The efficacy of different commercially available demineralized bone matrix substances in an athymic rat model.
OBJECTIVE
Bone graft substitutes have been developed because there is a limited supply of autogenous graft and the harvesting of iliac crest bone graft is associated with significant morbidity. Currently, there are a number of different commercially available demineralized bone matrix (DBM) products available that have been prepared by different methods and have different carriers. The objective of this study was to compare eight different commercially available DBM products.


METHODS
Eight different DBMs were used to attempt a spinal fusion between the L4-L5 transverse processes in athymic rats. There were 10 rats in each group, and 5 rats were killed at both 4 and 8 weeks. Radiographic and histologic analyses were performed. Manual palpation testing was also performed.


RESULTS
At 4 weeks, Osteofil Paste had the highest radiographic scores, whereas Grafton Putty had the best radiographic scores at 8 weeks. Conversely, the spines implanted with Allomatrix had the lowest radiographic scores at both 4 and 8 weeks. In regard to forming a spinal fusion confirmed by manual palpation, Osteofil Paste was the most effective at 4 weeks, whereas Grafton Flex and Grafton Putty had the highest rate of fusion at 8 weeks. Conversely, the lowest rates of fusion were seen in the Allomatrix and Grafton Crunch groups. Statistical analysis showed that there were significant differences among the groups seen on radiographs and by manual palpation. Qualitative differences could be appreciated between the groups histologically.


CONCLUSIONS
Significant differences exist among commercially available DBMs in forming a spinal fusion in an athymic rat.
Lee
Yu-Po
YP
Department of Orthopaedic Surgery, University of California at Los Angeles, Los Angeles, CA 90095-7036, USA.
Jo
Mark
M
Luna
Mario
M
Chien
Bobby
B
Lieberman
Jay R
JR
Wang
Jeffrey C
JC
D000818:Animals; D001857:Bone Matrix; D018786:Bone Substitutes; D005260:Female; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D023421:Models, Animal; D016348:Osseointegration; D011859:Radiography; D051381:Rats; D011923:Rats, Nude; D013123:Spinal Fusion / Q000379:methods*
D018786:Bone Substitutes