Urolithiasis in allograft kidneys.

OBJECTIVES: Allograft stones are an uncommon clinical problem and management is mainly based on anecdotal experience, rather than analysis of larger series.
METHODS: In an 8-year period, 19 patients were treated for 19 renal and 3 ureteral stones. In 9 patients, stones were transplanted and 10 formed de novo stones within a mean of 28 months (range 13 to 48) after transplantation. In 4 patients, stones were removed during transplantation. Seven patients were treated with extracorporeal shock wave lithotripsy (ESWL), 3 patients had stones removed percutaneously, 1 by antegrade ureteroscopy, and 1 at the time of ureteral reimplantation. Three patients passed stones spontaneously.
RESULTS: In 3 of 4 patients with stones detected before transplantation, the procedure was completed successfully after endoscopic stone removal. Three of 5 patients with transplanted stones required emergency nephrostomy; 1 patient had permanent renal impairment. Three (42.9%) of 7 patients treated with ESWL needed transient nephrostomy; ultimately, all became stone free within a mean 15 days (range 10 to 40). Endoscopic stone removal always resulted in complete clearance without renal impairment. All patients were stone free during a follow-up of 29 months (range 13 to 48).
CONCLUSIONS: Nine (47%) of 19 stones were actually transplanted. Therefore, intraoperative screening by ultrasonography with subsequent endoscopic removal is advisable. Small stones (4 mm or less) may be closely followed up, because they can pass spontaneously. ESWL is the treatment of choice for caliceal stones sized 5 to 15 mm. However, for stones greater than 15 mm or for ureteral stones, antegrade endoscopic procedures seem to be more favorable.