Osteogenic protein-1 overcomes the inhibitory effect of nicotine on posterolateral lumbar fusion.
METHODS
An established rabbit posterolateral lumbar fusion model was used to evaluate the ability of osteogenic protein-1 to overcome the inhibitory effect of nicotine.


OBJECTIVE
To determine whether osteogenic protein-1 should be considered as a bone graft alternative for the patient who smokes.


BACKGROUND
Smoking interferes with the success of posterolateral lumbar fusion. This inhibitory effect has been attributed to nicotine and confirmed in a New Zealand white rabbit model. Osteoinductive protein-1 has been shown to induce posterolateral spine fusion reliably in the rabbit model. The effectiveness with which osteogenic protein-1 induces fusion in the presence of nicotine has not been studied previously.


METHODS
Single-level posterolateral intertransverse process fusions were performed at L5-L6 in 18 New Zealand white rabbits. Either autograft or osteogenic protein-1 was used as grafting material. Nicotine was administered via subcutaneous mini-osmotic pumps. The animals were killed 5 weeks after surgery, and the resulting fusion masses were studied.


RESULTS
Three rabbits (17%) were excluded because of complications. By manual palpation, two of the eight nicotine-exposed autograft rabbits (25%) and all of the nicotine-exposed osteogenic protein-1 rabbits (100%) were found to be fused. These results correlated well with those obtained from biomechanical testing. Histologically, the fusion zones of the nicotine-exposed autograft rabbits were distinctly less mature than the fusion masses of the nicotine-exposed osteogenic protein-1 rabbits.


CONCLUSIONS
Osteoinductive protein-1 was able to overcome the inhibitory effects of nicotine in a rabbit posterolateral spine fusion model, and to induce bony fusion reliably at 5 weeks.
Patel
T C
TC
Department of Orthopaedics and Rehabilitation, Yale University School of Medicine, New Haven, Connecticut 06520-8071, USA.
Erulkar
J S
JS
Grauer
J N
JN
Troiano
N W
NW
Panjabi
M M
MM
Friedlaender
G E
GE
D000818:Animals; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D016025:Bone Transplantation; D003367:Cotinine / Q000097:blood; D006085:Graft Survival / Q000187:drug effects*; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000473:pathology / Q000601:surgery; D023421:Models, Animal; D009538:Nicotine / Q000009:adverse effects* / Q000097:blood; D011817:Rabbits; D011859:Radiography; D013123:Spinal Fusion; D016212:Transforming Growth Factor beta
D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D016212:Transforming Growth Factor beta; D009538:Nicotine; D003367:Cotinine