Flexible Ureteroscopy Versus Mini-Percutaneous Nephrolithotomy for Treatment of Renal Stones

Management of nephrolithiasis is evolving rapidly, and various minimally-invasive urological procedures are currently available for treating patients with renal stones, including extracorporeal shockwave lithotripsy (ESWL), flexible ureteroscopy (f-URS) and miniaturised percutaneous nephrolithotomy (mini-PCNL).

Despite being the only truly-non-invasive, outpatient procedure, stone-free rates (SFRs) of ESWL are lower than both mini-PCNL and f-URS. Furthermore, ESWL has several limitations, such as pregnancy; uncorrected coagulopathy;aortic aneurism; severe obesity; large stone burdens (>2cm); stones with high densities (>970/1000 Hounsfield units); ESWL-resistant stone compositions; lower calyceal stones with unfavourable anatomical criteria; and stones in calyceal diverticula; Morbidities of the conventional PCNL are significantly minimised by using less access diameters in PCNL while providing comparable SFRs. Additionally, Mini and Micro PCNL result in shorter hospital stay and higher tubeless rates compared to conventional PCNL.

Flexible ureteroscopy has been increasingly used as a primary modality for treatment of renal stones with significantly lower complication rates than PCNL and mini-PCNL in terms of less bleeding and transfusion rates, shorter hospital stay and less postoperative pain. Additionally, f-URS is the only treatment modality of nephrolithiasis that can be safely and effectively used in patients with bleeding tendency, as well as pregnant women; moreover, its outcomes are not affected by obesity. Nevertheless, its poor durability and high costs remain major limitations for f-URS, especially in developing countries.