Another Infuse Side Effect: Male SterilityMay 26, 2011 | Parker Waichman LLP
Medtronic's Infuse bone graft is the subject of new worries after a study found some men treated with the bone growth product suffered from a condition that could lead to permanent sterility. The author of the study, which is published in The Spine Journal, said in statement that the risk for the side effect - called retrograde ejaculation - appears to be greater than was originally reported by Medtronic-sponsored researchers when Infuse was first approved.
Infuse is made from recombinant human Bone Morphogenetic Protein (rhBMP-2), a protein released naturally by the body. It is approved for treating degenerative Disc Disease and open fractures of the tibia, and for use in certain dental procedures. In the past, it has also been used in cervical spin surgeries, though it is not approved for that use.
According to a press release issued by The Spine Journal, it was always known there is a risk of male infertility with some spine surgeries. The side effect, which causes semen to be misdirected to the bladder, is noted in labeling for Infuse but is not widely known in the surgical community. But this new study suggests the risk may be higher for men who undergo spine surgery with Infuse.
According to a report from The New York Times, the male sterility issue did turn up in a Medtronic-paid study that was published in 2002, right after Infuse was approved. But the researchers conducting the trial attributed the complication to issues with surgical technique. They did not state how many of the men experiencing retrograde ejaculation had received Infuse.
The new study published in The Spine Journal involved a retrospective analysis of 240 men who had interior lumbar interbody fusion, some of whom received Infuse. Of 69 patients who received Infuse, more than 7 percent developed retrograde ejaculation. Of those who did not receive the product, just .06 (1 out of 174) suffered the complication.
“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 so that they can make their best-informed decision," said Eugene J. Carragee, MD, a professor at the Stanford School of Medicine, lead author of the study and editor of The Spine Journal.
In an editorial published in the same issue of the journal, Tommislav Smoljanovich, MD, PhD and Ivan Bojanic, MD, PhD, of the University Hospital Center, Zagreb, Croatia, noted how closely the Stanford findings matched the data from the original Medtronic-sponsored trials that were used to garner U.S. Food & Drug Administration (FDA) approval of Infuse. Those industry-sponsored publications did not report the apparent association of this complication with the product, they write. According to the editorial, the industry-sponsored authors “nonetheless categorically denied any relationship between the rhBMP-2 use and the onset of RE (retrograde ejaculation). In our opinion this categorical denial was not credible.”
A second editorial in The Spine Journal, written by Dr. James D. Kang of the University of Pittsburgh, notes that since its approval, doctors have reported several complications associated with Infuse. These include inflammatory reactions, sterile cyst formation, bone damage, and life-threatening airway complications when used in cervical spine surgery. Dr. Kang also concluded, “there is no convincing data that demonstrates it [Infuse] has significantly improved patient-based outcome measures.”