Stent-associated urolithiasis in children: A case reports

In the treatment of children with urolithiasis, ureteral stents are used to relieve ureteral obstruction, often caused by stones migrating from the upper urinary tract. Stenting is an effective surgical procedure to use when conservative treatment has failed. However, a ureteral stent can cause side effects or complications, including salt encrustation. Few reports of such adverse effects of ureteral stents in pediatric urology prompted us to describe cases of stent-related complications, including
migration, fragmentation, and incrustation.

The aim of this paper is to present our experience in the treatment of stent-associated urolithiasis in children.

Case description No. 1. A 16-year-old female patient was treated for complaints of persistent abdominal pain (above the pubic bone), increased urinary frequency, and dysuria. She has a history of ureteral stent removal (heavily encrusted with salts) 2 months ago; the stent was placed for renal colic associated with urolithiasis. A bladder stone was found during the examination. Urethrocystoscopy and contact laser lithotripsy were performed. The calculus was completely fragmented. The girl was discharged on day 5 after the surgery.

Case description No. 2. A 16-year-old female patient was admitted to the Urology Department for routine staged treatment of urolithiasis including lithotripsy of stones in the right 
kidney, the upper third of the right ureter with a stent in the right kidney. She had a history of contact laser ureterolithotripsy 
4 months ago (a calculus of the middle third of the right ureter was fragmented, a dendritic calculus of the right kidney was partially fragmented, and a ureteral stent was replaced. Flexible ureterorenoscopy and right-sided contact laser lithotripsy were required. Extensive incrustation of the distal stent was observed intraoperatively. Removal attempt failed (fixed in the proximal segment). Ureteral exploration in the pyelourethral segment revealed calculus in the proximal segment of the stent. During 
contact lithotripsy of a calculus on a stent, a ureteral catheter fractured. A flexible ureterorenoscope and laser lithotripter were used for stone fragmentation in the right kidney. The proximal segment of the stent could not be removed due to the high risk of ureteral injury. After a medical pause (after 4 weeks), a repeat flexible ureterorenoscopy, right-sided contact laser lithotripsy and right-sided foreign body removal (stent site) were performed. The girl was discharged in satisfactory condition on day 3 after surgery. A review of the medical literature revealed a lack of guidelines for successfully managing these potentially serious conditions. Two clinical cases with similar complications and ways to solve them were found and described in foreign sources.