{'fraction_non_alphanumeric': 0.03167155425219941, 'fraction_numerical': 0.02404692082111437, 'mean_word_length': 4.903114186851211, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Ex-vivo ureteroscopy at the time of live donor nephrectomy.

BACKGROUND AND PURPOSE
Potential transplant renal allograft recipients exceed the number of donors. Our institution now considers patients with small, unilateral, nonobstructing, incidental renal calculi for possible renal donation. We adopted ex-vivo ureteroscopy (ExURS) to render these kidneys stone free at the time of renal transplantation. We examined the safety and efficacy of ExURS.


PATIENTS AND METHODS
After confirming a lack of significant metabolic defects on 24-hour urinalysis, 23 patients with small nonobstructing unilateral nephrolithiasis detected on preoperative CT angiography underwent donor nephrectomy. Immediately after cold perfusion, ExURS was performed with ice cold saline irrigation. Retrospective review was performed.


RESULTS
Pyeloscopy was successfully performed in all 23 patients. A total of 28 calculi, mean largest diameter 3.9 mm (range 3-6 mm), were visualized in 19 kidneys. Basket extraction and holmium laser lithotripsy was performed in 12 and 6 kidneys, respectively. Treatment rendered 17/19 stone-containing kidneys stone free with a mean treatment time of 6.2 minutes (3-10 min). There were no intraoperative complications. Median serum creatinine level of recipients at 1 month and 1 year were 1.4 ± 1.8 mg/dL and 1.3 ± 0.6 mg/dL, respectively. At a median follow-up of 63 ± 47.2 months, there were no transplant urinary calculi among the recipients.


CONCLUSIONS
ExURS safely renders live donor kidney allografts stone free with low risk of recurrence. When used appropriately, ExURS could safely increase the number of potential kidney donors and minimize the risk of adverse stone events.