rhBMP-2 (ACS and CRM formulations) overcomes pseudarthrosis in a New Zealand white rabbit posterolateral fusion model.
METHODS
The study design consisted of a New Zealand white rabbit model of pseudarthrosis repair. Study groups consisting of no graft, autograft, or recombinant human bone morphogenetic protein-2 (rhBMP-2) with absorbable collagen sponge (ACS) or compression resistant matrix (CRM) were evaluated.


OBJECTIVE
To evaluate the relative efficacy of bone graft materials (autograft, ACS, and CRM).


BACKGROUND
rhBMP-2 has been shown to have a 100% fusion rate in a primary rabbit fusion model, even in the presence of nicotine, which is known to inhibit fusion.


METHODS
Seventy-two New Zealand white rabbits underwent posterolateral lumbar fusion with iliac crest autograft. To establish pseudarthroses, nicotine was administered to all animals. At 5 weeks, the spines were explored and all pseudarthroses were redecorticated and implanted with no graft, autograft, rhBMP-2/ACS, or rhBMP-2/CRM. At 10 weeks, fusions were assessed by manual palpation and histology.


RESULTS
Eight rabbits (11%) were lost to complications. At 5 weeks, 66 (97%) had pseudarthroses. At 10 weeks, attempted pseudarthrosis repairs were fused in 1 of 16 of no graft rabbits (6%), 5 of 17 autograft rabbits (29%), and 31 of 31 rhBMP-2 rabbits (with ACS or CRM) (100%). Histologic analysis demonstrated more mature bone formation in the rhBMP-2 groups.


CONCLUSIONS
The 2 rhBMP-2 formulations led to significantly higher fusion rates and histologic bone formation than no graft and autograft controls in this pseudarthrosis repair model.
Lawrence
James P
JP
Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, CT 06520-8071, USA.
Waked
Walid
W
Gillon
Thomas J
TJ
White
Andrew P
AP
Spock
Christopher R
CR
Biswas
Debdut
D
Rosenberger
Patricia
P
Troiano
Nancy
N
Albert
Todd J
TJ
Grauer
Jonathan N
JN
D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D018786:Bone Substitutes / Q000737:chemistry; D016025:Bone Transplantation / Q000009:adverse effects; D002626:Chemistry, Pharmaceutical; D004195:Disease Models, Animal; D004337:Drug Carriers; D005260:Female; D006801:Humans; D007085:Ilium / Q000637:transplantation; D008159:Lumbar Vertebrae / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology / Q000601:surgery; D009538:Nicotine; D016348:Osseointegration / Q000187:drug effects*; D011542:Pseudarthrosis / Q000139:chemically induced / Q000188:drug therapy* / Q000503:physiopathology / Q000601:surgery; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D013123:Spinal Fusion / Q000009:adverse effects*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016212:Transforming Growth Factor beta / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D014182:Transplantation, Autologous
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D004337:Drug Carriers; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D009538:Nicotine