Ureteroscopy for renal allograft lithiasis: institutional experience and global insights from a systematic review

Renal allograft lithiasis (RAL) is a rare but potentially serious complication following kidney transplantation. Traditionally, ureteroscopy (URS) has been considered a second-line treatment for stones <15 mm, typically after failed extracorporeal shock wave lithotripsy (ESWL), due to concerns over challenging ureteral access. This study reviews Singapore General Hospital (SGH)'s experience and compares outcomes with published literature to evaluate efficacy and safety.

Retrospective review was conducted on RAL cases treated with URS at SGH from January 2015 to December 2023. Data collected included demographics, end-stage renal failure etiology, preoperative biochemistry, stone characteristics, and surgical details. Stone-free status and complications were assessed. Additionally, a systematic literature review was performed using five databases (PubMed, Embase, Web of Science, SCOPUS, Cochrane Library) from inception up to August 13, 2023. We included all primary studies with no restriction on study design, published in English, including conference abstracts and excluded articles on ex-vivo or pre-transplant URS. Risk of bias assessment was performed using Joanna Briggs Institute Critical Appraisal Tools.

Five URS procedures were performed at SGH for RAL during the study period, yielding a stone-free rate (SFR) of 71.4%. One case involved an encrusted double-J (DJ) stent. The systematic review included 30 studies (10 case reports, 20 case series) totaling 145 URS procedures. The overall SFR was 82.3%. Thirteen complications (9.0%) were reported, including ureteral perforation (n=3), urinary tract infections (n=3), and nephrocutaneous fistula (n=2). No graft loss was reported. These rates are comparable to those seen in non-transplant URS.

URS appears to be a safe and effective treatment for RAL, with outcomes comparable to non-transplant populations. Increasing evidence supports URS as a first-line option in select transplant patients. The current evidence is limited by small case numbers, retrospective study designs, and lack of standardisation in defining and assessing stone-free outcomes.