Antegrade and Retrograde Endoscopic Approaches for Managing Obstructing Ureteral Calculi in Renal Transplant Patients: An Illustrative Case Series

Abstract

Purpose: To demonstrate the various antegrade and retrograde endourologic approaches that may be required for effectively treating kidney transplant recipients presenting with ureteral obstruction caused by urolithiasis. Materials and Methods: We prospectively evaluated endoscopic management techniques of renal transplant recipients referred to a national kidney transplant center with obstructing transplant ureteral calculi for a 12-month period (April 2019-April 2020). Results: Four kidney transplant recipients presented with ureteral obstruction caused by urolithiasis and the mean age was 66.6 (range: 62-71) years. The mean duration from renal transplantation was 16 (range: 6-25) years. Three patients presented with acute urosepsis and one patient presented with malaise and recurrent urinary tract infections. Two patients were definitively treated with percutaneous antegrade flexible ureteroscopic lithotripsy through a 16F minipercutaneous nephrolithotomy sheath. Two patients were definitively treated with retrograde flexible ureteroscopy (7F single-use disposable ureteroscope) and laser lithotripsy. Full stone clearance was achieved in all four patients and no perioperative complications occurred. Conclusion: Management of ureteral calculi in renal transplant recipients is challenging. A multimodal approach involving antegrade and retrograde endoscopic techniques may be required to achieve full stone clearance.

Keywords: kidney transplant; urinary tract calculi; urinary tract calculi in transplant ureters; urolithiasis.

FIG. 1.

Case 1: 15 mm obstructing stone in midureter of transplant kidney. (A) Axial image showing calculus in the midureter of the transplant kidney (arrow). (B) Coronal image showing calculus in the midureter of the transplant kidney (arrow) with associated hydroureteronephrosis. (C) Two wires were passed preoperatively through the nephrostomy to the bladder to aid retrograde passage of the ureteroscope to the level of the calculus (arrow) where ∼50% was lasered (see D). (D) A percutaneous nephrostomy tube was inserted to provide antegrade access to the residual stone burden. (E) Supine PAUL through a 16F minipercutaneous nephrolithotomy (mini-PCNL sheath) was performed to access and fragment the remaining stone using holmium:YAG laser (10 Hz and 1 J with a 7F flexible ureteroscope (Lithovue©; Boston Scientific) (arrow). (F) Final screening image shows complete stone clearance (arrow) with antegrade ureteral stent and nephrostomy in situ. PAUL, percutaneous antegrade flexible ureteroscopic lithotripsy.

FIG. 2.

Case 2: distal ureteral calculi at the level of a long-standing anastomotic stricture. (A) Axial image showing calculi within the distal transplant ureter at the level of anastomotic stricture (arrow). (B) Antegrade nephrostogram showing obstruction to the flow of contrast at the level of the ureterovesical anastomosis secondary to calculi at the level of a long-standing ischemic stricture (arrow). (C) Antegrade flexible ureteroscopy (arrow) with extraction of distal ureteral calculi and free drainage of contrast into the urinary bladder on antegrade nephrostogram.

FIG. 3.

Case 3: 8 mm obstructing midureteral calculus in en bloc kidney transplant. (A) En bloc pediatric renal transplantation involves transplantation of two kidneys from a deceased pediatric donor, en bloc into an adult recipient. The en bloc specimen is initially prepared on the back table with dissection of the ureters and vessels, oversewing of the superior ends of the great vessels and a spatulated Wallace anastomosis of the ureters. (B) Axial image of obstructing stone in midureter of the transplant kidney (arrow). (C) Coronal image of obstructing stone in midureter of the transplant kidney (arrow). (D) Retrograde FURS with full stone clearance. FURS, flexible ureterorenoscopy.

FIG. 4.

Case 4: 12 mm obstructing calculus in distal ureter of transplant kidney. (A) Axial image showing a 12-mm stone in the transplant ureter (arrow). (B) Retrograde FURS (arrow) with full stone clearance.