title: [Pyeloureteral stenting using nitinol stents].
abstract: OBJECTIVE
  To test the effectiveness of nitinol stents in restoring patency of pyeloureteral segment (PUS).
  
  
  METHODS
  Endoureteral nitinol stents were used in 54 patients. The indications for stenting were recurrent strictures of upper urinary tract and ureteral tumor obstruction in 34 and 20 patients, respectively. In 9 (16.6%) of them, including 4 women and 5 men aged 28-65 years, stenting was performed for extensive recurrent PUS strictures. In 8 patients extensive strictures resulted from various surgical interventions on the PUS. In 2 patients, PUS narrowing was caused by open pyelolithotomy, in 6 patients by pyeloplasty, both open (4) and laparoscopic (2). A female patient with solitary right kidney and Bourneville - Pringle disease of the PUS received two metal prostheses.
  
  
  RESULTS
  In all cases, nitinol stents were adequately installed in PUS. Hematuria was observed in 1 patient. During the follow-up period of 8 to 60 months, the results of stenting were considered good in 6 (66.7%) and satisfactory in 2 (22.2%) patients. At month 10, 1 (11.1%) patient developed the stent obstruction by proliferative tissue and underwent ureteroscopy with recanalization of the nitinol stent. The patient with Bourneville - Pringle disease was found to have a stone formed in the renal pelvic end of the endoprosthesis; she underwent percutaneous nephrolithotripsy. In another patient a lower calyceal stone migrated and wedged into the proximal end of the stent. The stone was extracted using percutaneous nephroscopy.
  
  
  CONCLUSIONS
  Pyeloureteral stenting is an effective method to restore patency of the PUS in patients with extensive recurrent strictures. For adequate functioning of the stents, they need to be of optimal length and correctly installed.
authors.affiliation: Department of Urology, I.I. Mechnikov North-Western State Medical University, St. Petersburg.
authors.forename: B G
authors.initials: BG
authors.lastname: Guliev
authors.affiliation: Department of Urology, I.I. Mechnikov North-Western State Medical University, St. Petersburg.
authors.forename: A M
authors.initials: AM
authors.lastname: Zagazezhev
mesh_terms: D000328:Adult; D000368:Aged; D000497:Alloys; D005260:Female; D006801:Humans; D007682:Kidney Pelvis / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000628:therapy; D015607:Stents; D016896:Treatment Outcome; D014517:Ureteral Obstruction / Q000601:surgery*; D013520:Urologic Surgical Procedures / Q000009:adverse effects / Q000295:instrumentation
chemical_list: D000497:Alloys; C013616:nitinol
keywords: endoprosthesis; nitinol stent; pyeloureteral segment; stricture; ureter