• cost‐effectiveness
• double‐J stents
• malignant ureteric obstruction
• metallic stents

• MUO
• Malignant ureteral obstruction
• Metallic stent
• Resonance
• Ureteric stent

• Humans
• Ureter/surgery
• Ureteral Obstruction/etiology
• Ureteral Obstruction/surgery
• Longitudinal Studies
• Quality of Life
• Retrospective Studies
• Stents
• Polymers
• Neoplasms

• Anti-Encrustation
• Anti-infective coating
• Antibacterial
• Catheter
• Ureteric stent

Refractory non-malignant ureterostenosis is challenging to treat. The experience to treat the stenosis primarily cause by retroperitoneal fibrosis with the Resonance and Allium metallic stent is still limited. We aim to evaluate the efficacy and safety of these two stents and provide alternative treatment options.

A retrospective study was conducted for patients with non-malignant ureterostenosis and treated with the Resonance and Allium stents from March 2011 to September 2020 in our department. The efficacy was evaluated by the change of serum creatinine, glomerular filtration rate (GFR), the proportion of GFR of the affected side and hydronephrosis grade. The safety was evaluated by postoperative presence of moderate or severe overactive bladder (OAB), recurrent urinary infection, pain, stent displacement, encrustation and re-obstruction.

33 patients were eligible for the study, including 18 cases treated by the Resonance stents and 15 patients treated by the Allium stents. The patients of two groups had similar age and gender proportion. The cause of ureterostenosis was mainly retroperitoneal fibrosis in both groups but the Resonance group had more idiopathic cases. Follow-up time was significantly longer in the Resonance group than the Allium group (36.2 ± 24.0 vs 9.4 ± 5.0 months, p < 0.001). Both groups showed improvement or maintenance of serum creatinine level, GFR, the GFR proportion of the affected side and hydronephrosis grade after treatment. The Resonance group presented significant higher incidence of moderate or severe OAB, recurrent urinary infection and pain, while the Allium group showed significant more cases of re-obstruction.

Both the Resonance and Allium stent can relieve the non-malignant refractory ureterostenosis effectively. The Resonance stent may cause more irritable symptoms while the Allium stent may have a higher rate of re-obstruction. The long term efficacy and safety of the Allium stent in treating non-malignant refractory ureterostenosis requires further study.

The online version contains supplementary material available at 10.1186/s12894-021-00815-6.

• Allium stent
• Efficacy
• Resonance stent
• Retroperitoneal fibrosis
• Safety
• Ureterostenosis

Retroperitoneal fibrosis is an exceptionally rare disease characterized by proliferation of fibrous tissue and inflammation in the retroperitoneum. It features many symptoms in the kidneys and in other organs and usually leads to ureteral obstruction.

Here we present 9 consecutive cases of idiopathic retroperitoneal fibrosis (IRPF) in patients who presented to the Department of Nephrology or Department of Rheumatology, Xuanwu Hospital, Capital Medical University, Beijing, China, between January 2012 and June 2017 with ureteral obstruction due to external compression of the ureter that led to hydronephrosis and kidney dysfunction. Computed tomography imaging was used to identify hydronephrosis and ureteral obstruction and to evaluate kidney function. Each patient was diagnosed with IRPF based on clinical observation and computed tomography examination results. To restore kidney function, a retrograde metallic stent was placed in the ureter under X-ray guidance 2 d after each patient’s admission. No perioperative complications occurred in any patient, but postoperative complications occurred in two patients as follows: Patient 2 had stent migration and repeated metallic stent infections that resolved with treatment; and patient 4 had postoperative hematuria because he resumed normal activities too soon after stent placement (contrary to instruction). Placement of the metallic ureteral stents provided relief from ureteral obstruction and restored kidney function in all patients.

Our 9-case series underscores the utility and efficacy of applying the Resonance^® metallic ureteral stent to treat ureteral obstruction in patients with IRPF. For all retroperitoneal fibrosis cases in our series, ureteral stents provided effective relief and were shown to reduce the incidence rate of perioperative and postoperative complications.

• Retroperitoneal fibrosis
• Metallic ureteral stent
• Ureteral obstruction
• Computed tomography
• Kidney function
• Plastic stent
• Case report

To study the outcomes and experiences of using metallic stents in treating patients with malignant ureteral obstruction (MUO), we examined the effects of metallic ureteral stenting using the Cook Resonance® stent in the treatment of MUO.

All patients who had a Resonance metallic stent inserted between April 2015 and March 2018 at one of multiple facilities were prospectively observed with a 1-year follow-up. The primary outcome was the patency rate of the metallic ureteral stent. The secondary outcomes included the complications (e.g., infection and fever).

Although stent insertion was attempted in 50 patients, the stent could not be inserted as a ureteral stent in three patients due to severe ureteral stricture, and one ureteral cancer patient was excluded from the analysis. The remaining 46 patients’ median age was 67 years (range 28–85 years) (16 males, 30 females). Twenty-four patients died during the study; their median survival time was 226 days. The median follow-up period for the censored patients was 355 days (range 16–372 days), and just seven patients were still alive without Resonance failure > 1 year later. The women’s IPSS scores tended to be lower than those of the men. Regarding the OABSS score, although the women’s total score tended to be low, the difference between the men’s and women’s scores was nonsignificant. The bacteria detected from urine culture after stent insertion were more gram-positive than gram-negative.

Metallic ureteric stenting using the Resonance stent is safe and effective for treating MUO. Subjective symptoms were relatively less in the female patients.

• Malignant ureteral obstruction
• Metal stent
• Metallic ureteric stenting
• Resonance stent
• Ureteral stent

• Resonance metallic stent
• malignant ureteral obstruction
• metallic stent
• ureteral obstruction

• Adult
• Aged
• Aged, 80 and over
• Female
• Humans
• Kaplan-Meier Estimate
• Male
• Metals
• Middle Aged
• Polymers
• Prosthesis Design
• Retrospective Studies
• Stents
• Ureteral Obstruction/surgery

• Resonance(®) stent
• Transplant kidney
• Ureteric obstruction

• metallic
• obstruction
• resonance
• stent
• ureteral