title: Evaluation of insoluble bone gelatin as a carrier for enhancement of osteogenic protein-1-induced intertransverse process lumbar fusion in a rabbit model.
abstract: METHODS
  Postero-lateral lumbar fusion in a rabbit model was performed to compare the bone induction potential of autograft, insoluble bone gelatin (ISBG), osteogenic protein-1 (OP-1), and the combination of ISBG and OP-1.
  
  
  OBJECTIVE
  To evaluate the efficiency of ISBG as a carrier/enhancer for OP-1 in a rabbit spinal fusion model.
  
  
  BACKGROUND
  OP-1 or recombinant human BMP-7 has been shown to be effective in inducing new bone formation in surgical applications such as spinal arthrodesis. However, the lack of an ideal carrier contributes to its associated comorbidities (e.g., uncontrolled bone growth, local inflammatory over-response, nonfusion) and limits its use clinically.
  
  
  METHODS
  Adult New Zealand white rabbits (n = 32) underwent bilateral lumbar intertransverse process fusion procedures at L5 to L6 and were randomized to receive: (1) autograft; (2) ISBG; (3) OP-1; or (4) ISBG in combination with OP-1 (ISBG + OP-1). Spinal fusion masses were evaluated by manual palpation, biomechanical testing, radiographic assessment, microcomputer tomography scanning and histologic examination at 6 weeks after surgery.
  
  
  RESULTS
  Treatment of ISBG + OP-1 resulted in higher spinal fusion rates (7 of 7, 100%) than that of autograft (3 of 7, 43%), ISBG (2 of 8, 25%), and OP-1 (2 of 7, 29%) based on manual palpation (P < 0.01). Greater fusion rates in the ISBG + OP-1 group were also evidenced by radiographic examination (P < 0.01), microcomputer tomography bone volume analysis (P < 0.01), and biomechanical testing (P < 0.05). Histologic assessment demonstrated that treatment of ISBG + OP-1 induces new contiguous bone formation in the interval between the transverse processes which was absent in the other groups.
  
  
  CONCLUSIONS
  In this study, ISBG + OP-1 resulted in more effective lumbar intertransverse process fusion than autograft, OP-1 putty or ISBG alone. ISBG is capable of enhancing OP-1-induced bone formation.
authors: Centre for Orthopaedic Research, School of Surgery, University of Western Australia, Western Australia, Australia.
authors: Guanfeng
authors: G
authors: Yao
authors: Yu
authors: Y
authors: Qian
authors: Jimin
authors: J
authors: Chen
authors: Ying
authors: Y
authors: Fan
authors: Karl
authors: K
authors: Stoffel
authors: Felix
authors: F
authors: Yao
authors: Jiake
authors: J
authors: Xu
authors: Ming-Hao
authors: MH
authors: Zheng
mesh_terms: D000818:Animals; D015519:Bone Density / Q000187:drug effects / Q000502:physiology; D055419:Bone Morphogenetic Protein 7 / Q000008:administration & dosage*; D004337:Drug Carriers / Q000008:administration & dosage*; D005780:Gelatin / Q000008:administration & dosage*; D008159:Lumbar Vertebrae / Q000187:drug effects* / Q000502:physiology / Q000601:surgery; D023421:Models, Animal; D010012:Osteogenesis / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D011897:Random Allocation; D016059:Range of Motion, Articular / Q000187:drug effects / Q000502:physiology; D012995:Solubility / Q000187:drug effects; D013123:Spinal Fusion / Q000379:methods*
chemical_list: D055419:Bone Morphogenetic Protein 7; D004337:Drug Carriers; D005780:Gelatin