A Prospective Randomized Comparison of a Covered Metallic Ureteral Stent and a Double-J Stent for Malignant Ureteral Obstruction

Malignant upper urinary tract obstruction in cancer patients: A systematic review

Objective

To systematically summarise the current clinical evidence for de novo malignant upper urinary tract obstruction treatment with a focus on standards of reporting, patient outcomes and future research needs.

Methods

This review protocol was published via PROSPERO (CRD42022341588). OVID MEDLINE (R), EMBASE, Cochrane Central Register of Controlled Trials-CENTRAL were searched up to June 2022 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses. Prospective and retrospective studies were included.

Results

Of 941 articles identified, 82 with 8796 patients were eligible for inclusion.Most studies in the published literature are retrospective and investigate heterogenous malignancies. Percutaneous nephrostomy and ureteric stenting are the most studied interventions. Few studies describe the outcomes from no intervention or investigate patient perspectives. Overall reported median survival after intervention was around 11.7 months. A lack of standardised reporting of outcomes was evident.

Conclusions

Malignant upper urinary tract obstruction is an important clinical condition affecting patients globally. Overall survival after intervention appears poor however the current evidence base has significant limitations due to studies of low methodological quality and the lack of a standardised framework for reporting outcomes.We have provided a pragmatic framework for future studies based on the review to ensure a uniform methodology is utilised moving forward.

A Silicone-Covered Self-Expanding Metal Stent with Anti-migration Features for Treating Malignant Ureteral Obstruction

PURPOSE

To evaluate the effectiveness and safety of the Urexel stent for treating malignant ureteral obstruction (MUO).

MATERIALS AND METHODS

This retrospective study included 129 patients (mean age: 57.9 ± 11.8 years; men: n = 64, 49.6%; ureteral units [UUs]: N = 175) who underwent Urexel stent placement to treat MUO between March 2013 and April 2021. The Urexel stent is a fully covered self-expanding metal stent. To reduce stent migration, the proximal end of the stent has an additional layer of stent mesh and is flared mildly.

RESULTS

Eighty-three patients (64.3%) had unilateral MUO (right side: n = 47, 36.4%; left side: n = 36, 27.9%), and 46 patients (35.7%) had bilateral MUO. Successful Urexel stent placement after successful guidewire passage of the obstructed ureteral segment was achieved in 172 UUs, rendering a technical success rate of 98.3%. Stent malfunction occurred in 37 UUs (21.4%) during follow-up, including tumor overgrowth (n = 29), tumor ingrowth (n = 3), stent migration (n = 3), and stent collapse (n = 2). A total of 120 patients (93.0%) died during a median follow-up of 4.1 months (range: 0.2 - 33.5). The median survival of the patients was 4.4 months (interquartile range [IQR] 2.0 - 8.8). The median malfunction-free survival of the patients was 3.6 months (IQR: 1.6 - 7.9). Fifteen grade 3 or higher complications occurred in 14 patients (10.9%), including flank pain (n = 10), gross hematuria (n = 4), and dysuria (n = 1).

CONCLUSION

Urexel stent placement may be effective and safe for treating MUO.

New Stent Technologies

Ureteral stents are an indispensable part of any (endo-) urologic practice. Despite the widely demonstrated advantages of stents, they also carry a considerable risk of side effects and complications, such as urinary symptoms, pain, hematuria, decreased quality of life, stent-related infection, and encrustation. Multiple pathways in preventing or mitigating these side effects and complications and improving stent efficacy have been and are being investigated, including stent architecture and design, biomaterials, and coatings. This article provides an update on currently researched and available stents as well as future perspectives.

