title: A poly(propylene glycol-co-fumaric acid) based bone graft extender for lumbar spinal fusion: in vivo assessment in a rabbit model.
abstract: METHODS
  An animal model of posterolateral intertransverse process lumbar spinal fusion compared fusion rates amongst autologous bone (group 1), a porous, bioabsorbable, scaffold based on the biopolymer, poly(propylene glycol-co-fumaric acid) (PPF) (group 2), and a combination of autograft and the bioabsorbable scaffold (group 3).
  
  
  OBJECTIVE
  To evaluate the feasibility of augmenting spinal fusion with an osteoconductive and bioabsorbable scaffold as an alternative or as an adjunct, i.e., an extender, to autograft.
  
  
  BACKGROUND
  There is little preclinical data on applications of bioabsorable bone graft extenders in spinal fusion.
  
  
  METHODS
  New Zealand White rabbits underwent single-level lumbar posterolateral intertransverse process fusion. Animals were treated with one of three materials: autologous bone (group 1), a bioabsorable material based on PPF (group 2), and the PPF biopolymer scaffold with autologous bone graft (group 3). Animals were evaluated at 6 weeks, and fusion was evaluated by manual palpation, and radiographic, histologic, and histomorphometric analyses.
  
  
  RESULTS
  Radiographic and manual palpation showed evidence of fusion in all three groups. Histomorphometric measurement of bone ingrowth showed the highest quantity of new bone in group 3 (91%), followed by group 1 (72%) and group 2 (53%).
  
  
  CONCLUSIONS
  Results of this study suggested that osteoconductive bioabsorbable scaffolds prepared from PPF might be used as an autograft extender when applied as an adjunct to spinal fusion.
authors.affiliation: Cambridge Scientific Inc., MA, USA. hiledd@yahoo.com
authors.forename: David D
authors.initials: DD
authors.lastname: Hile
authors.forename: Frank
authors.initials: F
authors.lastname: Kandziora
authors.forename: Kai-Uwe
authors.initials: KU
authors.lastname: Lewandrowski
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Doherty
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kowaleski
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Trantolo
mesh_terms: D000818:Animals; D018786:Bone Substitutes / Q000627:therapeutic use*; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000000981:diagnostic imaging / Q000601:surgery*; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011108:Polymers / Q000627:therapeutic use*; D011409:Propylene Glycols / Q000627:therapeutic use*; D011817:Rabbits; D011859:Radiography; D013123:Spinal Fusion / Q000379:methods*
chemical_list: D018786:Bone Substitutes; D011108:Polymers; D011409:Propylene Glycols; C106431:poly(propylene glycol-fumarate)