title: The effect of three hemostatic agents on early bone healing in an animal model.
abstract: BACKGROUND
  Resorbable bone hemostasis materials, oxidized regenerated cellulose (ORC) and microfibrillar collagen (MFC), remain at the site of application for up to 8 weeks and may impair osteogenesis. Our experimental study compared the effect of a water-soluble alkylene oxide copolymer (AOC) to ORC and MFC versus no hemostatic material on early bone healing.
  
  
  METHODS
  Two circular 2.7 mm non-critical defects were made in each tibia of 12 rabbits. Sufficient AOC, ORC or MFC was applied to achieve hemostasis, and effectiveness recorded. An autologous blood clot was applied to control defects. Rabbits were sacrificed at 17 days, tibiae excised and fixed. Bone healing was quantitatively measured by micro-computed tomography (micro-CT) expressed as fractional bone volume, and qualitatively assessed by histological examination of decalcified sections.
  
  
  RESULTS
  Hemostasis was immediate after application of MFC and AOC, after 1-2 minutes with ORC, and >5 minutes for control. At 17 days post-surgery, micro-CT analysis showed near-complete healing in control and AOC groups, partial healing in the ORC group and minimal healing in the MFC group. Fractional bone volume was 8 fold greater in the control and AOC groups than in the MFC group (0.42 ± 0.06, 0.40 ± 0.03 vs 0.05 ± 0.01, P < 0.001) and over 1.5-fold greater than in the ORC group (0.25 ± 0.03, P < 0.05). By histology, MFC remained at the application site with minimal healing at the defect margins and early fibrotic tissue within the defect. ORC-treated defects showed partial healing but with early fibrotic tissue in the marrow space. Conversely, control and AOC-treated defects demonstrated newly formed woven bone rich in cellular activity with no evidence of AOC remaining at the application site.
  
  
  CONCLUSIONS
  Early healing appeared to be impaired by the presence of MFC and impeded by the presence of ORC. In contrast, AOC did not inhibit bone healing and suggest that AOC may be a better bone hemostatic material for procedures where bony fusion is critical and immediate hemostasis required.
authors.affiliation: Department of Diagnostic and Surgical Sciences, UCLA School of Dentistry, Los Angeles, CA 90095 USA. jonathank.armstrong@gmail.com
authors.forename: Jonathan K
authors.initials: JK
authors.lastname: Armstrong
authors.forename: Bo
authors.initials: B
authors.lastname: Han
authors.forename: Kenrick
authors.initials: K
authors.lastname: Kuwahara
authors.forename: Zhi
authors.initials: Z
authors.lastname: Yang
authors.forename: Clara E
authors.initials: CE
authors.lastname: Magyar
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Dry
authors.forename: Elisa
authors.initials: E
authors.lastname: Atti
authors.forename: Sotirios
authors.initials: S
authors.lastname: Tetradis
authors.forename: Timothy C
authors.initials: TC
authors.lastname: Fisher
mesh_terms: D000818:Animals; D001842:Bone and Bones / Q000187:drug effects*; D004195:Disease Models, Animal; D006487:Hemostasis; D006490:Hemostatics / Q000494:pharmacology*; D010012:Osteogenesis / Q000187:drug effects*; D011817:Rabbits; D014945:Wound Healing / Q000187:drug effects*
chemical_list: D006490:Hemostatics