title: The Role of Tandem Double-J Ureteral Stents in the Management of Malignant Ureteral Obstruction.
abstract: OBJECTIVE
  The management of malignant ureteral obstruction (MUO) is a challenging but common problem for urologists. The different techniques currently used to address this complicated issue include percutaneous nephrostomy, extra-anatomical stents, retrograde (single) stent insertion, and metallic stents. In those situations where single ureteral stent insertion has failed, retrograde tandem or twin ureteral stent (TUS) insertion can be completed. The aim of this study was to report our clinical experience and also assess the efficacy of TUS insertion within our tertiary referral center.
  
  
  METHODS
  Data were prospectively collected from patients requiring TUSs over an 8-year period between January 1, 2006, and December 31, 2014. A number of variables, including the improvement in renal function following TUS insertion, were recorded.
  
  
  RESULTS
  Twenty-two TUS insertion procedures were performed on 15 patients between the period of January 1, 2006, and December 31, 2014. The mean patient age was 68.0 years (39-85 years). There were 15 primary insertions as well as 7 subsequent stent changes. The average prenephrostomy creatinine was 428 μmol/L; an average improvement of 196 μmol/L was observed after percutaneous drainage. Serum creatinine after TUS remained stable on discharge, 214 μmol/L vs 227 μmol/L preoperatively, p = 0.34. Eleven patients died at a median 131 days post-TUS insertion. TUS failure occurred in three patients; this was characterized by rising creatinine and worsening hydronephrosis. Patients with failing TUS had a median life expectancy of 45.6 days compared with 162.5 days for those with functioning TUS (p < 0.05). Overall, the patency rate at 3 months was 80%.
  
  
  CONCLUSIONS
  TUS insertion is a technically efficient and effective procedure in the management of MUO, with the majority of patients treated dying of the underlying condition with functioning stents in situ.
authors.affiliation: 1 Department of Urology, St George's Hospital NHS Foundation Trust , London, United Kingdom .
authors.forename: Michalis
authors.initials: M
authors.lastname: Varnavas
authors.affiliation: 2 Department of Urology, Darent Valley Hospital , Kent, United Kingdom .
authors.forename: Marco
authors.initials: M
authors.lastname: Bolgeri
authors.affiliation: 1 Department of Urology, St George's Hospital NHS Foundation Trust , London, United Kingdom .
authors.forename: Saheel
authors.initials: S
authors.lastname: Mukhtar
authors.affiliation: 1 Department of Urology, St George's Hospital NHS Foundation Trust , London, United Kingdom .
authors.forename: Ken
authors.initials: K
authors.lastname: Anson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous; D011183:Postoperative Complications; D011446:Prospective Studies; D015607:Stents; D016896:Treatment Outcome; D014513:Ureter / Q000601:surgery; D014516:Ureteral Neoplasms / Q000601:surgery*; D014517:Ureteral Obstruction / Q000601:surgery*; D013520:Urologic Surgical Procedures