title: Role of acellular collagen matrix surgisis in the endoscopic management of ureteropelvic junction obstruction.
abstract: OBJECTIVE
  To investigate the role of acellular collagen matrix (Surgisis during endopyelotomy.
  
  
  METHODS
  Nine female pigs (25-35 kg) were enrolled in our protocol. The pigs were categorized as follows. Group I (N = 3) had endopyelotomy + insertion of SIS, Group II (N = 3) creation of UPJ stricture + endopyelotomy + insertion of SIS, and Group III (N = 3) Davis intubated ureterotomy using SIS. The contralateral side served as a control for each group (one pig in each group). In three pigs (two in Group III and one in Group II), Surgisis was treated with India ink prior to insertion at the endopyelotomy site. An endopyelotomy stent (14/8 F x 24 cm) was used to stent the ureteropelvic junction (UPJ) for 4 weeks. Four weeks after the stent was removed, laparoscopic nephroureterectomy was performed, and the animals were euthanized. Histopathologic analysis of the Surgisis-regenerated segment of the UPJ was performed using hematoxylin and eosin, reticular (collagen), smooth muscle actin, and S-100 (nerve) stains.
  
  
  RESULTS
  All animals tolerated the procedure. The mean operative time was 162 minutes. One pig (Group II) developed pyonephrosis; one pig (Group III) developed significant ascites and was sacrificed 2 week before the end of the experiment. Histopathologic analysis showed complete epithelializaton at 8 weeks. Reticular stain demonstrated abundant collagen matrix in the submucosa. Smooth muscle staining revealed myofibroblastic proliferation within the SIS-regenerated tissue adjacent to disorganized smooth muscle cells. India ink-stained SIS-regenerated tissue did not show smooth muscle cells. The S-100 stain did not demonstrate neurons at 8 weeks; however, in three pigs, peristaltic activity was noted across the UPJ.
  
  
  CONCLUSIONS
  The use of acellular collagen matrix in the endoscopic management of UPJ obstruction is a promising technique. The abundance of myofibroblasts and absence of abundant smooth muscle regeneration indicates a need to investigate the role of growth factors in SIS regeneration of host tissue.
authors.affiliation: Department of Urology, Long Island Jewish Medical Center, New Hyde Park, New York 11040, USA. Pyonnes@hotmail.com
authors.forename: Paulos
authors.initials: P
authors.lastname: Yohannes
authors.forename: Paul
authors.initials: P
authors.lastname: Rotariu
authors.forename: Evangelos
authors.initials: E
authors.lastname: Liatsikos
authors.forename: Aftab
authors.initials: A
authors.lastname: Malik
authors.forename: Mihai
authors.initials: M
authors.lastname: Alexianu
authors.forename: David
authors.initials: D
authors.lastname: Pinkasov
authors.forename: Nora
authors.initials: N
authors.lastname: Morgenstern
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Lee
authors.forename: Arthur D
authors.initials: AD
authors.lastname: Smith
mesh_terms: D000199:Actins / Q000032:analysis; D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use*; D003094:Collagen / Q000502:physiology* / Q000627:therapeutic use*; D004195:Disease Models, Animal; D004724:Endoscopy / Q000379:methods*; D005260:Female; D007682:Kidney Pelvis / Q000098:blood supply / Q000473:pathology / Q000601:surgery*; D009131:Muscle, Smooth, Vascular / Q000098:blood supply / Q000737:chemistry; D018919:Neovascularization, Physiologic / Q000502:physiology; D012038:Regeneration / Q000502:physiology; D013552:Swine; D014513:Ureter / Q000098:blood supply / Q000473:pathology / Q000601:surgery; D014517:Ureteral Obstruction / Q000473:pathology / Q000601:surgery*; D014519:Ureterostomy / Q000379:methods
chemical_list: D000199:Actins; D001672:Biocompatible Materials; D003094:Collagen