X-Ray Free Ultrasound-Guided Percutaneous Nephrolithotomy with Endoscopic Combined Intrarenal Surgery Is Feasible, Effective, and Safe for Staghorn Calculi

Background: Percutaneous nephrolithotomy under ultrasound-guided access (US-PCNL) has multiple advantages compared with fluoroscopy. No prospective data currently examine the efficacy of this technique for the management of staghorn stones. Our objective was to determine the safety and effectiveness of US-PCNL for the management of staghorn calculi through a prospective cohort study, using strict definitions of stone free based on postoperative computed tomography (CT) imaging. Methods: Utilizing a prospective cohort of US-PCNLs performed by a single surgeon between October 2020 and September 2024, data were collected as part of Registry for Stones of the Kidney and Ureter at the University of Arizona. Inclusion criteria were the presence of staghorn stone(s) on preoperative CT imaging, with a staghorn defined as occupying the renal pelvis and either ≥2 calyces (partial staghorn [PS]) or ≥4 calyces (complete staghorn). Patients were excluded if fluoroscopy was used at any point intraoperatively or if they did not undergo a CT within 90 days postop to assess for residual stones. The primary outcomes were complete stone-free rate (SFR), rate of residual fragments <4 mm, and complication rate, with stone-free status and residual fragments measured on postoperative CT scan. Results: Of 175 PCNLs performed, 56 met inclusion criteria. Among 24 (42.9%) complete and 32 (57.1%) PSs, median aggregate linear dimension was 57.0 mm, with a median S.T.O.N.E. nephrolithometry score of 10. 19/56 (33.9%) patients were completely stone-free Grade A after a single US-PCNL, and 25/56 (44.6%) had residual fragments 4 mm or less (stone-free Grade C). The overall complication rate was 25/56 (44.6%), where the majority (20/25) were minor (Clavien–Dindo 1 and 2) with five patients (8.9%) experiencing Clavien–Dindo ≥3 complications. Conclusion: Adhering to strict criteria and outcomes, X-ray free US-PCNL can be performed for the treatment of staghorn calculi and shows comparable SFRs to those reported in prior retrospective studies with fluoroscopic PCNL.