Technical Notes on Fluoroscopy-Guided Removal of Metallic Ureteral Stents

This manuscript describes various techniques for fluoroscopy-guided removal of metallic ureteral stents. Fifteen patients underwent 17 fluoroscopy-guided removal procedures of 22 metallic ureteral stents. The simple or modified snare or retrieval hook technique was primarily used for antegrade access, whereas the loop snare technique was primarily used for retrograde access. Overall 64.7% of the stents were removed using the initial retrieval technique, and 82.4% were removed using an adjunct technique. Procedure-related complications included hematuria in 41.2% of cases and resolved spontaneously in all patients. Fluoroscopy-guided removal of metallic ureteral stents is safe and effective.

Comparison of a covered metallic ureteral stent and a double-J stent for malignant ureteral obstruction in advanced gastric cancer

AIM

To compare the patency and safety of covered metallic stents (CMS) and the double-J stent (DJS) for treating malignant ureteral obstruction (MUO) in advanced gastric cancer (AGC).

MATERIALS AND METHODS

Between 2016 and 2018, the medical records of 61 patients (84 ureters; CMS, 39 patients, 54 ureters; DJS, 22 patients, 30 ureters) with MUO caused by AGC were reviewed retrospectively. The Kaplan-Meier method and log-rank test were used to evaluate differences of primary or assisted primary patency between groups. Cox regression was conducted separately for early (within 7 days) and late (after 7 days) primary patency.

RESULTS

Technical success of CMS placement was 100% (54/54) and 96.8% (29/30) for DJS (p=0.357). The cumulative stent patency rates at 1, 3, 6, and 12 months were 77%, 74%, 70%, and 70%, in the CMS group and 72%, 60%, 53%, and 26%, in the DJS group. Apart from the period within 7 days (p=0.784), primary patency was consistently higher in the CMS group when compared to the DJS group over the entire follow-up period (p=0.034). Assisted primary patency was consistently higher in the CMS group than in the DJS group over the entire follow-up period (p=0.001). The CMS group was more likely to have complications than the DJS group (48.1% versus 16.7%, p=0.004). Complications were minor, self-limiting events such as haematuria/haematoma.

CONCLUSION

CMS had better late patency and assisted primary patency than DJS. Procedure-related minor complications more frequently occurred with CMS.

Temporary Covered Metallic Ureteral Stent Placement for Ureteral Strictures following Kidney Transplantation: Experience in 8 Patients

This brief report presents 8 patients with silicone-covered metallic stent placement for ureteral strictures refractory to double-J stent placement, following kidney transplantation. Stent removal was successfully performed in 7 patients via antegrade (n = 4) or retrograde (n = 3) access 6 weeks to 6 months after stenting for elective removal (6-month interval, n = 3), urothelial hyperplasia (n = 2), or stent migration (n = 2), and their mean primary ureteral patency after stent removal was 15.4 months (range, 2-27 months). Hematuria (n = 2) and pain (n = 3) occurred, but resolved within 1 week. One stent was removed during reconstructive surgery. During follow-up of mean 22.6 months after stent removal, ureteral strictures recurred in 2 patients.

Stenting Using the Rendezvous Technique for Postoperative Ureteral Complications in Cancer Patients

PURPOSE

This study aimed to retrospectively evaluate the safety and efficacy of ureteral stent placement using the rendezvous technique for the treatment of postoperative ureteral complications in cancer patients.

MATERIALS AND METHODS

From January 2005 to April 2015, 19 patients (2 men and 17 women; median age, 59; range, 42-79 years old) with unilateral ureteral lesions (ureteral leakages in 6, strictures in 4, and both in 9) underwent ureteral stent placement using the rendezvous technique. Percutaneous nephrostomy was performed, and stent placement was attempted via antegrade and retrograde approaches. The technical success, procedure-related complications, and clinical success were retrospectively analyzed.

RESULTS

The median follow-up period was 29.8 months (range, 0.3-116.5 months). The ureteral stent placement was successful in 17 out of 19 patients (89.5%). Double J ureteral stent was used in 6 patients, and straight catheter as an internal-external nephro-ureteral stent was used in 11 patients. The rendezvous technique was used in the retroperitoneal space and urinary tract in 6 and 11 patients, respectively. No major complications related to the rendezvous technique occurred. Finally, 4 patients achieved stent-free condition (21.1%), and periodic stent exchange was continued in 9 (47.4%). However, permanent external drainage and surgical reconstruction were needed in 4 (21.1%) and 2 (10.5%) patients, respectively. The final clinical success rate was 68.4% (13 out of 19 patients).

