title: Anorectal transplantation.
abstract: BACKGROUND
  Anorectal transplantation is a valid procedure for the treatment of anorectal dysfunction; however, the lack of a suitable animal model has hampered the development of this method. We describe a simple technique for anorectal transplantation in the rat and compare this procedure with colostomy.
  
  
  METHODS
  The anorectal segment including the skin surrounding the anus were freed by abdominal and perineal dissection. In a heterotopically transplanted group the segment was exteriorized by the formation of an anus through an abdominal incision. In an orthotopically transplanted group the segment was replaced in its original position and reimplanted by suturing. In another group a distal colostomy was performed. A sham-treated control group (simulated surgical procedure) was also included. Changes in behavior, characteristics of the stool, body weight and survival rate were assessed by daily clinical examination. Moribund animals, those with a weight loss of more than 30%, and those surviving at 1 month were killed by an overdose of anesthetic. The results were analyzed using the Mann Whitney, Student's t and chi-squared tests, and p<0.05 was considered significant.
  
  
  RESULTS
  Within 4 days after the operation, animals submitted to orthotopic or heterotopic transplantation had achieved normal defecation, body weight gain and clinical evolution similar to the sham-treated group. The overall mortality in these groups was 4.16%. In contrast, colostomized animals showed a high incidence of diarrhea, intestinal obstruction, stress posture and violent behavior (p</=0.05), and a mortality rate of 58.33%.
  
  
  CONCLUSIONS
  Autotransplantation in the rat is a simple technique, achieves a high rate of success and better clinical evolution than colostomy. This model may ultimately lead to research into anorectal transplantation.
authors.affiliation: Department of Gastroenterology, Division of Transplantation, Hospital das Clinicas, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil. fgalvao@usp.br
authors.forename: F H Ferreira
authors.initials: FH
authors.lastname: Galvão
authors.forename: V E
authors.initials: VE
authors.lastname: Seid
authors.forename: R M
authors.initials: RM
authors.lastname: Nunes dos Santos
authors.forename: M
authors.initials: M
authors.lastname: Kitamura
authors.forename: R
authors.initials: R
authors.lastname: de Castro Galvão
authors.forename: R
authors.initials: R
authors.lastname: Ambar Pinto
authors.forename: R
authors.initials: R
authors.lastname: Miyashiro Nunes dos Santos
mesh_terms: D001003:Anal Canal / Q000637:transplantation*; D000818:Animals; D003125:Colostomy / Q000379:methods*; D003672:Defecation; D004195:Disease Models, Animal; D005242:Fecal Incontinence / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012007:Rectum / Q000637:transplantation*; D016896:Treatment Outcome