Miniaturized Ambulatory Percutaneous Nephrolithotomy Versus Flexible Ureteroscopy in the Management of Lower Calyceal Renal Stones 10-20 mm: A Propensity Score Matching Analysis

Abstract

Objective: To evaluate the efficacy of ambulatory mini percutaneous nephrolithotomy (Mini-PCNL) and flexible ureteroscope (F-URS) in treating 10-20 mm lower calyceal stones using propensity score matching analysis (PSM).

Patients and methods: A retrospective analysis of 136 adult patients that underwent Mini-PCNL or F-URS for a single lower calyx calculus. Participants that underwent F-URS were allocated to Group I, while those who underwent Mini-PCNL were assigned to Group II. Patients were discharged on the same day and followed up by CT after 3 months. Both groups were matched by stone size and density using propensity stone matching (PSM) and the matched group were further compared.

Results: Before matching, there were statistical differences in stone size (P = .02), preoperative hydronephrosis (P = .004), and Hounsfield Unit (P = .04) between both groups. A logistic regression model was created between independent variables such as stone size and density. The new groups following PSM were statistically similar in terms of age, BMI, stone size, and HFU (P = .43, P = .74, P = .49, P = .36). The stone-free rates after PSM was not significantly higher in the Mini-PCNL group than the F-URS group (91.7% vs 81.7%, respectively P = .1) while the operative time for the F-URS group was significantly shorter than the Mini-PCNL group 54 (49-64.3) minutes vs 68.2 (62-73.5) minutes, respectively, P = .045.

Conclusion: Ambulatory Mini-PCNL and F-URS have a comparable hospital stay, stone-free rates, and complication rates for treating lower calyceal stones 10-20 mm. Both techniques may be considered acceptable treatment options, with a prolonged operative time in Mini-PCNL.