title: Biological performance of a polycaprolactone-based scaffold plus recombinant human morphogenetic protein-2 (rhBMP-2) in an ovine thoracic interbody fusion model.
abstract: OBJECTIVE
  We develop a sheep thoracic spine interbody fusion model to study the suitability of polycaprolactone-based scaffold and recombinant human bone morphogenetic protein-2 (rhBMP-2) as a bone graft substitute within the thoracic spine. The surgical approach is a mini-open thoracotomy with relevance to minimally invasive deformity correction surgery for adolescent idiopathic scoliosis. To date there are no studies examining the use of this biodegradable implant in combination with biologics in a sheep thoracic spine model.
  
  
  METHODS
  In the present study, six sheep underwent a 3-level (T6/7, T8/9 and T10/11) discectomy with randomly allocated implantation of a different graft substitute at each of the three levels: (a) calcium phosphate (CaP) coated polycaprolactone-based scaffold plus 0.54 μg rhBMP-2 (b) CaP-coated PCL-based scaffold alone or (c) autograft (mulched rib head). Fusion was assessed at 6 months post-surgery.
  
  
  RESULTS
  Computed Tomographic scanning demonstrated higher fusion grades in the rhBMP-2 plus PCL-based scaffold group in comparison with either PCL-based scaffold alone or autograft. These results were supported by histological evaluations of the respective groups. Biomechanical testing revealed significantly higher stiffness for the rhBMP-2 plus PCL-based scaffold group in all loading directions in comparison with the other two groups.
  
  
  CONCLUSIONS
  The results of this study demonstrate that rhBMP-2 plus PCL-based scaffold is a viable bone graft substitute, providing an optimal environment for thoracic interbody spinal fusion in a large animal model.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, 60, Musk Avenue, Kelvin Grove, Brisbane, QLD, 4059, Australia, mosy@hotmail.com.
authors.forename: Mostyn R N O
authors.initials: MR
authors.lastname: Yong
authors.forename: Siamak
authors.initials: S
authors.lastname: Saifzadeh
authors.forename: Mia
authors.initials: M
authors.lastname: Woodruff
authors.forename: Geoffrey N
authors.initials: GN
authors.lastname: Askin
authors.forename: Robert D
authors.initials: RD
authors.lastname: Labrom
authors.forename: Dietmar W
authors.initials: DW
authors.lastname: Hutmacher
authors.forename: Clayton J
authors.initials: CJ
authors.lastname: Adam
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage*; D018786:Bone Substitutes / Q000008:administration & dosage* / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D017586:Diskectomy / Q000379:methods*; D006801:Humans; D008297:Male; D011091:Polyesters / Q000737:chemistry*; D011994:Recombinant Proteins / Q000008:administration & dosage; D012600:Scoliosis / Q000473:pathology / Q000601:surgery; D012756:Sheep; D013123:Spinal Fusion / Q000379:methods; D013904:Thoracic Vertebrae / Q000601:surgery; D054457:Tissue Scaffolds / Q000737:chemistry; D016212:Transforming Growth Factor beta / Q000008:administration & dosage*; D014182:Transplantation, Autologous
chemical_list: D055396:Bone Morphogenetic Protein 2; D018786:Bone Substitutes; D002130:Calcium Phosphates; D011091:Polyesters; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; C016240:polycaprolactone; C020243:calcium phosphate