BERKELEY, CA (UroToday.com) - In this article, we discuss the management options available for treatment of urolithiasis in renal grafts harboring calculi. It is necessary to render these grafts free of stones prior to engrafting. The importance of this aspect of renal transplantation deserves attention due to two issues.
First, the number of chronic kidney disease (CKD) patients requiring renal transplant is exponentially increasing, however, the living donor pool is not increasing proportionally. This fact assumes importance in a scenario where cadaver organ retrieval is not common. The marginal donors, defined as donors with hypertension, diabetes, and or urolithiasis help in filling this “void.”
The second aspect is, due to the recent trend of performing computed tomographic angiography as a part of renal donor work up, increasing numbers of donors with non-obstructing, unilateral, asymptomatic stones are diagnosed during donor work up. These potential donors are likely to be rejected by centers due to concerns regarding management of stones in the graft and the risk of recurrence, despite satisfying other Amsterdam criteria for donor selection. Endourologic techniques which include ex vivo or “on bench” endourologic manipulations (such as ureteroscopy (URS) or pyelolthotomy (Pyl), retrograde intrarenal surgery (RIRS), extracorporeal shock-wave lithotripsy (ESWL)) form the cornerstone for rendering these grafts stone free to enable successful engrafting. It is imperative that there should be a framework of algorithms and techniques that clear the stones from the grafts in an effective and safe manner. We have attempted to put forth a treatment algorithm for managing these patients.
Twelve renal donors were included in the analysis. The management options were pretransplant ESWL, RIRS, ex vivo interventions, or observation. In the pre-transplant ESWL group, an average of 740 shocks (600-1500) were given. The power was not ramped up beyond 12 Kv, and the frequency was kept at 60 per minute. Ex vivo URS was performed on bench with 6F pediatric cystoscope, while in the ex vivo Pyl, a 12F nephroscope was introduced via a pyelotomy, and stones were retrieved, intact, with a dormia basket. A postoperative ultrasound at one month revealed complete clearance of stones in all 12 donors, except one. At a mean follow up of 36 months (10-58) there was no stone recurrence in any donor or recipient. The recipient outcome at follow up was encouraging. The bench procedures added 20 minutes of time after onset of cold ischemia. As the ex vivo procedures were done after the onset of cold ischemia, they did not affect the overall outcome.
As a dictum, the “better kidney was left with the donor.” The decision to treat the stone pre-transplant or post transplant was taken after assessing the CT findings. It was imperative that the patient did not have any metabolic abnormality prior to acceptance as a donor. Hard stones with higher Hounsfield units (more than 1 200) were preferably tackled with ex vivo (URS or Pyl) endoscopic intervention or preoperative RIRS. The choice between the two was decided by the pelvicalyceal anatomy. All stones that were soft (less than 1 200) were tackled with pre-transplant ESWL. Stones less than 4 mm in size were treated with double-J stenting and close observation.
The concerns regarding on-bench ex vivo intervention include the possibility of postoperative ureteric strictures and the need for expertise and an armamentarium to tackle these calculi. The follow up was based on serum creatinine estimation and sonography. None of the patients (including those who underwent ex vivo intervention) showed any graft hydronephrosis and /or deranged graft function. The limitations of our study include a retrospective design and lack of “long term” stone-recurrence data. This article could help in designing multicentre large scale studies to address this problem.
Arvind Ganpule, MS, DNB as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Urology, Muljibhai Patel Urological Hospital, Nadiad, India