Did a prominent spine surgeon fail to report serious a side effect associated with Medtronic Infuse Bone Graft because of his lucrative relationship with the maker of the bone protein? Investigators with the U.S. Senate Finance Committee appear to think so, after finding “questionable ties” between Medtronic and many of the doctors, including University of Wisconsin surgeon Thomas Zdeblick, who co-authored research that cast a favorable light on Infuse.

Medtronic Infuse Bone Graft is a bone growth protein used in certain spinal fusion surgeries. In July 2011, an investigation published in The Spine Journal raised serious concerns that research used to garner regulatory approval for Infuse was biased, as many of the doctors involved in those studies had significant financial relationships with Medtronic. According to one analysis published by the Journal, more than 13 Infuse clinical trials that were submitted to the U.S. Food & Drug Administration (FDA) prior to its approval failed to report serious complications, including cancer, in patients treated with Infuse. The Spine Journal expose prompted the U.S. Senate Finance Committee to launch its own investigation of Medtronic and Infuse.

In a report released last week, Committee investigators concluded that Medtronic played a major role in “drafting, editing and shaping” medical journal articles about Infuse Bone Graft, all without disclosing roughly $210 million in consulting and other fees over a 14-year period that the company paid to the doctors who co-authored those studies. Zdeblick, who received $34 million in royalties from Medtronic over a 15-year-period, was one of the doctors cited in the Senate Finance Committee’s report.

According to the Wisconsin State Journal, the Senate probe revealed that in a 2001 PowerPoint presentation for doctors working on an Infuse study, Zdeblick reported data that showed 10% of men who received Infuse Bone Graft in laparoscopic procedures developed retrograde ejaculation, a condition that causes sterility. The same presentation revealed that just over 6% who received Infuse in non-laparoscopic surgeries also developed the problem, while only 1.5% of those who received a traditional bone graft suffered from retrograde ejaculation. Yet Zdeblick never reported any of this data in journal articles he co-authored about Infuse. Two of those articles, published in 2002 and 2003, involved input from Medtronic marketing employees, according to Senate investigators.

Zdeblick told the Wisconsin State Journal that the data on retrograde ejaculation was omitted from the journal articles after Medtronic’s analysis determined the risk was tied to the type of surgery performed, not Infuse itself. All of the laparoscopic procedures, and some of the regular surgeries, involved an approach through the abdominal wall. The majority of regular procedures were done done behind the abdominal cavity. Other doctors reported that finding in journal articles published in 2003, according to The Wisconsin State Journal.

But it’s clear from reading the Senate report that investigators believe the financial ties between Zdeblick and other Infuse researcher influenced the way complications were reported in their journal articles.

“Medtronic’s actions violate the trust patients have in their medical care. Medical journal articles should convey an accurate picture of the risks and benefits of drugs and medical devices, but patients are at serious risk when companies distort the facts the way Medtronic has,” Senator Max Baucus (D-Mont.), chair of the Senate Finance Committee, said in a statement announcing the investigation’s findings.

Published November 1, 2012 by