EAU 2018: Complicated Removal of an Encrusted Allium™ Ureteral Stent

Copenhagen, Denmark (UroToday.com) Ureteral stents are one of the most commonly used items in Urologists armamentarium. Ureteral stents provide adequate drainage but when placed for long term, there is an increased risk of incrustation and stone formation. There are stents that ostensibly have anti-incrustation coated surface which allow them to be utilized for long term use. Once the incrustations take place, the removal and any endoscopic manipulations become very challenging. 

Dr. E.X. Keller, clinical urologist from the Pierre et Marie Curie University in Paris, France, presented a case report of a 66 year old male with ureteral stenosis and recurring stone disease. An Allium™ stent was placed in the  right distal ureter of the patient 9 months prior to the date of the case report. According to the manufacturer, Allium Medical, this particular stent is ideal for long-term ureteral stenting as it features a polymeric coating to prevent tissue in-growth into the lumen, encrustation, and calcification of the stent. When the patient returned to the center for stent removal, a diagnostic ureteroscopy was performed to determine the condition of the stent before removal. Contrary to the claims of the manufacturer, the diagnostic revealed calcifications along the entire lumen of the ureteral stent. 

For the first trial of stent extraction via ureteroscopy, a 3.0 Fr Boston Scientific® Tricep™ with a distal nitinol loop was utilized to attempt to remove the stent. Though this device is usually stable enough for automatic foreign body extraction, it was unable to extract the calcified stent after several attempts. The second trial involved 3.0 Fr Boston Scientific® Piranha™ forceps to attempt to remove the stent, but this too was unable to extract the stent. Finally, a foreign-body grasper was utilized to make the extraction of the calcified stent possible. High force levels were necessary in order to extract the distal end of the stent. In order for the stent to be removed, the coating had to be dismantled which ruptured the stent. The foreign body forceps were then used to regrasp the remaining disrupted parts of the stent. 

Following the removal of the stent, a control ureteropyelography and control ureteroscopy was performed to assess ureter integrity. This revealed several grade 1 lesions according to the Traxer grading scale. A few remaining calcifications were discovered and removed during the procedure. Two Bard® 7F / 30 mm  tumor stents were inserted in a parallel fashion into the patient to properly drain the kidneys to prevent future calcifications. 

In conclusion, Dr. Keller reminded the audience that the removal of Allium™ ureteral stents are not always as easy as the manufacturer claims. Potential complications include possible defective unraveling, calcifications, ureteral mucosa edema, and ureteral mucosa lesions. 

Presented by: E.X. Keller, Pierre et Marie Curie University, Dept. of Urology, Paris, France

Co-Authors: Keller Keller E.X. , De Coninck V. , Rodriguez-Monsalve M. , Doizi S. , Traxer O.
Author Information: Tenon Hospital, Assistance-Publique H.pitaux de Paris. Pierre et Marie Curie University, Dept. of Urology, Paris, France

Written by: Zachary Valley and Zhamshid Okhunov, MD, (Department of Urology, University of California-Irvine) at the 2018 European Association of Urology Meeting EAU18, 16-20 March, 2018 Copenhagen, Denmark