Modern Outcomes with Modified PCNL

Percutaneous nephrolithotomy (PCNL) is the treatment of choice for patients with renal calculi ≥ 2 cm as well as larger lower pole calculi [1,2]. The armamentarium of specialized rigid and flexible nephroscopes and powerful lithotripters allow for greater stone-free rates in the treatment of patients with large stone burdens [3]. However, in comparison to shockwave lithotripsy and ureteroscopy, PCNL is associated with greater morbidity, particularly with respect to bleeding risk. This is attributed to the creation of a nephrostomy tract with subsequent tract dilation resulting in shearing of renal parenchyma and bleeding [4]. As such, percutaneous surgery using smaller tracts has been explored as a means to limit the morbidity of PCNL. An assortment of options ranging from micro-, to ultramini-, to miniPCNL have been described [5-7]. Recent series have demonstrated improvements in bleeding risk [8], postoperative pain scores [9] and hospital length of stay [10] compared with standard PCNL. However, despite these benefits, technical limitations apply. Smaller access tracts require miniaturized instruments, precluding the use of many efficient stone fragmentation and retrieval devices routinely used in standard PCNL. Therefore, while reported stone-free rates are generally high, these studies are often limited to patients with stone burdens between 10-20 mm [5,6,8].