A study finds that a bone protein used in thousands of spinal fusion surgeries is linked to complications when it is used in the neck and more expensive hospital charges in all categories of spinal fusions. 

This is the first nationwide study of bone-morphogenetic protein, or BMP, which the Food and Drug Administration approved in 2002 for back surgeries but not for spinal fusions in the neck.

The protein instructs cells to turn into bone tissue, but last year the FDA warned of 38 reports of complications when the treatment was used in the neck region of the spine. Complications involved swelling after surgery that caused patients to have difficulty breathing and swallowing.

In the study, which was published in 2009 in the Journal of the American Medical Association, Kevin S. Cahill, MD, PhD, of Brigham and Women’s Hospital in Boston, and his colleagues looked at the records of 328,468 patients who had spinal fusion procedures from 2002 to 2006. They found that use of the protein has increased more than 35-fold in those four years.

They also discovered that when BMP was used in the front of the neck region of the spine, there were complications in 7.09 percent of patients before they left the hospital, compared to 4.68 percent – a 50 percent higher rate – than when the product wasn’t used.

Despite these findings, Dr. Cahill says patients should talk about this study with their surgeons, rather than interpreting it as a reason to not use this protein all together. He says the product has a lot of benefits.

“The advantages of BMP are you don’t have to take bone from the hip and you can prevent pain. But really the main reason people use it is because of the studies on how well it promotes fusion. They are impressive. Some of the early clinical studies show you got fusion in almost 100 percent of patients. So it’s a very potent product and works well to form bone,” he says.

“This is by no means saying it should never be used in the neck. It may help a lot of people if we can find the right dose and prevent re-operations. It’s just that right now there’s not a lot of data on how much to use and what the outcomes are,” he says.

Scientists did not find an increase in complications when BMP was used for fusions in other areas like the lower or upper back or back of the neck. But they did find that hospital charges increased by 11 to 41 percent when the bone growth product was used, regardless of the location of the fusion.

Frank P. Cammisa, Jr., MD, is Chief of the Spinal Surgical Service at The Hospital for Special Surgery in New York City. He says this study is important because it’s the first to look at national patterns of use of BMP. But he says his concern is that the study doesn’t look at long-term complications and doesn’t compare costs over the long term. “Short term obviously the hospital costs are increased,” Dr. Cammisa says. “However, long term, if the use of BMP results in a higher fusion rate, there may be less need for revision surgeries in the future and therefore it would be a bottom line decrease in cost; as a result we need more longitudinal data to determine its cost effectiveness.”

Dr. Cammisa says in the future it would be nice to see a study of dosing, so surgeons have a better idea of how much is necessary to increase the fusion rate, while decreasing the complications rate. And he agrees with Dr. Cahill that it would be nice to get more specific guidelines for its use while also looking at long-term risks and benefits.

“Clearly there are benefits to this product. It’s a very useful product. It’s just that we don’t really know who really needs this product. A lot of people will heal from fusions on their own. We need to develop guidelines for who should use the product and who shouldn’t,” Dr. Cahill says.