title: Pilot study: fibrin sealant in anal fistula model.
abstract: OBJECTIVE
  The aim of this study was to investigate the failure of fibrin sealant treatment for fistula-in-ano in an experimental porcine model and to determine histologic changes associated with the sealant and setons.
  
  
  METHODS
  Three surgically created fistulas were treated by seton drainage in each of eight male pigs. After 26 days, magnetic resonance imaging was performed and setons were removed. Two pigs were killed as controls for stereologic histologic fistula track assessment. In six, fistulas were curetted, and in four the fistulas were treated with fibrin sealant. In these four sealant and two seton pigs, magnetic resonance imaging was repeated a median of 47.5 days after fistula formation. The pigs were killed and stereologic histologic fistula track examination was performed to determine granulation tissue and fistula lumen volumes. These values were compared among control, seton, and sealant groups over time, and related to fistula volumes derived from magnetic resonance imaging.
  
  
  RESULTS
  Sealant was not visible microscopically within tracks, although some sections revealed a foreign body-type reaction. On stereologic assessment, granulation tissue volumes were smaller in sealant and seton groups than in controls (median, 88 vs. 187 vs. 453 mm3, respectively; P = 0.002) and decreased over time (median, 408 and 152 mm3 (Day 42) vs. 88 and 75 (Day 53), respectively; P = 0.002). Fistula lumen (P < 0.001), and granulation tissue combined with fistula lumen volumes (P = 0.002) were similarly smaller. Magnetic resonance imaging of fistula intensity was less in the sealant group than in the seton group and controls (mean, 777 vs. 978 vs. 1214 units/mm2, P = 0.003). Magnetic resonance imaging fistula volumes were least in sealant and seton groups vs. controls (P = 0.024), decreasing significantly in the sealant group over time (P = 0.018). No direct relationship was found between imaging and histologic volumes.
  
  
  CONCLUSIONS
  In an experimental porcine model of anal fistula, granulation tissue was still present, albeit diminished, following track curettage combined with seton or sealant therapy, and was minimal in the sealant group, confirming some benefit from this procedure. Eradication of all longstanding granulation tissue may ensure complete success of fibrin sealant therapy.
authors.affiliation: Department of Surgery, St. Mark's Hospital, Harrow, United Kingdom.
authors.forename: Gordon N
authors.initials: GN
authors.lastname: Buchanan
authors.forename: Paul
authors.initials: P
authors.lastname: Sibbons
authors.forename: Mike
authors.initials: M
authors.lastname: Osborn
authors.forename: Clive I
authors.initials: CI
authors.lastname: Bartram
authors.forename: Tahera
authors.initials: T
authors.lastname: Ansari
authors.forename: Steve
authors.initials: S
authors.lastname: Halligan
authors.forename: C Richard G
authors.initials: CR
authors.lastname: Cohen
mesh_terms: D000818:Animals; D002404:Catheterization; D004195:Disease Models, Animal; D015718:Fibrin Tissue Adhesive / Q000627:therapeutic use*; D006099:Granuloma / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D012003:Rectal Fistula / Q000628:therapy* / Q000662:veterinary; D013552:Swine; D014014:Tissue Adhesives / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D015718:Fibrin Tissue Adhesive; D014014:Tissue Adhesives