Yuan HJ et al, 2015: Minimally invasive treatment of renal transplant nephrolithiasis.
Yuan HJ, Yang DD, Cui YS, Men CP, Gao ZL, Shi L, Wu JT.
Department of Urology, Yantai Yuhuangding Hospital Affiliated to Medical College of Qingdao University, NO. 20 East Yuhuangding Road, Yantai, 264000, Shandong Province, China.
PURPOSE: Urolithiasis is a rare complication of renal transplantation, and there is limited evidence to guide treatment. Management of stones in the transplanted kidney can be challenging. We present our experience in treating upper urinary tract (UUT) allograft lithiasis using minimally invasive procedures, with the aim of demonstrating their efficacy and safety in renal transplant recipients.
METHODS: The records of 1615 patients undergoing kidney transplantation and follow-up in our center between August 2000 and July 2014 were reviewed. The mode of presentation, donor type, onset time, immunosuppression protocol, stone character, therapeutic intervention and outcomes of those with UUT allograft lithiasis were recorded. Extracorporeal shock wave lithotripsy (SWL), flexible ureteroscopy (F-URS) and percutaneous nephrolithotomy (PCNL) were used in the management of these calculi. Stone composition was analyzed after the procedure.
RESULTS: Nineteen renal transplant recipients (1.2 %, nine males and ten females) were found to have UUT allograft calculi. Of these, five underwent SWL (26.3 %), four had F-URS combined with lithotomy forceps extraction or holmium laser disruption (21.1 %), six had PNCL (31.6 %), one submitted to F-URS after two failed sessions of SWL (5.3 %), one combined PCNL and F-URS (5.3 %), and two spontaneously of stones (10.5 %). All patients were rendered stone-free with a combination of treatments, and none required a blood transfusion.
CONCLUSIONS: The incidence of calculi in the transplanted kidney is low. Minimally invasive procedures are safe and effective means of removing allograft calculi.
World J Urol. 2015 Apr 2. [Epub ahead of print]
This is a retrospective review of stone treatment in patients with transplanted kidneys. It is learnt from the review that stones were diagnosed in 19 out of 1615 patients with kidney transplants (1.2%). Different treatment modalities for active stone removal were used: 26.3% SWL, 21.1% fURS and 31.6% PNL.
It is not quite clear how and why the different treatment modalities were selected. The comment that “a large proportion of the stones would likely be radiolucent” is poorly supported by the stone analyses. If the authors´ assumption is correct, it means that several of the stones not analysed were composed of uric acid, in addition to those two analytically verified uric acid stones. Combined treatment with SWL and administration of alkali would under such circumstances have been a non-invasive option.
Which kind of lithotripter that was used is not mentioned.That the device delivered shockwaves at a frequency between 500 and 3000 cycles per minute (!) is obviously (and hopefully) a mistake.
Despite some shortcomings in this report, it provides valuable reading, because treatment of stones in transplanted kidneys usually presents a considerable clinical challenge.