title: Hemorrhoids: an experimental model in monkeys.
abstract: OBJECTIVE
  Hemorrhoids are a matter of concern due to a painful outcome. We describe a simple, easy and reliable experimental model to produce hemorrhoids in monkeys.
  
  
  METHODS
  14 monkeys (Cebus apella) were used. After general anesthesia, hemorrhoids were induced by ligation of the inferior hemorrhoidal vein, which is very alike to humans. The vein was located through a perianal incision, dissected and ligated with a 3-0 vicryl. The skin was sutured with a 4-0 catgut thread. Animals were kept in appropriate cages and evaluated daily.
  
  
  RESULTS
  Nine days later there were hemorrhoidal piles in the anus in fifty percent (50%) of the animals. Outcome was unremarkable. There was no bleeding and all animals showed no signs of pain or suffering.
  
  
  CONCLUSIONS
  This is an affordable and reliable experimental model to induce hemorrhoids for experimental studies.
authors.affiliation: Department of Surgery, Federal University of São Paulo (UNIFESP), São Paulo, Brazil. helio@plapler.com.br
authors.forename: Hélio
authors.initials: H
authors.lastname: Plapler
mesh_terms: D000818:Animals; D002428:Cebus; D004195:Disease Models, Animal; D006484:Hemorrhoids / Q000209:etiology*; D008026:Ligation; D008297:Male; D010149:Postoperative Pain