Ureteral complications, particularly stenosis and necrosis, represent important challenges following kidney transplant. When endoscopic management fails due to extensive tissue loss, complex surgical reconstruction becomes necessary. We present the case of a 15-year-old female living donor transplant recipient who presented with urosepsis and hydronephrosis shortly after stent removal. After unsuccessful endourological intervention, surgical exploration revealed total ureteral necrosis. We performed a salvage reconstruction using a tapered, isoperistaltic segment of terminal ileum to bridge the defect. At the 3-year follow-up, the patient exhibited excellent graft function with a serum creatinine of 1.1 mg/dL, and imaging confirmed the absence of hydronephrosis. This case demonstrates that ileal ureter interposition serves as a safe and durable salvage technique for managing extensive ureteral defects. This technique offers effective long-term urinary drainage and graft preservation in young recipients when standard reconstructive options are not feasible.

Key words : Ileal ureter, Renal transplantation, Ureteral necrosis, Ureteral reconstruction

Introduction
Kidney transplantation (KT) is widely recognized as the optimal treatment for patients with end-stage renal disease, offering superior survival rates and quality of life compared with dialysis.¹ Despite advancements in surgical techniques, urological complications remain a major source of morbidity, affecting approximately 2.5% to 12.3% of transplant recipients.² Among these, ureteral complications, such as leakage and stenosis, are the most frequent.³ The management of ureteral stenosis depends on the severity and length of the stricture. Endoscopic procedures, such as balloon dilation or stent placement, are often utilized for short, low-grade strictures.¹ However, these minimally invasive attempts may fail in cases involving extensive fibrosis or necrosis. Consequently, open surgical reconstruction is often required for durable results.⁴ Standard reconstructive options typically include ureteroneocystostomy or pyeloureterostomy using the patient’s native ureter.⁵ A major surgical challenge arises when the ureteral defect is too long for standard repair or when the native ureter is unsuitable. In such complex scenarios involving extensive ureteral necrosis, the interposition of an ileal segment serves as a crucial salvage procedure to preserve the graft. This article presents a case of ureteral reconstruction using a reconfigured ileal segment in a 15-year-old girl. The patient developed total ureteral stenosis and necrosis following a living donor KT. We discuss the surgical technique and the successful long-term functional outcome of this complex reconstruction. The patient provided informed consent for the publication of their medical information and treatment details. All efforts were made to maintain patient confidentiality, in line with institutional ethical standards.

Case Report
A 15-year-old female with end-stage renal disease presented for living donor KT. After a complete immunological and preoperative evaluation, she underwent KT with a kidney donated by her mother. Preoperative imaging of the donor confirmed a single renal artery and vein. The donor nephrectomy was performed via a mini-retroperitoneal approach without complications. The graft was transplanted into the recipient’s iliac fossa, and immediate graft function was observed following reperfusion. The postoperative course was uneventful; by postoperative day 6, the serum creatinine level was 0.85 mg/dL, and the estimated glomerular filtration rate was 104 mL/min/1.73 m². The prophylactic ureteral double J stent was removed 2 months postoperatively. Twenty days after stent removal, the patient was readmitted with oliguria and clinical signs of urosepsis. Laboratory evaluation revealed acute kidney injury with a serum creatinine of 3.5 mg/dL and markedly elevated inflammatory markers (C-reactive protein level of 168 mg/L). Although graft ultrasonography indicated normal resistive index values, grade 3 hydronephrosis was detected. An emergency percutaneous antegrade nephrostomy was performed to decompress the system. A concurrent attempt at antegrade ureteral balloon dilation and stent placement was unsuccessful due to high-grade obstruction. Once the acute infection and inflammation had resolved, the patient underwent planned open surgical revision. Intraoperative exploration revealed total stricture and extensive necrosis of the transplant ureter. Given the length of the defect and the patient’s young age, the decision was made to perform an ileal ureter substitution rather than a bladder flap procedure. A 15-cm segment of the terminal ileum was harvested approximately 20 cm proximal to the ileocecal valve, ensuring preservation of the mesenteric blood supply. To approximate the caliber of a native ureter, the ileal segment was tapered longitudinally along the antimesenteric border. The reconstructed segment was interposed in an isoperistaltic configuration; the proximal end was anastomosed to the graft renal pelvis, and the distal end was anastomosed to the bladder (Figure 1). The postoperative double J stent was removed 2 months after the reconstruction. During the follow-up period, the patient maintained stable graft function without significant deterioration. Urinalysis occasionally demonstrated asymptomatic bacteriuria, which was managed conservatively without antibiotic treatment. At the 3-year postoperative follow-up, a noncontrast computed tomography scan showed no evidence of hydronephrosis or other pathological findings (Figure 2). The patient’s renal function remained excellent, with a serum creatinine of 1.1 mg/dL and an estimated glomerular filtration rate of 74 mL/min/1.73 m².

Discussion
This case report highlights the successful management of a complex ureteral complication in an adolescent renal transplant recipient using an ileal ureter interposition. Although ureteral stenosis is a known complication of KT, the extensive necrosis observed in this case necessitated a reconstructive approach beyond standard endourological or surgical techniques. The long-term preservation of graft function in our patient underscores the utility of ileal interposition as a definitive salvage procedure. Urological complications occur in approximately 9% of KT recipients, with ureteral stenosis being the most frequent pathology.¹ Management strategies typically follow a stepwise approach. For short, low-grade strictures, endoscopic interventions such as balloon dilation or stent placement are often the first line of treatment. However, the success of these minimally invasive techniques diminishes significantly in cases of long-segment strictures or ischemic necrosis. As noted by He and colleagues, high-grade strictures (grade 3) involving extensive tissue loss require open surgical reconstruction to achieve patency and prevent graft loss.⁶ When open revision is indicated, the standard technique is often ureteroneocystostomy or, if the native ureter is preserved, pyeloureterostomy.⁵ Studies have shown that utilizing the ipsilateral native ureter is a feasible and safe option for bridging defects.^7,8 However, these methods rely on the availability of healthy ureteral tissue. In scenarios where the ureteral defect is extensive due to necrosis, as observed in our patient, standard reimplantation is impossible. Al-Qaoud and colleagues emphasized that, while minimally invasive options should be reserved for simple strictures, complex cases with failed repairs require durable operative solutions, such as bowel segment interposition.⁴ The use of an ileal segment for ureteral reconstruction is a well-established, albeit less common, procedure in transplantation. Wolters and colleagues reported that ileal interposition is a safe and effective salvage procedure when re-ureterocystostomy is not feasible because of ureteral necrosis.⁹ Our technique involved tapering the ileal segment to approximate the caliber of a native ureter, which facilitates anti-reflux mechanics and effective peristalsis. The 3-year follow-up data showing excellent graft function and no hydronephrosis aligns with the literature, suggesting that operative repair provides durable outcomes for complex strictures.⁴ Furthermore, the patient’s age is a relevant factor. Alberts and colleagues identified recipient age under 18 years as an independent risk factor for surgical revision of ureteral complications.² Managing complications in pediatric and adolescent patients requires meticulous planning to ensure longevity of the graft. Although robotic-assisted reconstruction is emerging as a safe alternative with high success rates,³ the complexity of creating an ileal ureter often necessitates an open approach to ensure precise anastomosis and preservation of the mesenteric blood supply. In conclusion, despite native urinary tract reconstruction remaining as the gold standard, ileal ureter interposition has been shown as a vital salvage technique for extensive ureteral necrosis. This case demonstrated that, with careful surgical technique, including tapering and isoperistaltic placement, ileal reconstruction provides excellent long-term functional outcomes in young transplant recipients.