Outcomes of Percutaneous Nephrolithotomy in Kidney Transplant Recipients: Results from a Multicenter Study by the Spanish Urology Association's Renal Transplant Group.

Introduction: Stone disease amongst kidney transplant recipients (KTR) may not only lead to significant morbidity but also compromise graft function. In this context, percutaneous nephrolithotomy (PCNL) has emerged as a fundamental minimally invasive surgical technique for the treatment of kidney stones in KTR. The aim of this study is to evaluate the outcomes of PCNL in KTR in a nationwide series, encompassing operative results, stone-free rate (SFR), stone composition and renal graft function.

Materials & methods: Retrospective data from five Spanish tertiary hospitals was analysed. All KTR that underwent PCNL between January 2005 and August 2024 were included in the study. Stone characteristics, postoperative complications, and surgical outcomes were evaluated.

Results: The study included 39 KTR, median age 59 (32-82) years, predominantly male (71.8%). Most KTR received grafts from cadaveric donors (n = 35). Even though stone diagnosis was often incidental (64.1%), 74.3% of KTR experienced stone-related events before surgery, such as acute kidney failure (53.8%) and sepsis (15.4%). Diagnosis occurred after a median of 53 (0-264) months post-transplant. Preoperative nephrostomy insertion was common (59.0%), and 48.7% of KTR had positive urine cultures. Median stone size was 14 (5-50) mm with 53.8% of KTR having multiple stones. Median stone density was 720 (130-1770) HU. Overall complication rate after PCNL was 10.2%: 2 patients presented with urinary septic shock, 1 patient experienced puncture site bleeding requiring embolization and 1 haematuria accompanied by acute renal failure. Stone-free rate was 82.0% in the first procedure, with secondary treatments being successful when needed. The most frequent stone composition was calcium oxalate monohydrate (55.2%).

Conclusions: In our experience, PCNL is an effective and safe technique for addressing nephrolithiasis in KTR. SFR and complication rates may be comparable to those reported in PCNL performed in native kidneys. Furthermore, patients tend to benefit from surgical care in high-volume centres that possess dedicated expertise in both KT and endourology.