title: A short biodegradable helical spiral ureteric stent provides better antireflux and drainage properties than a double-J stent.
abstract: OBJECTIVE
  The use of ureteric stents is a standard treatment for the relief of ureter blockages for benign or malignant reasons. The most common stent design in clinical use is a double-J stent with coiled ends to avoid stent displacement. However, there are a number of complications associated with stent use. A double-J stent design bypasses the ureterovesical junction, enables bladder pressure reflection to the renal pelvis and causes vesicoureteral reflux (VUR). This may result in scarring and renal failure.
  
  
  METHODS
  An animal model was used to investigate whether VUR can be avoided in stented ureters using a short biodegradable partial helical spiral stent design that leaves the ureterovesical junction intact.
  
  
  METHODS
  Eight female pigs were used. Ureters on the left side were stented using a short helical spiral SR-PLGA stent (group A) and ureters on the right side using double-J stents (group B). Simulated voiding cystoureterography and standard intravenous urography examinations were performed on all eight animals at 4 weeks and on the remaining four animals at 8 weeks.
  
  
  RESULTS
  An SR-PLGA single coiled partial stent demonstrated superior drainage properties to a double-J stent at 4 weeks (p = 0.020). A marked but not statistically significant difference in favour of a SR-PLGA stent was also observed at 8 weeks (p = 0.102). A statistically significant difference was observed in VCUG findings in favour of group A at immediate postoperative control as well as in the 4 and 8 week follow-up studies (p = 0.011, p = 0.010, p = 0.046, respectively).
  
  
  CONCLUSIONS
  A self-expandable, SR-PLGA partial ureteric stent presented with superior drainage and antireflux properties compared to a double-J stent. The reflux commonly related to double-J stent use can be minimized by using a partial ureteric stent design.
authors.affiliation: Department of Surgery, Kuopio University Hospital, Kuopio, Finland. juha.lumiaho@kuh.fi
authors.forename: Juha
authors.initials: J
authors.lastname: Lumiaho
authors.forename: Antero
authors.initials: A
authors.lastname: Heino
authors.forename: Sirpa
authors.initials: S
authors.lastname: Aaltomaa
authors.forename: Tero
authors.initials: T
authors.lastname: Välimaa
authors.forename: Martti
authors.initials: M
authors.lastname: Talja
mesh_terms: D020341:Absorbable Implants / Q000145:classification*; D000818:Animals; D053715:Cystotomy; D005260:Female; D005548:Foreign-Body Migration; D019344:Lactic Acid; D023421:Models, Animal; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D015607:Stents / Q000145:classification*; D013552:Swine; D014513:Ureter / Q000503:physiopathology / Q000601:surgery*; D014517:Ureteral Obstruction / Q000503:physiopathology / Q000601:surgery; D001743:Urinary Bladder / Q000503:physiopathology*; D014554:Urination / Q000502:physiology*; D014567:Urography; D014718:Vesico-Ureteral Reflux / Q000503:physiopathology / Q000517:prevention & control*
chemical_list: D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid