Miniaturized Versus Standard-Tract Percutaneous Nephrolithotomy for Renal Calculi Larger Than 2 cm: Tract Caliber Determines Hemorrhagic Morbidity Without Compromising Stone Clearance

BackgroundPercutaneous nephrolithotomy (PCNL) is the treatment of choice for renal calculi larger than 2 cm, but much of its morbidity arises from the access tract rather than from stone removal itself.Whether tract miniaturization preserves clearance at this stone burden, where a larger working channel might be presumed necessary, remains incompletely defined outside randomized settings.We compared perioperative outcomes of mini-PCNL and standard PCNL in a high-volume tertiary cohort. Materials and methodsWe retrospectively analyzed 215 consecutive adults undergoing PCNL for renal calculi larger than 2 cm between January 2022 and January 2026.Patients underwent mini-PCNL (16-20 Fr tract, 12-15 Fr nephroscope; n=100) or standard PCNL (24-30 Fr tract, 20-24 Fr nephroscope; n=115) according to surgeon preference.All procedures used prone, fluoroscopy-guided single-tract access with serial Amplatz dilatation and pneumatic lithotripsy.The primary outcome was the stone-free rate, defined as absence of residual fragments larger than 4 mm on computed tomography (CT) at four weeks.Secondary outcomes were operative time, hemoglobin decrement, hospital stay, and complications graded by the Clavien-Dindo classification.Differences are reported with 95% confidence intervals (CIs). ResultsBaseline characteristics were comparable.Stone-free rates did not differ (92% vs. 93.9%;absolute difference 1.9%; 95% CI -5.0 to 8.8; p=0.58), nor did operative time (80.9±18.2 vs. 76.4±21.3minutes; mean difference -4.5; 95% CI -9.9 to 0.9; p=0.10) or overall complication rate (14% vs. 19.1%;p=0.31).Mini-PCNL produced a smaller hemoglobin decrement (0.95±0.56 vs. 1.48±0.71g/dL; mean difference 0.53; 95% CI 0.36 to 0.70; p<0.001) and shorter hospital stay (2.4±0.8 vs. 3.1±1.1 days; mean difference 0.70; 95% CI 0.44 to 0.96; p<0.001). ConclusionsAt stone burdens above 2 cm, tract miniaturization reduced hemoglobin decrement by approximately onethird and shortened hospitalization by approximately 0.7 days, without loss of stone clearance or significant prolongation of operative time.Because puncture technique, dilatation method, lithotrite, and exit strategy were uniform between groups, tract caliber remains the principal variable distinguishing them.These findings support mini-PCNL as a reasonable default for large-volume non-staghorn calculi in experienced hands.