title: Drainage and antireflux characteristics of a biodegradable self-reinforced, self-expanding X-ray-positive poly-L,D-lactide spiral partial ureteral stent: an experimental study.
abstract: OBJECTIVE
  To evaluate the drainage and antireflux characteristics of a new self-expandable self-reinforced poly-L,D-lactide partial ureteral stent (SR-PLA 96) in an experimental model.
  
  
  METHODS
  Twelve dogs were used as experimental animals. A low-midline laparotomy and cystotomy were performed on all animals. In group A (six animals), 50-mm long SR-PLA 96 ureteral stents with a double-helical spiral design were inserted into both ureters, leaving the lower ends 2 cm above the ureterovesical junction. In group B (six animals), both ureters were stented with traditional pigtail stents (C-Flex) Double-J; Cook Urological), which were removed 8 weeks after surgery. Renal function and ureteral patency were evaluated by dynamic kidney imaging and urography examinations at 6 and 12 weeks postoperatively. The degrees of vesicoureteral reflux at two levels of the ureters and at the level of the renal pelvis were evaluated by nuclear voiding cystograms at 6 weeks.
  
  
  RESULTS
  The partial SR-PLA 96 stent design showed more favorable antireflux properties that the Double-J stent design. The degree of vesicoureteral reflux, reflected in an increase of nuclear enhancement at 6 weeks, was lower in the distal (7.9% +/- 14.7% v 63.2% +/- 17.3%; P < 0.05) and middle (6.1% +/- 8.1% v. 45.5% +/- 19.5%; P = 0.15) levels of the ureters as well as at the level of the renal pelvis (-3.4% +/- 3.6% v 6.2% +/- 3.9%; P = 0.65) than in the Double-J-stented ureters. No significant differences in renal function or ureteral patency were observed at 12 weeks after the Double-J stents had been removed and the SR-PLA 96 stents had fragmented.
  
  
  CONCLUSIONS
  A self-expandable, self-reinforced SR-PLA 96 partial ureteral stent showed more favorable antireflux properties than a Double-J stent.
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: Tomi
authors.initials: T
authors.lastname: Kauppinen
authors.forename: Martti
authors.initials: M
authors.lastname: Talja
authors.forename: Esko
authors.initials: E
authors.lastname: Alhava
authors.forename: Tero
authors.initials: T
authors.lastname: Välimaa
authors.forename: Pertti
authors.initials: P
authors.lastname: Törmälä
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D019344:Lactic Acid; D008567:Membranes, Artificial; D011091:Polyesters; D011108:Polymers; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000295:instrumentation*; D011860:Radiography, Abdominal; D015607:Stents; D016896:Treatment Outcome; D014517:Ureteral Obstruction / Q000000981:diagnostic imaging / Q000601:surgery*; D014567:Urography; D013520:Urologic Surgical Procedures / Q000379:methods*; D014718:Vesico-Ureteral Reflux / Q000517:prevention & control*
chemical_list: D008567:Membranes, Artificial; D011091:Polyesters; D011108:Polymers; D019344:Lactic Acid; C033616:poly(lactide)