The “cage” does not have to be used if an organic spacer is used (normally an allograft cortical ring).
The BMP and cancer question is one that is being disputed now. There was one paper that noted with a very large dose of BMP (about 10 times the levels used now), there might have been an increase of cancer. However, there are some studies that demonstrate the cancer risk goes down with the use of BMP. I think that both findings are spurious.
I have not seen any increase of rate of cancer in my patients and the generally consensus from other surgeons I have talked to and who use BMP is that these risks are not accurate.
Smoking exposes the body to nicotine. This chemical retards the bone cells (osteoblasts) from migrating and laying down the bony proteins. Without the use of BMP, smoking will prevent fusion in an additional 30% of patients. Smoking is an evil toxin and you need to stop smoking regardless of whether you undergo a fusion or not.
Donald Corenman, MD, DC is a highly-regarded spine surgeon, considered an expert in the area of neck and back pain. Trained as both a Medical Doctor and Doctor of Chiropractic, Dr. Corenman earned academic appointments as Clinical Assistant Professor and Assistant Professor of Orthopaedic Surgery at the University of Colorado Health Sciences Center, and his research on spine surgery and rehabilitation has resulted in the publication of multiple peer-reviewed articles and two books.