title: Spinal fusion with recombinant human growth and differentiation factor-5 combined with a mineralized collagen matrix.
abstract: The availability of recombinant osteoinductive growth factors and new osteoconductive matrices offers an alternative to the use of autogenous bone (autograft) for grafting indications. This study evaluates the bone-forming activity of a mineralized collagen matrix combined with recombinant human growth and differentiation factor-5 in a rabbit posterolateral spinal fusion model. The activity of three distinct matrix-growth factor formulations is assessed by radiographic, histologic, and mechanical strength methods. Results show that the radiographic density, histologic quality, and mechanical strength of fusion at 12 weeks post-treatment rank consistently within the treatment groups. Optimal formulations are shown to perform similar to autograft in both the rate and strength of fusion. Fusion rates as high as 80% are observed within specific matrix/growth factor formulations. The average biomechanical strength of treated motion segments in the most efficacious formulation is 82% higher than that obtained with autograft, although this difference is not statistically significant. The fusion mass formed in response to matrix/growth factor formulations is composed of normal trabecular bone with a thin outer cortical plate and modest hematopoietic bone marrow. These results demonstrate that the combination of a mineralized collagen matrix with recombinant human growth and differentiation factor-5 maximizes the inherent conductive and inductive properties of each component, respectively, to provide an effective alternative to autograft for bone grafting procedures.
authors.affiliation: Department of Research, Orquest, Inc., Mountain View, California 94043, USA. rspiro@fibrogen.com
authors.forename: R C
authors.initials: RC
authors.lastname: Spiro
authors.forename: A Y
authors.initials: AY
authors.lastname: Thompson
authors.forename: J W
authors.initials: JW
authors.lastname: Poser
mesh_terms: D000818:Animals; D019485:Bone Morphogenetic Proteins; D016025:Bone Transplantation; D002417:Cattle; D003094:Collagen / Q000008:administration & dosage*; D019245:Compressive Strength; D017102:Fracture Healing / Q000187:drug effects; D055428:Growth Differentiation Factor 5; D006133:Growth Substances / Q000008:administration & dosage*; D008159:Lumbar Vertebrae / Q000187:drug effects / Q000601:surgery; D008297:Male; D008422:Materials Testing; D010012:Osteogenesis / Q000187:drug effects*; D011817:Rabbits; D011994:Recombinant Proteins / Q000008:administration & dosage*; D013123:Spinal Fusion / Q000379:methods*
chemical_list: D019485:Bone Morphogenetic Proteins; C525893:GDF5 protein, human; D055428:Growth Differentiation Factor 5; D006133:Growth Substances; D011994:Recombinant Proteins; D003094:Collagen