Therapy-Refractory Matrix Staghorn in a Kidney Transplant Recipient: Endoscopic Percutaneous Morcellation as a Novel...

Urolithiasis of transplant kidneys usually encompasses a challenging clinical situation due to specific anatomical conditions and the patients' immunological status. In this case report, we describe the treatment of a rare Proteus mirabilis matrix staghorn stone applying percutaneous nephrolithotomy in combination with matrix stone extraction by morcellation while utilizing endo-urological equipment designed for transurethral prostate surgery. We present the case of a 44-year-old Caucasian woman who had undergone a post-mortal kidney transplant at age 37. After recurrent urinary tract infections, symptomatic obstructions of the transplant ureter, and multiple surgical interventions (73 Double-J stent and nephrostomy placements and three ureter re-implantations), permanent percutaneous nephrostomy drainage was established 6 years after her kidney transplantation. The patient was referred to our department due to recurrent dysfunction of the nephrostomy tube caused by blockage due to stone-matrix material and a staghorn calculus in the transplant kidney's collecting system. Microbiological examination of the stone material retrieved from the nephrostomy tube revealed massive P. mirabilis contamination. In this work, we present a novel percutaneous technique of matrix stone removal by relying on endoscopic equipment usually employed during prostate surgery by urologists. Percutaneous matrix stone morcellation is a technically challenging but feasible method that might be considered as a salvage treatment strategy in situations described earlier and in highly selective cases. However, for this extremely rare stone entity and individual clinical presentations, matrix stone morcellation seems to be a reasonable alternative before considering more radical interventions such as open nephrolithotomy. Selection criteria are a very soft stone, large-caliber percutaneous access to the collecting system, and enough space in the collecting system to execute morcellation.