title: A novel anchoring system for colonic stents: a pilot in vivo study in a porcine model.
abstract: BACKGROUND
  Colorectal stents have a proven role in colorectal cancer as palliative care or a bridge to surgery. However, their efficacy and anchoring to the tissue varies according to stent design with stent migration rates up to 50 %. We present preliminary in vivo results of a new end-luminal anchoring system for stent fixation to the rectal canal. The aim was to assess the efficacy and safety of the stent using the anchoring system while subjecting the device to daily abdominal pressures related to daily activities in a porcine animal model.
  
  
  METHODS
  Ex vivo anatomical and physical studies were performed to improve the system's structure and safety. Four female pigs were followed for the acute and chronic (16 weeks) period. Two animals were euthanized and underwent en-bloc pelvic visceral excision and histopathological examination. Device fixation time, animal behavior, device patency, anoscopic examination and histopathological features were assessed.
  
  
  RESULTS
  Mean anchoring time was 13.83 weeks (standard error ± 1.38 weeks). One of the animals experienced early device expulsion with no complications. No obstruction was noted in any of the animals. Macroscopic examination revealed mild focal submucosal scarring in one animal and a normal examination in the other. Hematoxylin and eosin staining revealed mucosal ulceration and mixed inflammatory cell infiltrate, with no signs of granulomata, foreign body giant cell reaction or microabscess formation.
  
  
  CONCLUSIONS
  A novel fixation device designed for long-term intrarectal implantation was well tolerated and maintained anal canal patency without migration. Larger studies are needed before its implementation in humans.
authors.affiliation: Department of Surgery and Transplantation, Chaim Sheba Medical Center, 52621, Tel-Hashomer, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Nevler
authors.forename: U
authors.initials: U
authors.lastname: Willantz
authors.forename: O
authors.initials: O
authors.lastname: Doron
authors.forename: J
authors.initials: J
authors.lastname: Sandbank
authors.forename: Y
authors.initials: Y
authors.lastname: Ziv
mesh_terms: D000818:Animals; D015179:Colorectal Neoplasms / Q000150:complications / Q000601:surgery; D004195:Disease Models, Animal; D005260:Female; D005548:Foreign-Body Migration; D007415:Intestinal Obstruction / Q000209:etiology / Q000601:surgery; D011474:Prosthesis Design; D012007:Rectum / Q000601:surgery*; D015607:Stents; D013552:Swine; D013997:Time Factors; D014025:Titanium
chemical_list: D014025:Titanium