title: Hydrated vs. freeze-dried human acellular dermal matrix for hernia repair: a comparison in a rabbit model.
abstract: BACKGROUND
  Abdominal wall hernias commonly occur following laparotomy. Biologic grafts are used to treat these hernias due to their biocompatibility and their ability to serve as a matrix for tissue regeneration and remodeling. Freeze-dried human acellular dermal matrices (F-HADMs) have been shown to be effective in abdominal wall defect repair. Hydrated human acellular dermal matrices (H-HADMs) have not been previously evaluated. This study evaluates H-HADM and F-HADM in the repair of abdominal wall hernias in the rabbit.
  
  
  METHODS
  Thirty-six 3-4-kg New Zealand white rabbits underwent laparotomy with the creation of a hernia. After defect reperitonealization, the animals underwent hernia repair with H-HADM, F-HADM, or primary repair. Within each group, four animals were survived for 4, 8, and 20 weeks. The outcomes evaluated included recurrences, adhesions, histology, immunohistochemistry, and tensiometry.
  
  
  RESULTS
  Thirty-five animals underwent abdominal wall hernia repair. One animal in the F-HADM group developed a recurrent hernia. No significant difference was demonstrated in adhesion scores between the H-HADM (0.75) and F-HADM (0.83) groups. Tensiometry demonstrated no differences in the forces required to disrupt the graft from the native fascia between H-HADM and F-HADM at any time point. H-HADM demonstrated fewer white blood cells (WBC) and eosinophils (EOS) per high-powered field (hpf) than F-HADM at 4 weeks (144 WBC/hpf vs. 534 WBC/hpf, P < 0.05; 87 EOS/hpf vs. 304 EOS/hpf, P < 0.05) and 8 weeks (104 WBC/hpf vs. 314 WBC/hpf, P < 0.05; 41 EOS/hpf vs. 149 EOS/hpf, P < 0.05). At 20 weeks, there was no difference in WBC or EOS (134 WBC/hpf vs. 144 WBC/hpf, P = NS; 86 EOS/hpf vs. 104 EOS/hpf, P = NS). Immunohistochemistry for CD31 demonstrated no difference in vascularity at any time point.
  
  
  CONCLUSIONS
  H-HADM and F-HADM demonstrate comparable results in abdominal wall hernia treatment in a rabbit model. With both grafts, the weakest area of the repair occurs at the graft and native fascia interface. Hernia repairs with H-HADM and F-HADM demonstrate similar incidences of adhesions and tensile strength characteristics. H-HADM demonstrates a reduced inflammatory response at 4 and 8 weeks compared to F-HADM. Both H-HADM and F-HADM demonstrate similar amounts of vascular ingrowth.
authors.affiliation: Department of Surgery, University of Kentucky College of Medicine, 800 Rose Street, Lexington, KY 40536, USA. s.roth@uky.edu
authors.forename: J S
authors.initials: JS
authors.lastname: Roth
authors.forename: D D
authors.initials: DD
authors.lastname: Dexter
authors.forename: K
authors.initials: K
authors.lastname: Lumpkins
authors.forename: G V
authors.initials: GV
authors.lastname: Bochicchio
mesh_terms: D000818:Animals; D003094:Collagen; D003681:Dehydration; D005612:Freeze Drying; D046449:Hernia, Abdominal / Q000601:surgery*; D006801:Humans; D010147:Pain Measurement; D011183:Postoperative Complications / Q000517:prevention & control; D011817:Rabbits; D011897:Random Allocation; D012008:Recurrence; D013526:Surgical Mesh; D013529:Surgical Wound Dehiscence / Q000517:prevention & control; D013536:Suture Techniques; D014945:Wound Healing / Q000502:physiology*
chemical_list: C440568:Alloderm; D003094:Collagen