Abstract

Introduction and Objective Percutaneous nephrolithotomy (PCNL) is a minimally invasive procedure for kidney stone removal traditionally guided by fluoroscopy. This study aimed to evaluate the feasibility and outcomes of radiation-free PCNL using ultrasound alone compared to standard fluoroscopy-guided PCNL.

Methods A total of 63 PCNL cases were eligible for radiation-free PCNL, but 27 were excluded (intra-operatively aborted, ureteroscopy performed instead, pre-operative complex anatomy). Of the remaining 36 cases eligible for radiation-free PCNL, 11 were converted intra-operatively to fluoroscopic based PCNL. Post-operative CT imaging was available for only 16 of the 25 radiation-free PCNL cases and 4 of the 11 converted cases. We designated these 16 prospective radiation-free PCNL cases (2024–2025) as Group A. For comparison purposes we identified a historical case-matched cohort of 150 PCNL’s. Of these 67 were excluded (similar reasons) leaving 83 retrospective fluoroscopy-guided PCNL cases (2022–2024) called Group B. The primary outcome was stone-free rate (SFR), assessed post-operatively by non-contrast CT (2–3 mm slices). Secondary outcomes included estimated blood loss (EBL), complication rates (Clavien-Dindo), and post-operative stone events.

Results The median pre-operative stone burden was 35 mm in Group A and 27 mm in Group B and C [p=0.3]. SFR (Grade A) was comparable across Groups A, B, and C [38%, 30%, 25% respectively (p = 0.8)]. No differences were observed in complications or secondary outcomes.

Conclusions Radiation-free PCNL is feasible and yields comparable outcomes to standard fluoroscopy-guided PCNL, offering a promising method to reduce radiation exposure without compromising surgical success. However, we identified a consistent theme of poor visualization that led to large proportion of cases requiring conversion to fluoroscopy. Innovation directed towards improving tool echogenicity is key to diffusing this technique.

Competing Interest Statement

Roger Lu Sur (RLS) has served as a speaker and received fellowship grant support from Boston Scientific. He is also a scientific advisor for Calyxo, Inc. and RetroPerc, Inc.

Clinical Trial

NCT06922006

Funding Statement

This study did not receive any funding.

Author Declarations

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

Ethics comittee/IRB of University Of California San Diego gave ethical approval for this work.

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Data Availability

All data produced in the present study are available upon reasonable request to the authors

Abbreviations and acronymsASAAmerican Society of AnesthesiologistsDOACDirect Oral AnticoagulantsEBLEstimated Blood LossIQRInterquartile RangeOROperating roomPCNLPercutaneous nephrolithotomySFRStone Free RateUCSD HealthUniversity of California San Diego Health