Re: Percutaneous Nephrolithotomy Versus Retrograde Intrarenal Surgery: A Systematic Review and Meta-Analysis

Abstract

Debate still goes on about minimally invasive treatment of urolithiasis. Meta-analysis is very important in decision-making; the level of evidence 1a represents evidence obtained from meta-analysis of randomized trials. This meta-analysis represented by De et al. reviewed the results of ten studies comparing minimicro percutaneous nephrolithotomy (mmPNL) with retrograde intrarenal surgery (RIRS). A subgroup analysis was performed comparing standard PCNL and minimally invasive percutaneous procedures (MIPPs) including mini-PCNL and micro-PCNL with RIRS, separately. Half of the studies were from Turkey. All stone burdens in these studies were lower than 2 cm except in two studies. Similarly, single stone was treated in all except for two studies. There were major differences between studies in terms of surgical techniques, follow-up procedure and imaging and definition of stone free or, in other words, clinically insignificant residual fragment. Operation time was same for RIRS and sPNL which might be because of the smaller size of stones for PNL, a debatable point. In patients with single stone about 2 cm, not surprisingly, sPNL was the leading one in stone free rates. There was a statistical confusion for other methods. According to original paper, RIRS was second one but if searched again; we can see the ‘corrigendum’ which reflected that stone free rate of mmPNL was higher than RIRS due to the correction of statistical mistake. In a special comparison between mmPNL and RIRS; RIRS had lower morbidity with lower stone free rates. Thus, as a conclusion, if the question is stone free rate, sPNL should be chosen but RIRS had the lowest morbidity with very close stone free rates to mmPNL. Although this type of studies are very important; this study did not meet expectations in decision making. It should be better to follow the European Association of Urology guidelines recommendations with evaluating whole criteria, such as comorbidities of the patients and Hounsfield unit of the stone which may reflect ‘fragility’; not only stone size