A Critical Review of Miniaturised Percutaneous Nephrolithotomy: Is Smaller Better?

Context: In an effort to reduce morbidity related to percutaneous nephrolithotomy (PCNL), some investigators have progressively introduced miniaturised approaches. The development of miniaturised nephroscopes facilitated widespread dissemination of these techniques and a significant expansion of the role of PCNL in endourology. Objective: To discuss the different techniques comprising modern PCNL and identify the pros and cons of each of them. Evidence acquisition: Data for this review were identified through a search of PubMed, including studies published in the last 20 yr in core clinical journals in English. The search terms included "urolithiasis", "nephrolithiasis", or "urinary stones" in combination with "miniaturised PCNL", "mini-PCNL", "micro-PCNL", "minimally invasive PCNL", and "ultramini PCNL". Publications relevant to the subject were retrieved and critically appraised. Evidence synthesis: The indications for miniaturised PCNL have not been standardised yet. Even though data in the literature reveal limitations and conflicting results, these techniques seem promising in terms of effectiveness and safety for the treatment of renal stones. The development of miniaturised scopes facilitated knowledge of the physics behind the vacuum cleaner effect generated during procedures, and greater efficacy of holmium laser generators and surgeon skill have led to progressive expansion of the indications for miniaturised techniques. Well-designed, randomised, multi-institutional studies are needed to better understand the indications for these miniaturised techniques before considering them a standard procedure for potential replacement of conventional PCNL. Conclusions: Miniaturised PCNL represents a valuable new tool in the armamentarium of modern endourologists, capable of offering good outcomes with lower complications rates compared to the standard technique and higher cost effectiveness compared to flexible ureteroscopy. Patient summary: Miniaturised percutaneous nephrolithotomy represents a safe and effective alternative to standard techniques for the treatment of renal stones. Each patient needs to be considered individually and tailored surgical treatment has to be offered. (C) 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.