CONCLUSION

Ureteral stent placement using the rendezvous technique for the treatment of postoperative ureteral complications in cancer patients is safe and may be alternative to permanent external drainage and invasive surgical reconstruction.

LEVEL OF EVIDENCE

Level 4, Case series.

Placement of double-J stent in patients with malignant ureteral obstruction: antegrade or retrograde approach?

AIM

To determine whether antegrade or retrograde methods should be preferred for double-J stent placement in patients with malignant ureteral obstruction (MUO).

MATERIAL AND METHODS

The medical records of patients treated for MUO in the Urology and Interventional Radiology Clinic, Konya Training and Research Hospital, were reviewed retrospectively. Patients with benign aetiology were excluded from the study. Reports of the procedures, ultrasonography findings, computed tomography (CT), angiography, and pyelography images and the follow-up records of patients with MUO were assessed. A total of 111 patients and 114 ureteral stenting treatments were included in the study; 63 (55.3%) were operated on using the antegrade ureteral stenting (AUS) method, whereas 51 (44.7%) were operated on using the retrograde ureteral stenting (RUS), method, and the characteristics of these groups were evaluated. The presence of hydroureteronephrosis and ureteral tortuosity were determined.

RESULTS

Overall success rates were found to be 95.2% using the AUS method and 47.1% using the RUS method. The technical success of the antegrade method was significantly higher in patients with or without tortuosity (respectively: p=0.005, Z shape p=0.001, pigtail shape p=0.035″). The technical success of the antegrade method was significantly higher in patients with hydroureteronephrosis (p=0.001).

CONCLUSION

The AUS technique should be the first choice for double-J stent placement in patients with MUO.

Malignant ureteral obstruction: experience and comparative analysis of metallic versus ordinary polymer ureteral stents

BACKGROUND

To study the outcome and experience of using metallic stents in treating patients with malignant ureteral obstruction (MUO).

METHODS

Seventy-six patients with MUO were assigned to the metallic stent group (MSG) or the ordinary polymer stent group (OPSG) according to the different materials. The success rate of the operation, duration of operation, patency rate serum creatinine values ,postoperative complications and QOL scores were compared between the two groups.

RESULTS

In the OPSG and MSG, the success rates of the operation were 95.5% and 96.9%, respectively, and the durations of the operation were 20.6 ± 2.2 min and 50.9 ± 10.3 min (P < 0.01), respectively. There was no significant difference between the groups in serum creatinine values at 3 days after the operation (P > 0.05); however, the creatinine values at 3 days after the operation decreased significantly compared with those before the operation (P < 0.01). In the OPSG, there was no significant difference in creatinine values between 3 days and 6 months after operation, while the creatinine values 1 year after operation were increased significantly compared to those at 3 days after the operation (P < 0.05). In the MSG, there was no significant difference among creatinine values at different intervals (P > 0.05). The total rate of post-procedural complication was lower in the MSG than that in the OPSG(P < 0.05). There was no significant difference in the QOL score between the two groups before the operation (P > 0.05); however, the QOL scores at 6 months and 1 year after the operation were higher in the MSG than that in the OPSG(P < 0.05). In the MSG, there was no significant difference in the QOL score between preoperation and 6 months after surgery. Similarly, there was also no difference in the QOL score between 6 months after surgery and 1 year after surgery(P > 0.05). On the contrary, the differences of QOL score in the OPSG group were much significant between disparate time intervals (P < 0.05).

CONCLUSIONS

For patients with MUO who require long-term retention of the stent, metallic stents with longer indwelling time are superior to ordinary polymeric stents.