The local cytokine and growth factor response to recombinant human bone morphogenetic protein-2 (rhBMP-2) after spinal fusion

There is significant variability in the expression of cytokines throughout the fusion process after treatment with rhBMP-2. The inflammatory response appears to peak early (1 and 6 hours), followed by a significant decrease with rhBMP-2 treatment. However, the growth factor expression appears to be suppressed early (1 and 6 hours), followed by a peak at 24 hours, and a second peak at Day 7.