What are possible complications from surgery with BPM?

I have had chronic fatigue for months now, especially after having back surgery in July 2008. I had bone morphogenic protein placed in my back and since then have suffered with severe itching and rashes that come and go along with the fatigue. My blood work took some time to return to normal after the surgery. The only thing that has been good about this is that I healed much faster than with my previous back surgery. Have you heard of anyone having complications after a surgery with BMP? Thank you for your help.