Complications After Polymeric and Metallic Ureteral Stent Placements Including Three Types of Fistula

Efficacy and Safety of Self-Expandable Covered Metallic Stents for Benign and Malignant Ureteral Obstructions: A Long-Term Retrospective Study

Background and Objectives: This study evaluated the safety and efficacy of long-term indwelling self-expandable covered metallic stents (UVENTA; Taewoong Medical Co., Ltd., Seoul, Republic of Korea) used to manage benign and malignant ureteral strictures. Materials and Methods: We retrospectively identified and analyzed the medical records of all patients who underwent metallic stent insertion at our institution since September 2012. Additionally, we evaluated the technical and clinical success rates and complications of patients who underwent follow-up for more than 36 months. Results: A total of 25 patients underwent metallic stent insertion for ureteral obstructions at our institution. Among them, 18 underwent follow-up for more than 36 months. A total of 21 ureters (15 unilateral and 3 bilateral) were ultimately included in this study. Metallic stents were successfully placed in all ureters using a retrograde approach, with a technical success rate of 100%. The mean follow-up duration was 58.6 months (range, 36-107 months). However, the clinical success rates were 85.7% (18/21 ureters) by 12 months, 61.9% (14/21 ureters) by 24 months, and 52.4% (11/21 ureters) after 36 months. During follow-up, obstructions could not be resolved using metallic stents in eleven ureters (median time to failure, 18.4 months; range, 2-40 months); therefore, they were treated with nephrectomy (three ureters because of a nonfunctional kidney) or percutaneous nephrostomy and double J stent placement (four ureters). Major complications included the encrustation of the metallic stent, flank pain, and gross hematuria. A uretero-enteric fistula occurred in one ureter. In two patients, existing metallic stents were removed and patency was maintained. In another two patients, new metallic stents were inserted without complications. Conclusions: Benign and malignant ureteral obstructions may be treated effectively and safely with metallic stents. However, the patency rate drastically decreased and major complications occurred during long-term follow-up. Therefore, careful patient selection is necessary to achieve better results.

Endoleak and Pseudoaneurysm Formation in the Setting of Stent Graft Infection Following Endovascular Uretero-Arterial Fistula Repair: The Dreaded Complication

The complication of uretero-arterial fistula after prolong ureteral stenting is well recognized. The treatment is primarily endovascular stenting across the fistulous communication accepting the potential risk of stent graft infection. Herein we present a case of a 71-year-old female who developed an uretero-arterial fistula after prolong ureteral stenting and exchanges following ileal conduit obstruction. Initial treatment with left common iliac stenting controlled the hematuria, but only temporarily. Repeat angiography revealed a type 1b endoleak requiring stent extension. Unfortunately, persistent hematuria necessitating further angiography showed the development of a saccular pseudoaneurysm around the stent graft requiring proximal stent extension. A nuclear medicine indium 111-tagged white blood cell scan with single-photon emission CT (SPECT)/CT confirmed stent graft infection. Conservative therapy with antibiotics failed, causing graft failure that ultimately required bypass surgery.

Long-term outcomes of two types of metal stent for chronic benign ureteral strictures

BACKGROUND

We aimed to compare the results of long-term use of two types of metal stent for chronic benign ureteral strictures.

METHODS

Our study included 46 ureter units (UUs) that underwent metal stent placement from 2010 to 2017. We included benign ureteral strictures causes by variety reasons that could not be solved by other treatment and malignant obstructions were excluded. Covered mesh stent (Uventa™) and a thermo-expandable stent (Memokath 051™) were used. Primary success was defined as maintaining patency without procedures and overall success was defined as maintaining patency with additional procedures.

RESULTS

We placed covered mesh stents in 25 UUs and thermo-expandable stents in 21 UUs. The mean follow-up duration of each stent was 41.4 ± 23.1 and 34.4 ± 16.5 months (p = 0.250). In the first year of stent insertion, primary success was achieved in 54.9 and 70.4% (p = 0.204). Overall success was achieved in 78.7 and 75.4% in same duration, respectively (p = 0.586). Longer stent placement had positive predictive value on both success rates (HR = 0.185, p = 0.047 and HR = 0.111, p = 0.018). Prior radiation therapy and non-pelvic ureter stricture both adversely affected the overall success rate (HR = 5.412, p = 0.048 and HR = 4.203, p = 0.030). Previous PCN status had negative predictive value for both success rates (HR = 4.014, p = 0.003 and HR = 3.064, p = 0.035).

CONCLUSIONS

The treatment outcomes of two types of metal stent were comparable, especially in the first year of stent insertion.

Ureteroiliac Artery Fistula Caused by a Metallic Memokath Ureteral Stent in a Radiation-Induced Ureteral Stricture

Background: Memokath 051™ stents are increasingly used for management of benign and malignant ureteral strictures refractory to management with single or tandem polymeric Double-J ureteral stents. Migration, encrustation, and difficulty in extraction during stent exchange are the chief problems reported so far with these thermoexpandable metallic stents. We report an unusual complication of ureteroexternal iliac artery fistula (UEAF) caused by Memokath stent inserted for radiation-induced ureteral stricture.

Case Presentation: A 71-year-old male with history of colorectal cancer (underwent extirpative surgery + chemoradiotherapy) and subsequently radiation-induced ureteral stricture had bilateral Memokath ureteral stents inserted. Three months later, he presented with sepsis and hemodynamic instability secondary to UEAF, confirmed on angiography. A covered vascular stent was inserted as an immediate management.

Conclusion: Memokath stent insertion in radiation-induced ureteral strictures may be associated with an increased risk of erosion and the rare potential complication of UEAF. This potential risk needs to be considered in the overall setting of such strictures and the difficulty in treating them. Prompt imaging (angiography) and placement of an endovascular stent are the ideal immediate options in such cases.