Presented by: Joerg Neymeyer Dr.
Medical University Charite - Berlin - Department of Urology

Introduction

Allium Ureteral Stents (AUS) are self-expandable, metallic stents (Nitinol) which is fully coated with Co-Polymer. It is used for ureteral strictures, ureterovaginal fistula, and ureteral avulsion treatments. Encrustation of the stent is one of feared complications of urinary tract stents. For AUS despite the protective effect of Co-Polymer against encrustation, this condition is always argued.

Materials

Charts of the patients who inserted AUS since 2011 were evaluated. Data regarding AUS encrustation including indication of stents, duration till the encrustation, degree of encrustation and management type were noted.

Results

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1109 AUS cases. The indications were: ureteral stricture in 823 patients, ureterovaginal fistula in 214 patiens and partial/total ureteral avulsion in 72 patients. Of them 27 patients diagnosed with stent encrustation wit CT scan, 19 were partially obstructing the stent lumen and 8 were totally obstructing urine passage through the stent. The duration till the encrustation were 30-36 months. Cases with partial obstruction were treated with just ureteroscopic stent removal. A strong grasper was enough for this aim, no intraluminal stone fragmentation was needed. Cases with total obstruction due to encrustation a pneumatic lithotripter was used for stone fragmentation inside of the AUS, and then stent removal was performed. One case has a stone formation in the renal pelvis, thus a percutenous access was needed for stone and stent removal. We did not observe a tissue ingrowth and ureteral damage during stent removal.

Conclusion

Despite the co—polymer coating an encrustation may occur. The rate is acceptable and endoscopic management with pneumatic lithotripter and a strong grasper is an effective option. To reduce the chance of encrustation, decreasing AUS indwelling time (2 years) may be helpful. Periodic evaluation of the patient with US and CT scan is necessary to diagnose hydronephrosis and encrustation for early diagnosis.

Funding

none

Lead Authors

Alkan Cubuk, Dr.
Kocaeli University Hospital - Department of Urology

Sarah Weinberger, Dr.
Medical University Charite - Berlin - Department of Urology

Katahrina-Sophie Mala, Dr.
Medical University Charite - Berlin - Department of Urology

Antonia Franz, Dr.
Medical University Charite - Berlin - Department of Urology

Viktoria Schaeff, Dr.
Medical University Charite - Berlin - Department of Urology

Thorsten Schlomm, Prof.
Medical University Charite - Berlin - Department of Urology