STONE DISEASE

Ex vivo ureteroscopic treatment of calculi in donor kidneys at renal transplantation
Rashid MG, Konnak JW, Wolf JS Jr, Punch JD, Magee JC, Arenas JD, Faerber GJ
Department of Urology, University of Michigan Medical Center, Ann Arbor, 48109, USA
J. Urol. 2004; 171: 58-60

• Purpose: We evaluated the safety and efficacy of ex vivo ureteroscopy (ExURS) as a means of rendering the donated kidney stone-free at live donor renal transplantation.
• Materials and Methods: A total of 10 suitable kidney donors with small, unilateral nonobstructive calculi underwent live donor nephrectomy (8 open flank, 2 hand assisted transperitoneal). Immediately after cold perfusion, ExURS was performed in an iced saline solution. Access to the collecting system was via the ureteral stump. Calculi were either removed with endoscopic baskets and/or completely fragmented with Holmium laser lithotripsy.
• Results: Access to the renal collecting system was technically successful in all cases. A total of 10 stones, ranging in largest diameter from 1 to 8 mm (average 5.2) were visualized. Of the kidneys 6 had solitary stones, 2 had 2 stones and 1 had no stone. Of 10 stones 9 were successfully removed and/or fragmented with an average procedure time of 6.5 minutes (range 3 to 28). Indwelling ureteral stents were placed at transplantation in 5 of 10 kidneys. There were no intra-operative or postoperative ureteral complications. At 1 month after transplant serum creatinine ranged from 0.9 to 2.7 mg/dl (average 1.5). At a mean followup of 33.2 months new stones have not formed in any recipients and at mean 36.4-month followup no new calculi have formed in the remaining kidney of any donors.
• Conclusions: ExURS is a technically feasible means of rendering a stone bearing kidney stone-free without compromising ureteral integrity or renal allograft function.

• Editorial Comment
  Because of the long list of patients awaiting renal transplantation, rules regarding the suitability of live kidney donors have been re-examined in recent years in hopes of expanding the donor pool. In this report, Rashid and colleagues harvested kidneys from donors with small, nonobstructing renal calculi in the donor kidney, then performed ex vivo ureteroscopy to remove the stones prior to transplantation. Although to date, no donor or recipient has had a stone recurrence, the practice of accepting kidney donors who have a systemic renal disease remains controversial.
  With the widespread use of CT for renal imaging, the diagnosis of small, non-obstructing renal calculi has become more common, although the implication of this finding in otherwise asymptomatic patients without a history of stones is unknown. The authors of this paper noted that donors were evaluated metabolically to identify risk factors for stone formation, but they did not mention if donors were excluded based on metabolic abnormalities or if they were treated medically if donor nephrectomy was performed. Although the risk of renal loss associated with stone disease in a solitary kidney is decidedly low, the donor, now with a solitary kidney, requires careful radiographic surveillance, and every stone or symptomatic event requires intervention as for any patient with a solitary kidney. As such, follow-up and care of the donor becomes more involved. While this may constitute an acceptable risk for the donor, we as urologists with a primary concern for the donor must weigh the risk and benefits in our own mind before placing a healthy subject at risk for future renal compromise. As the authors suggest, the long term outcomes of these donors must be carefully followed so that future donors may be properly informed prior to donor nephrectomy.

Dr. Margaret S. Pearle
Associate Professor of Urology
University of Texas Southwestern Med Ctr
Dallas, Texas, USA