The Senate report and accompanying documents also show Medtronic employees -- in addition to editing drafts of a paper -- at times covertly drafted responses to questions raised by other doctors who were examining the work as part of medical journal peer review.
Case in point: A 2004 paper was published in the Spine Journal where co-author Dr. Charles Branch Jr. also served as deputy editor. Branch, chairman of neurosurgery at Wake Forest University, received $3.1 million from Medtronic from 1998 to 2010. His royalty payments have been split with the university.
That article also was subject of a 2011 Journal Sentinel/MedPage Today investigation.
The Senate documents include a 2003 email, as the article was being drafted, in which Bill Martin, the company's vice president of spinal marketing, wrote: "We may want to steer clear of calling it a flawed technique. There are still quite a few surgeons utilizing this technique..."
About a week later, Rick Treharne, another Medtronic executive, wrote to one of the paper's authors: "In looking over the data, I was impressed with how well the BMP (Infuse) patients actually did. So much so that I added a few paragraphs at the end that you may not agree with."
As peer reviewers for the journal looked over the paper, they raised concerns that it was a slanted, advertising piece.
"This manuscript is full of biased statements that are a reflection of the data evaluators -- the company that markets the product," wrote one reviewer.
"Unless the authors can discuss the results in this study in an unbiased manner, which they have been unable to do in its present form, this data should not be published," wrote another.
Treharne then sent one of the co-authors a draft of a letter to be sent to the editor of the journal addressing the concern. Another Medtronic executive also helped formulate a response to the editor.
The letter that ultimately was sent to the journal's editor sought to reassure him, claiming that three of the co-authors were independent, the Senate investigation found.
But between 1997 and 2003, two of the "independent" authors had received $8.5 million from Medtronic.
"We were falsely reassured that there were independent people looking at the data," said Dr. Eugene Carragee, who took over as editor of the Spine Journal in 2009. "It's a violation of the fundamental trust of peer review."
When published, the paper described the results of halted clinical trial as "encouraging."