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Allium® metal ureteric stent (AMUS) for ureteral stricture after renal transplantation: The first case report in Taiwan

C. Chen¹, L. Yang¹, J. Li¹, C. Chen¹, S. Wang¹, C. Yang¹, C. Cheng¹

¹Taichung Veterans General Hospital, Urology, Taichung, Taiwan

Introduction:

Ureteral strictures following renal transplantation remain a significant complication, with an incidence of 1–8.3%, adversely affecting graft survival. Traditional management options, including nephrostomy tube, double J stent, and repeated internal dilations, often require frequent interventions and carry risks of infection. Open reconstructive surgery, while the gold standard, is invasive. The Allium® metal ureteric stent (AMUS) is a novel self-expanding device designed for long-term ureteral patency but had not been used in Taiwan for post-transplant ureteral strictures. We report the first case of AMUS placement as an alternative procedure.

Material and methods:

A 35-year-old female with end-stage renal disease underwent a living donor kidney transplant. Despite initial recovery, she developed recurrent urinary tract infections and graft hydronephrosis six months later. Imaging revealed a 2 cm ureteral stricture. Over four years, she underwent multiple double J stent placements, and internal dilations, but her renal function continued to decline, Creatinine 1.68 mg/dL. Given the refractory nature of her condition, AMUS was considered. Under general anesthesia, the patient was positioned in lithotomy. A ureteroscope was introduced into the graft ureteral orifice under guidewire guidance. Fluoroscopic-assisted balloon dilation (15 French, 20 atm, 5 minutes) was performed. A 30 French, 10 cm AMUS was then deployed under fluoroscopic guidance. The procedure lasted 60 minutes with minimal blood loss. The patient was discharged on postoperative day one.

Results:

Postoperative ultrasound showed resolution of hydronephrosis. At one year postoperatively, the patient remained free of hydronephrosis and improved renal function, Creatinine 1.53 mg/dL. AMUS, composed of super-elastic nitinol and a biocompatible polymer coating, prevents tissue ingrowth and encrustation. The advantages include shorter operative time, minimal blood loss, reduced hospitalization, and early return to normal activities. However, potential complications such as vesicoureteral reflux, infection, and stent migration must be considered. While open surgery remains the preferred option for young recipients, AMUS provides an alternative for high-risk or refractory cases.