title: Healos/recombinant human growth and differentiation factor-5 induces posterolateral lumbar fusion in a New Zealand white rabbit model.
abstract: METHODS
  Posterolateral lumbar spine fusions in New Zealand white rabbits.
  
  
  OBJECTIVE
  To evaluate the efficacy of recombinant human growth and differentiation factor-5 (rhGDF-5) lyophilized to a Healos carrier (cross-linked type I collagen with hydroxyapatite coating; DePuy Spine, Inc., Raynham, MA) in inducing fusion.
  
  
  BACKGROUND
  Bone graft substitutes have become an area of considerable interest. rhGDF-5 is one such product. Limited lumbar preclinical studies have been performed with this product.
  
  
  METHODS
  Single-level, intertransverse process fusions were performed in 67 rabbits using iliac crest autograft (n = 13), Healos alone (n = 13), or 0.5, 1.0, or 1.5 mg/cc rhGDF-5 lyophilized to Healos (n = 13 per group). At 8 weeks, the rabbits were euthanized. Fusion masses were assessed.
  
  
  RESULTS
  There were 2 animals (3%) lost to complication. Manual palpation revealed fusion rates for autograft of 38% (5/13), Healos alone of 0% (0/13), and each of the Healos/rhGDF-5 groups of 100% (13/13). Histologic analyses were 95% sensitive and 95% specific for confirming fusion. Histologic differences were found among the treatment groups.
  
  
  CONCLUSIONS
  In this rabbit fusion model, Healos/rhGDF-5 induced fusion in 100% of the rabbits studied. This rate was significantly higher than the fusion rate induced by autograft (38%). Overall, these results support continued research of Healos/rhGDF-5 as a potential bone graft alternative.
authors.affiliation: Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
authors.forename: David P
authors.initials: DP
authors.lastname: Magit
authors.forename: Travis
authors.initials: T
authors.lastname: Maak
authors.forename: Nancy
authors.initials: N
authors.lastname: Trioano
authors.forename: Bradley
authors.initials: B
authors.lastname: Raphael
authors.forename: Quasai
authors.initials: Q
authors.lastname: Hamouria
authors.forename: Gert
authors.initials: G
authors.lastname: Polzhofer
authors.forename: Inneke
authors.initials: I
authors.lastname: Drespe
authors.forename: Todd J
authors.initials: TJ
authors.lastname: Albert
authors.forename: Jonathan N
authors.initials: JN
authors.lastname: Grauer
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D018786:Bone Substitutes / Q000494:pharmacology*; D016025:Bone Transplantation / Q000379:methods*; D024042:Collagen Type I / Q000494:pharmacology; D017886:Durapatite / Q000494:pharmacology; D005260:Female; D055428:Growth Differentiation Factor 5; D023421:Models, Animal; D011817:Rabbits; D011994:Recombinant Proteins / Q000494:pharmacology; D013123:Spinal Fusion / Q000379:methods*; D013131:Spine / Q000187:drug effects*; D014182:Transplantation, Autologous
chemical_list: D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D024042:Collagen Type I; C525893:GDF5 protein, human; D055428:Growth Differentiation Factor 5; D011994:Recombinant Proteins; D017886:Durapatite