Bone morphogentic protein, called BMP, is a naturally occurring protein that scientists have discovered can be a replacement for bone grafts. A bone graft is a procedure where a surgeon replaces part of a bone to attach to another bone to either replace a missing part or to strengthen it. Usually, the graft is done with part of the patient’s bone, taken from elsewhere in the body, but grafts can be taken from cadavers, people who have donated their body for this purpose.
At issue with BMP is the lack of studied done regarding the safety of using it among children. Currently, there are good safety reports for adult use.
The product, rhBMP, has been used in children on an off-label basis, meaning it has not been given the official go-ahead by the United States FDA. Good reports have come from its use such as with one case where rhBMP was used to correct problems with the tibia in three different children. It was also used successfully for spinal surgery in a 2-year-old girl. On the other hand, one study, done by Lee and colleagues, found that of five cases where they used rhBMP for tibia correction, only one had a satisfactory response. The authors of this article evaluated the use of the product recombinant human bone morphogenetic protein , or rhBMP, in children to see if there were any complications that could be associated with its use.
Researchers found 81 patients (37 male) who had 101 surgical procedures using rhBMP among them. The children ranged in age from 1.6 years to 17.8 years at the time of their surgery or surgeries. The researchers reviewed the patients’ charts for demographic information, surgical records, and follow-up data. Follow-up lasted, on average, about 22 months. In addition, the researchers searched through the medical literature to find mentions of any types of complications and theoretical complications associated with the use of rhBMP.
The researchers were able to find nine operative site problems that included abnormal wound drainage (five patients), swelling (two patients), and dehiscence (wound opening) (two patients). These all resolved with local wound care. Seven problems that could have been related to the use of rhBMP were also noted. This left the group with a complication rate of 17.5 percent. Because of multiple surgeries in some children, some were exposed to rhBMP more than once: eight received it twice and one patient three times. There were three complications noted in this smaller group, leaving a 27 percent rate. No signs of toxicity in the system were found by the researchers, nor was their excessive bone growth at the grafting location.
Other complications included infections, which may occur after any type of surgery. In this study, three patients had deep infections when they were seen at follow-up and this needed care, including irrigating (cleaning out) the wound, debriding (removing dead tissue) and intravenous antibiotics. Another possible post-surgery problem is compartment syndrome, a condition where the nerves, blood vessels, and muscle become compressed. One patient in this study did develop post-surgical compartment syndrome. Another patient developed dural fibrosis, a thickening of tissue, which resulted in weakness.
One concern was the possible carcinogenicity, or cancer causing issues with rhBMP. The researchers did not find any cancers of the soft tissues, called sarcoma, although one patient was diagnosed with cancer in the brain (gliomas).
In conclusion, the authors believe that their study findings show that rhBMP is a relatively safe product to be used in children when it is appropriate. However, because it is still being used off-list, the use of the product should be thoroughly discussed with the parents or guardians before it is used in the children.