Ceramic granules enhanced with B2A peptide for lumbar interbody spine fusion: an experimental study using an instrumented model in sheep.
OBJECTIVE
New generations of devices for spinal interbody fusion are expected to arise from the combined use of bioactive peptides and porous implants. The purpose of this dose-ranging study was to evaluate the fusion characteristics of porous ceramic granules (CGs) coated with the bioactive peptide B2A2-K-NS (B2A) by using a model of instrumented lumbar interbody spinal fusion in sheep.


METHODS
Instrumented spinal arthrodesis was performed in 40 operative sites in 20 adult sheep. In each animal, posterior instrumentation (pedicle screw and rod) and a polyetheretherketone cage were placed in 2 single-level procedures (L2-3 and L4-5). All cages were packed with graft material prior to implantation. The graft materials were prepared by mixing (1:1 vol/vol) CGs with or without a B2A coating and morselized autograft. Ceramic granules were coated with B2A at 50, 100, 300, and 600 microg/ml granules (50-B2A/CG, 100-B2A/CG, 300-B2A/CG, and 600-B2A/CG, respectively), resulting in 4 B2A-coated groups plus a control group (uncoated CGs). Graft material from each of these groups was implanted in 8 operative sites. Four months after arthrodesis, interbody fusion status was assessed with CT, and the interbody site was further evaluated with quantitative histomorphometry.


RESULTS
All B2A/CG groups had higher CT-confirmed interbody fusion rates compared with those in controls (CGs only). Seven of 8 sites were fused in the 50-B2A/CG, 100-B2A/CG, and 300-B2A/CG groups, whereas 5 of 8 sites were fused in the group that had received uncoated CGs. New woven and lamellar bone spanned the fusion sites with excellent osseointegration. There was no heterotopic ossification or other untoward events attributed to the use of B2A/CG in any group. Each B2A/CG treatment produced more new bone than that in the CG group.


CONCLUSIONS
Bioactive treatment with B2A effectively enhanced the fusion capacity of porous CGs. These findings suggest that B2A/CG may well represent a new generation of biomaterials for lumbar interbody fusion and indicate that additional studies are warranted.
Orthopaedic Spinal Research Laboratory, St. Joseph Medical Center, Towson, MD, USA.
Bryan W
BW
Cunningham
Brent L
BL
Atkinson
Nianbin
N
Hu
Jun
J
Kikkawa
Louis
L
Jenis
Joseph
J
Bryant
Paul O
PO
Zamora
Paul C
PC
McAfee
D000818:Animals; D001577:Benzophenones; D001696:Biomechanical Phenomena; D001858:Bone Nails; D001863:Bone Screws; D016025:Bone Transplantation / Q000295:instrumentation / Q000379:methods*; D002516:Ceramics; D020099:Coated Materials, Biocompatible; D015194:Diffusion Chambers, Culture; D005240:Feasibility Studies; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000601:surgery; D007659:Ketones; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D008422:Materials Testing; D023421:Models, Animal; D011092:Polyethylene Glycols; D011108:Polymers; D019736:Prostheses and Implants; D011506:Proteins / Q000494:pharmacology*; D012756:Sheep; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D014057:Tomography, X-Ray Computed; D014182:Transplantation, Autologous
C092654:B2A protein, Ovis aries; D001577:Benzophenones; D020099:Coated Materials, Biocompatible; D007659:Ketones; D011108:Polymers; D011506:Proteins; C063834:polyetheretherketone; D011092:Polyethylene Glycols