This study concerns the safety of bone morphogenetic protein (called BMP) in spinal fusions. BMP is a naturally occurring protein that scientists have discovered can be a replacement for bone grafts. But inappropriate use of this product has resulted in some adverse effects that have only been reported after the fact. Surgeons will want to review this information when thinking about using BMP with their spinal fusion patients.
What constitutes “inappropriate” use of BMP? That is an important point. The manufacturers of this product are clear in how it is to be used. Off-label use (in other words, using it for something other than it was meant for) is one inappropriate use. Another is changing the concentration of the BMP. It is usually applied on a collagen sponge. Squeezing the sponge too much or overfilling the sponge are two ways the implant may be used differently than recommended by the manufacturer.
That might not seem like such a terrible offense but the list of adverse effects suffered by patients as a result of using BMP inappropriately is long. Bone resorption, inflammation, leg pain from radiculitis, breathing problems, infection, swelling and fluid collections, too much bone growth or bone growth into the soft tissues, and blood clots are just a few of the complications reported.
Data is available on both neck and lumbar spinal fusions. Some adverse effects are specific to the location of the fusion. For example, dysphagia (difficulty swallowing) can occur with cervical spine fusions. And retrograde ejaculation has been reported with anterior lumbar spine fusions.
Half of all patients who develop adverse effects from the use of BMP in spinal fusion end up having another (revision) surgery to deal with the problem. Some of the problems encountered are potentially life-threatening, so there is a need to pay close attention to these reports of adverse effects.
But as the author of this study points out, reports of problems and complications after spinal fusion using BMP don’t necessarily mean the BMP was a direct cause of these effects. There are some serious adverse effects from BMP for sure but not all problems can be linked to this device.
More studies are needed to take a closer look at whether these reported events are, in fact, device-related adverse effects. Maybe the patients would have developed these problems as a result of the surgery and they have nothing to do with the use of the BMP. And it would be helpful if researchers could identify risk factors for adverse events associated with the use of BMP in spinal fusion.
Until more is known about the true risks and safety concerns about BMPs, surgeons are advised to be aware of potential problems and discuss them ahead of time with their patients. Using the products according to the manufacturer’s directions may help ensure safe and effective use of BMP. Inappropriate and off-label uses should be avoided until safety issues have been resolved.