Minimally Invasive ("Mini") Percutaneous Nephrolithotomy: Classification, Indications, and Outcomes

Minimally invasive endoscopic procedures are often employed for the surgical removal of kidney stones. Traditionally, large stones are removed by (standard) percutaneous nephrolithotomy (SPCNL). Although effective for the clearance of large stone burdens, SPCNL is associated with significant morbidity. Therefore, in an effort to reduce this morbidity, while preserving efficacy, mini-PCNL (MPCNL) with a smaller tract size (<20 French) was developed. Several studies suggest that MPCNL has a comparable stone-free rate to SPCNL. However, the question of lower morbidity with MPCNL remains unanswered. In this review, we describe the equipment, indications, and efficacy of MPCNL with particular attention to its value over traditional minimally invasive stone removal techniques.