title: Assessment of Progenix(®) DBM putty bone substitute in a rabbit posterolateral fusion model.
abstract: METHODS
  Randomized, controlled study in a laboratory setting. Blinded observations/assessment of study outcomes.
  
  
  OBJECTIVE
  The purpose of this study is to determine the performance characteristics of Progenix(®) DBM putty as a bone graft extender, enhancer, and substitute in a rabbit posterolateral spine fusion model.
  
  
  BACKGROUND
  The rabbit posterolateral fusion model is an established environment for testing of fusion concepts. It offers the opportunity to obtain radiographic, histological, and biomechanical data on novel fusion materials.
  
  
  METHODS
  Forty rabbits were entered into the study with 37 used for analysis. Bilateral posterolateral lumbar intertransverse fusions were performed at L5-L6. the lateral two thirds of the transverse processes were decorticated and covered with graft material: autograft only (1.5 or 3.0 cc/side), a combination of Progenix(®) (1.5 cc) + autograft (1.5 cc), Progenix(®) (1.5 cc) + autograft (3.0 cc), or Progenix(®) only (3.0 cc/side).
  
  
  RESULTS
  RADIOGRAPHIC FUSION: At 8 weeks the 3.0 cc autograft group had a 67% fusion rate and the 1.5 cc autograft group fused in 25%. the extender group (1.5 cc autograft + 1.5 cc Progenix(®)) had an 88% fusion rate at 8 weeks. In the enhancer group (3.0 cc autograft + 1.5 cc Progenix(®)) 86% of the spines were fused. the substitute group (Progenix(®) only) had a fusion rate of 38%. Manual Palpation: the 3.0 cc autograft group had a 67% fusion rate and the 1.5 cc autograft group fused in 38%. the extender group had an 88% fusion rate. In the enhancer group 86% of the specimens fused. the substitute group had a 50% fusion rate.
  
  
  CONCLUSIONS
  In a rabbit posterolateral fusion model, Progenix(®) DBM Putty in an autograft extender or enhancer mode produced manual palpation and radiographic fusion rates equivalent or slightly better than autograft fusion (3 cc) alone. the results from the two autograft groups demonstrate the need for adequate graft volume to achieve high radiographic and mechanical fusion rates.
authors.affiliation: Department of Orthopaedics and Rehabilitation, The University of Iowa, Iowa City, Iowa 52242, USA. joe@smuckermd.com
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Smucker
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Fredericks
mesh_terms: D000818:Animals; D018786:Bone Substitutes; D016025:Bone Transplantation; D007085:Ilium / Q000637:transplantation*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D023421:Models, Animal; D011817:Rabbits; D011859:Radiography; D013123:Spinal Fusion / Q000379:methods*; D014182:Transplantation, Autologous
chemical_list: D018786:Bone Substitutes