title: Evaluation of a new formulation of demineralized bone matrix putty in a rabbit posterolateral spinal fusion model.
abstract: BACKGROUND
  Alternatives to autologous bone graft (ABG) with osteoconductive, osteoinductive, and osteogenic potential continue to prove elusive. Demineralized bone matrix (DBM) however, with its osteoconductive and osteoinductive potential remains a viable option to ABG in posterolateral spine fusion.
  
  
  OBJECTIVE
  To compare the efficacy of a new formulation of DBM putty with that of ABG in a rabbit posterolateral spinal fusion model.
  
  
  METHODS
  Efficacy of a new formulation of DBM was studied in an experimental animal posterolateral spinal fusion model.
  
  
  METHODS
  Twenty-four male New Zealand White rabbits underwent bilateral posterolateral spine arthrodesis of the L5-L6 intertransverse processes, using either ABG (control group, n=12) or DBM (DBM made from rabbit bone) putty (test group, n=12). The animals were killed 12 weeks after surgery and the lumbar spines were excised. Fusion success was evaluated by manual palpation, high resolution X-rays, microcomputed tomography imaging, biomechanical four-point bending tests, and histology.
  
  
  RESULTS
  Two animals were lost because of anesthetic related issues. Manual palpation to assess fusion success in the explanted lumbar spines showed no statistical significant difference in successful fusion in 81.8% (9/11) of DBM group and 72.7% (8/11) of ABG group (p=.99). Reliability of these assessments was measured between three independent observers and found near perfect agreement (intraclass correlation cofficient: 0.92 and 0.94, respectively). Fusion using high resolution X-rays was solid in 10 of the DBM group and 9 of the ABG group (p=.59). Biomechanical testing showed no significant difference in stiffness between the control and test groups on flexion, extension, and left lateral and right lateral bends, with p values accounting for .79, .42, .75, and .52, respectively. The bone volume/total volume was greater than 85% in the DBM treated fusion masses. Histologic evaluation revealed endochondral ossification in both groups, but the fusion masses were more mature in the DBM group.
  
  
  CONCLUSIONS
  The DBM putty achieved comparable fusion rates to ABG in the rabbit posterolateral spinal fusion model.
authors: Integrated Spine Research Department, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA. Electronic address: kielyp@hss.edu.
authors: Paul D
authors: PD
authors: Kiely
authors: Integrated Spine Research Department, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors: Antonio T
authors: AT
authors: Brecevich
authors: Integrated Spine Research Department, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors: Fadi
authors: F
authors: Taher
authors: Integrated Spine Research Department, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors: Joseph T
authors: JT
authors: Nguyen
authors: Integrated Spine Research Department, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors: Frank P
authors: FP
authors: Cammisa
authors: Integrated Spine Research Department, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA.
authors: Celeste
authors: C
authors: Abjornson
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000627:therapeutic use*; D001857:Bone Matrix / Q000637:transplantation*; D016025:Bone Transplantation / Q000379:methods*; D001842:Bone and Bones; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D023421:Models, Animal; D010012:Osteogenesis; D011817:Rabbits; D015203:Reproducibility of Results; D013123:Spinal Fusion / Q000379:methods*; D014182:Transplantation, Autologous; D055114:X-Ray Microtomography
chemical_list: D001672:Biocompatible Materials
keywords: Alternative grafts; Autologous bone graft; Demineralized bone matrix; Lumbar spine fusion; New formulation; Rabbit posterolateral spinal fusion model