title: Lack of evidence for tissue hypoxia as a contributing factor in anastomotic leak following colon anastomosis and segmental devascularization in rats.
abstract: OBJECTIVE
  Current surgical dogma dictates that tissue ischemia and hypoxia are major contributing factors in anastomotic leak despite scant evidence. The aim of this study was to determine if tissue hypoxia is a feature of anastomotic leakage in rats following colon resection and segmental devascularization.
  
  
  METHODS
  Rats were randomly assigned to undergo sham operation, segmental colon devascularization alone, colectomy alone, or segmental devascularization plus colectomy. Tissue hypoxia present at the colon anastomosis site across the various treatment groups was determined at sacrifice on postoperative day 6. Pimonidazole HCl was injected 30 min prior to sacrifice. Anastomotic tissues were examined and scored for healing versus leakage using an anastomotic healing score (AHS). Collagen content, hypoxia, enteric smooth muscle and periendothelial stromal patterning, and apoptosis were evaluated histologically.
  
  
  RESULTS
  No differences in tissue hypoxia were noted in the 16% of anastomotic tissues with poor healing compared to the remaining 84% of rats whose anastomoses healed well. No significant changes were found in cell death in the submucosa of any group. Consistent with previous findings, poor healing was associated with lower collagen content. Submucosal thickness correlated with increased arteriole diameter (R2= 0.25, p < 0.005).
  
  
  CONCLUSIONS
  These results demonstrate that tissue hypoxia is not a distinctive feature of anastomotic tissues that fail to heal and leak, even when their blood supply is interrupted. These findings suggest that compensatory factors may mitigate the effects of ischemia and hypoxia during healing of anastomotic tissues and that the process of leakage involves factors beyond their acute effects.
authors.affiliation: Department of Surgery, Center for Surgical Infection Research, Pritzker School of Medicine, 5841 S Maryland Ave, MC 6040, Chicago, IL, 60605, USA.
authors.forename: B A
authors.initials: BA
authors.lastname: Shakhsheer
authors.affiliation: Department of Surgery, Section of Pediatric Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: B
authors.initials: B
authors.lastname: Lec
authors.affiliation: Department of Surgery, Center for Surgical Infection Research, Pritzker School of Medicine, 5841 S Maryland Ave, MC 6040, Chicago, IL, 60605, USA.
authors.forename: A
authors.initials: A
authors.lastname: Zaborin
authors.affiliation: Department of Surgery, Center for Surgical Infection Research, Pritzker School of Medicine, 5841 S Maryland Ave, MC 6040, Chicago, IL, 60605, USA.
authors.forename: K
authors.initials: K
authors.lastname: Guyton
authors.affiliation: Department of Surgery, Section of Pediatric Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: A M
authors.initials: AM
authors.lastname: Defnet
authors.affiliation: Department of Surgery, Section of Pediatric Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: N
authors.initials: N
authors.lastname: Bagrodia
authors.affiliation: Department of Surgery, Section of Pediatric Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Kandel
authors.affiliation: Department of Surgery, Center for Surgical Infection Research, Pritzker School of Medicine, 5841 S Maryland Ave, MC 6040, Chicago, IL, 60605, USA.
authors.forename: O
authors.initials: O
authors.lastname: Zaborina
authors.affiliation: Department of Surgery, Section of Pediatric Surgery, The University of Chicago, Chicago, IL, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Hernandez
authors.affiliation: Department of Surgery, Center for Surgical Infection Research, Pritzker School of Medicine, 5841 S Maryland Ave, MC 6040, Chicago, IL, 60605, USA. jalverdy@surgery.bsd.uchicago.edu.
authors.forename: J
authors.initials: J
authors.lastname: Alverdy
mesh_terms: D000714:Anastomosis, Surgical / Q000009:adverse effects; D057868:Anastomotic Leak / Q000209:etiology*; D000818:Animals; D017209:Apoptosis; D003094:Collagen / Q000378:metabolism; D003106:Colon / Q000098:blood supply* / Q000601:surgery*; D000860:Hypoxia / Q000473:pathology*; D007413:Intestinal Mucosa / Q000473:pathology / Q000601:surgery; D008297:Male; D017208:Rats, Wistar; D014945:Wound Healing
chemical_list: D003094:Collagen
keywords: Anastomosis; Anastomotic leak; Colon anastomosis; Hypoxia; Tissue hypoxia