Ex vivo Stone Clearance During Kidney Transplantation: A Single-Center Case Series to Expand Living Donor Eligibility

Abstract

Background: The growing disparity between the demand for kidney transplantation and the availability of suitable grafts has prompted expansion of living donor acceptance criteria. Objective: To evaluate the feasibility and safety of ex vivo stone clearance in living donor kidneys during transplantation and its role in expanding donor eligibility. Methods: This retrospective single-center case series included five living kidney donors with incidentally detected, non-obstructive renal calculi who underwent ex vivo stone clearance at the time of transplantation between June 2024 and October 2025. Donors were selected based on solitary or limited stones ≤15 mm without hydronephrosis, infection, or metabolic abnormality. Following laparoscopic donor nephrectomy and cold perfusion, bench pyelolithotomy or ex vivo flexible ureteroscopy was performed. Primary outcomes were stone-free status and early graft function. Secondary outcomes included cold and warm ischemia times and perioperative complications graded by Clavien–Dindo classification. Results: Complete stone clearance was achieved in all grafts (100%). Mean stone size was 8.4 mm (range 5–14 mm). Bench pyelolithotomy was performed in three cases and ex vivo ureteroscopy in two. Mean cold ischemia time was 65.6 minutes, and mean warm ischemia time was 3.8 minutes. All recipients demonstrated immediate graft function with serum creatinine declining to a mean of 1.1 mg/dL at discharge. No delayed graft function, major complications, or stone recurrence were observed at a median follow-up of nine months. Conclusion: Ex vivo stone clearance in carefully selected living donor kidneys is safe and effective. Bench stone surgery allows complete calculi removal without compromising early graft outcomes and may represent a practical strategy to responsibly expand living donor eligibility.