A scoping review of outcomes and clinical value in minimally invasive management of graft lithiasis

Background Urolithiasis in the renal allograft (“graft lithiasis”) is uncommon but clinically consequential, since it threatens the function of a single, denervated, heterotopically placed kidney. Minimally invasive treatment [ ureteroscopy, percutaneous nephrolithotomy (PCNL) and shock wave lithotripsy (SWL)] has become the mainstay of management, yet outcome reporting remains centered almost exclusively on the stone-free rate (SFR), with little attention to graft-specific safety, imaging strategy, immunosuppression and functional preservation. This scoping review aimed to map the breadth of outcome reporting in the minimally invasive treatment of graft lithiasis, beyond the SFR. Methods A scoping review was conducted following the Arksey and O’Malley framework and reported per the PRISMA-ScR checklist. PubMed/MEDLINE, Embase and Scopus-indexed literature were searched, supplemented by citation chaining, for studies reporting minimally invasive (ureteroscopic, percutaneous or shock-wave) treatment of graft lithiasis. Data were charted on demographics, immunosuppression, stone characteristics, treatment, imaging, follow-up and outcome. Results Nineteen studies met eligibility; 14 provided extractable outcome data (11 primary clinical reports and three systematic reviews, tabulated separately, including the largest available meta-analysis on this topic: 37 studies, 553 patients, 612 procedures). In a single meta-analysis, pooled stone-free rates at three months ranged from 96% for open surgery (a comparator; 25 procedures) and 95% for antegrade ureteroscopy (20 procedures) to 86% for PCNL, 81% for retrograde ureteroscopy and 75% for SWL. This differs from native-kidney stone disease, where treatment is individualized according to stone and patient factors and retrograde ureteroscopy and SWL are first-line for smaller calculi while PCNL is reserved for larger ones. Immunosuppressive regimens were inconsistently reported, and no study used a validated patient-reported outcome measure or a formal composite endpoint integrating clearance, complications and graft-function preservation. Conclusion Indirect pooled data suggest higher stone-free rates with antegrade approaches than with retrograde ureteroscopy and SWL in graft lithiasis, but this rests on a single meta-analysis and should be considered hypothesis-generating. Reporting of immunosuppression, stone composition, graft function and patient-reported outcomes remains inconsistent and should be prioritized, ideally through a graft-specific composite outcome measure, in future series.