A product widely used in spinal surgery may cause male sterility, says a Stanford University study. The conclusion contradicts earlier research by doctors funded by the product’s manufacturer, Medtronic, that found that the product was safe.
Men considering a spinal fusion procedure using Infuse, a bone-growth protein, should be warned about the risk of infertility, the study’s authors said in a news release issued Wednesday by The Spine Journal.
Dr. Eugene J. Carragee, a Stanford medical school professor and the study’s lead author, said the potential infertility side effect of some spinal surgeries long has been known. But the risk of using Infuse “appears to be greater than was originally reported in industry-sponsored publications,” said Carragee, who also edits The Spine Journal.
For some men, the infertility may be permanent, the Stanford study found. The risk is noted in the product’s labeling but is not widely known in the surgical community.
“In my opinion, it is important that men who are considering having children have the opportunity to weigh the risks of the various available procedures,” Carragee said.
Carragee told The New York Times that he decided to research Infuse after receiving a complaint from a Croatian orthopedic surgeon, Dr. Tomislav Smoljanovic.
Smoljanovic has written dozens of letters to medical journals, questioning research by Medtronic-funded doctors who reported no adverse effects with Infuse. He noted that Medtronic-sponsored researchers found that six men in their review had developed a sterility-linked complication but they failed to identify how many of those men had received Infuse as opposed to a bone graft.
Last year, in response to Smoljanovic’s complaints, the Medtronic-supported researchers said that five of the six men who suffered the complication had received Infuse but said there were not enough incidents to link the problem statistically to Infuse, the Times reported. The researchers attributed the problem to surgical technique, not the product.
Two surgeons involved in the original trial that supported Infuse — Dr. J. Kenneth Burkus and Dr. Thomas A. Zdeblick — each have received millions of dollars from Medtronic in consulting fees or royalty payments. They issued statements, however, denying that financial considerations had influenced their findings.
Infuse is used in about half of the 80,000 anterior lumbar fusion procedures performed each year in this country.
Medtronic spokeswoman Marybeth Thorsgaard said the company believed that it had provided the FDA and doctors with all available medical information about Infuse, sales of which reached about $900 million in Medtronic’s most recent fiscal year.
“You have to consider the totality of the data that has been presented, not how one study was reported,” said Thorsgaard.
