Medical device maker Medtronic has reportedly been aware of concerns regarding Infuse bone graft procedures during cervical spine surgery for quite a while now. In fact, while the company maintains that its spinal surgery product is still safe, it decided last summer to spend millions of dollars for an independent outlet to review the data from consumer complaints.

And the outcome is split. The company paid $2.5 million for Yale University to review the data regarding spinal fusion using the Medtronic Infuse product, and the college, along with two others, found that there was little improvement between the Medtronic option and other alternatives in spurring bone growth and that many of the studies that initially found signs of success instead had instances of reporting bias.

Infuse bone graft lawyers have cited the results of that study, but also the results of a Senate  committee investigation into the company’s marketing practices released in 2012. The finance committee wrote that Medtronic failed to disclose its involvement in more than a dozen studies that helped to promote the product. In addition, the researchers found that Infuse bone graft came with complications such as male sterility and increased back and leg pain.

Part of the problem, as with many potentially dangerous drugs and medical devices, is what the product is used for by surgeons. The U.S. Food and Drug Administration approved the Infuse bone graft for fusion procedures in the lower lumbar spine, yet some patients received the device for use in the neck. That has led to issues including concerns about swallowing, breathing or speaking. This may be the result of the product being too successful and calcifying unexpected areas.

One of the problems for many patients is that there is such a variety of conditions associated with Infuse bone graft procedures, predominantly based on where it is used. So in addition to the jaw problems noted above and male sterility, there have also been indications of cyst formation, cancer and infection coming from some cervical spine surgeries.

Hundreds of Medtronic Infuse bone graft lawsuits have been filed, alleging that the bone graft device causes dangerous side effects that the company tried to conceal.