Comparison of Mini-Percutaneous Nephrolithotomy and Flexible Ureteroscopy for Treating 1–2 cm Single Stones in Solitary Kidney: Outcomes and Renal Function Impact

Overview

This retrospective cohort study compared mini-percutaneous nephrolithotomy (mPCNL) and flexible ureteroscopy (f-URS) for managing 1.0-2.0 cm renal stones in solitary kidney patients, a population with limited treatment margin for complications. The study enrolled 50 patients over a 5-year period, with 26 undergoing mPCNL and 24 undergoing f-URS, evaluating stone-free rates, perioperative morbidity, and renal functional outcomes over a 1-month follow-up period.

Methods and approach

The analysis included retrospective data from 50 patients with solitary kidneys presenting with single renal stones measuring 1.0-2.0 cm between June 2018 and April 2024. Patients were stratified into two groups: mPCNL (n=26) and f-URS (n=24). Primary outcomes assessed were 3-month stone-free rate and Clavien-Dindo classification of complications. Secondary outcomes included hemoglobin levels, length of hospital stay, serum creatinine, and estimated glomerular filtration rate (eGFR) calculated using the CKD-EPI equation. Measurements were obtained at baseline, 72 hours postoperatively, and 1 month postoperatively.

Key Findings

Stone-free rates were equivalent between groups (mPCNL 96.2% versus f-URS 91.7%, p=0.157). The f-URS cohort exhibited significantly lower hemoglobin decline (2.2±0.9 versus 5.7±2.4 g/dL, p<0.001) and reduced hospitalization duration (4.1±1.1 versus 7.8±1.6 days, p<0.001). Grade II complications requiring transfusion occurred exclusively in the mPCNL group (8.3%). At 1-month follow-up, f-URS demonstrated greater serum creatinine reduction (15.4±7.96 versus 8.7±4.23 μmol/L, p<0.001) and superior eGFR improvement (16.7±4.7 versus 15.4±5.2 mL/min/1.73 m², p=0.023).

Implications

The findings demonstrate that f-URS achieves comparable stone clearance efficacy to mPCNL while maintaining a more favorable perioperative safety profile in solitary kidney patients. The reduced hemoglobin decline and transfusion requirement with f-URS suggest lower operative tissue trauma and blood loss, which are clinically significant in a population with solitary renal function. The enhanced early renal functional recovery with f-URS, evidenced by greater serum creatinine reduction and eGFR improvement at 1 month, suggests potential advantages for preserving long-term nephron function in this high-risk population.

These preliminary data support f-URS as a nephron-sparing alternative to mPCNL for 1.0-2.0 cm stones in solitary kidneys. The superior short-term safety profile and functional preservation characteristics are particularly relevant given the absence of renal redundancy in this population. However, the authors appropriately characterize these findings as hypothesis-generating, acknowledging the retrospective design and relatively short follow-up period.

Further prospective, randomized controlled trials with extended follow-up are necessary to establish the durability of the observed functional benefits and to evaluate long-term renal outcome trajectories. Additional investigation is warranted to determine whether the early functional advantages demonstrated with f-URS translate into sustained preservation of renal function over longer observation intervals, particularly given the critical importance of maintaining maximum renal function in solitary kidney patients.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.