Objective  To evaluate the safety and efficacy of Allium covered metallic ureteral stent placement as a maintenance therapeutic strategy for ureteral stricture secondary to idiopathic retroperitoneal fibrosis (iRPF) through a multicenter retrospective observational study.

Methods  A retrospective analysis was conducted on clinical data of patients diagnosed with iRPF-induced ureteral stricture, treated at Peking University People's Hospital, Aerospace Center Hospital, and Beijing Changping District Hospital of Integrated Traditional Chinese and Western Medicine between June 2020 and June 2024. All patients underwent Allium covered metallic ureteral stent implantation. Regular postoperative follow-ups were performed to assess technical success rates, stent patency rates, renal function (serum creatinine levels), improvement in the degree of hydronephrosis, and associated complications.

Results  In this study, a total of 45 stents were implanted in 27 patients (40  renal units), achieving a technical success rate of 100%. The median follow-up duration was 44 months. At the final follow-up, the median serum creatinine level decreased significantly from 121.8 μmol/L preoperatively to 100.0 μmol/L (P<0.001). The median renal pelvic width also exhibited a significant reduction from 1.7 cm preoperatively to 1.0 cm (P<0.001). During the follow-up period, the primary complication was stent migration (1 case, 3.7%), which was successfully managed endoscopically. The primary patency rate was 97.5%, and the secondary patency rate following re-intervention was 100%.

Conclusion  The implantation of Allium covered metallic ureteral stents constitutes a safe and effective minimally invasive therapeutic modality for managing ureteral stricture caused by iRPF. It significantly improves renal function, relieves obstruction, and demonstrates favorable long-term patency outcomes. Stent migration represents the principal complication; however, its incidence is low and it can be successfully addressed through endoscopic intervention.

1.Vaglio A, Salvarani C, Buzio C. Retroperitoneal fibrosis[J]. Lancet, 2006, 367(9506): 241-251. DOI: 10.1016/S0140-6736(06)68035-5.

2.Steimer A, Becker MO. Treatment approaches for idiopathic retroperitoneal fibrosis: a systematic review with Meta-analysis[J]. BMC Rheumatol, 2025, 9(1): 12. DOI: 10.1186/s41927-024-00445-z.

3.Carey C, Gurumurthy G, Napier-Hemy R, et al. A review of the current treatment methods for retroperitoneal fibrosis with obstructive uropathy[J]. BJUI Compass, 2024, 5(8): 721-731. DOI: 10.1002/bco2.371.

4.Harraz AM, EL-Nahas AR, Zahran MH, et al. Would the indwelling internal ureteral stent influence renal function despite relief of benign ureteral obstruction?[J] J Endourol, 2014, 28(2): 243-247. DOI: 10.1089/end.2013.0521.

5.Huang Z, Liu Y, Xiao Y, et al. Idiopathic retroperitoneal fibrosis-related hydronephrosis: evaluation of comprehensive management and prediction of inflammatory markers for stent-free outcomes[J]. Int J Gen Med, 2025, 18: 113-121. DOI: 10.2147/IJGM.S490245.

6.Khoo CC, Abboudi H, Cartwright R, et al. Metallic ureteric stents in malignant ureteric obstruction: a systematic review[J]. Urology. 2018, 118: 12-20. DOI: 10.1016/j.urology.2018.01.019.

7.Gao W, Xing T, Ou T. The Resonance and the Allium ureteral stents in the treatment of non-malignant refractory ureterostenosis[J]. BMC Urol, 2021, 21(1): 53. DOI: 10.1186/s12894-021-00815-6.

8.Bian X, Hu H, Tian C, et al. Comparison of different segmental metal ureteral stents as maintenance therapy across different years in ureteral stricture management: a systematic review and Meta-analysis[J]. Int J Surg, 2025, 111(7): 4746-4755. DOI: 10.1097/JS9.0000000000002384.

9.Zhao J, Li J, Zhang Z. Long-term outcomes and predictors of a large cohort of idiopathic retroperitoneal fibrosis patients: a retrospective study[J]. Scand J Rheumatol, 2019, 48(3): 239-245. DOI: 10.1080/03009742.2018.1497700.

10.Gao X, Chen J, Chen G, et al. Self-expanding metal ureteral stent for treating ureteral strictures: 3-year follow-up results from 310 cases[J]. Int J Surg, 2025, 111(8): 4986-4992. DOI: 10.1097/JS9.0000000000002578.

11.Chen HY, Sinha AK, Choy JS, et al. Mis-sizing of stent promotes intimal hyperplasia: impact of endothelial shear and intramural stress[J]. Am J Physiol Heart Circ Physiol, 2011, 301(6): H2254-H2263. DOI: 10.1152/ajpheart.00240.2011.

12.Gómez García I, Sánchez Castaño A, Romero Molina M, et al. Retroperitoneal fibrosis: single-centre experience from 1992 to 2010, current status of knowledge and review of the international literature[J]. Scand J Urol, 2013, 47(5): 370-377. DOI: 10.3109/00365599.2012.747564.

13.Gao W, Ou TW, Cui X, et al. Metallic ureteral stent in restoring kidney function: nine case reports[J]. World J Clin Cases, 2020, 8(13): 2841-2848. DOI: 10.12998/wjcc.v8.i13.2841.