPCNL vs PCNL were included. Effect sizes were estimated by pooled odds ratio (ORs) and mean differences (MDs). The analyzed outcomes were stone-free rate (SFR), blood loss, pain assessment, operative time, hospital stay and complications. We identified 8 trials with a total 749 patients. 353 patients were treated with MPCNL and 396 with PCNL. Meta-analysis of the data showed that there was no difference in SFR between MPCNL and PCNL (OR 1.06, 95 % CI 0.71–1.58). Patients in the MPCNL group experienced less drop in hemoglobin (MD: −4.67 g/L, 95 % CI −7.29 to −2.04), a lower incidence of blood transfusion (OR 0.18, 95 % CI 0.06–0.54), less pain (visual analog score) (MD: −0.53, 95 % CI −0.94 to −0.13) and shorter hospitalization (MD: −1.32 days, 95 % CI −2.15 to −0.50). Operative time was longer in the MPCNL group (MD: 15.54 min, 95 % CI 4.25–26.83). Postoperative fever and pyelocalyceal perforation did not differ between the groups (p = 0.38 and 0.44, respectively). Current evidence suggested that MPCNL was a safe and effective procedure with an SFR comparable to that of PCNL. MPCNL resulted in less bleeding, fewer transfusion, less pain and shorter hospitalization. Well-designed multicentric/international randomized, controlled trials are still needed.