Medtronic sales are up despite a growing number of lawsuits over Infuse complications.

Beating Wall Street expectations and competing spinal devices, Medtronic Inc.’s Infuse second quarter’s sales topped $745 million, all while lawsuits for off-label use of the product continue to be filed. Medtronic Infuse side effects and complications have been alleged by numerous bone graft recipients.

Competitors Core Spine and Interventional Spine, which use their company’s “balloon kyphoplasty product line,” declined in market share, but the overall market for spinal devices is still going strong.

Medtronic Infuse relies on bone morphogenetic proteins (BMPs). More specifically, it relies on a specific gene from bone and tissue (rhBMP-2) to create genetically engineered cells. These cells, in turn, produce large quantities of rhBMP-2. This is the liquid bone protein now known as Infuse.

The U.S. Food and Drug Administration (FDA) approved the Medtronic Infuse Bone Graft System for limited use during spinal fusion procedures for spinal repair. It was only approved as a full system, with all parts used, in frontal approach lumbar spine surgery. Any other use is constituted as “off-label.”

It’s estimated that as much as 90 percent of the Infuse bone grafts were implanted in spinal surgery patients for uses not listed on the label. This is at the heart of most individual and Medtronic class action lawsuits.

While the Infuse product is meant to aid fusion between the vertebrae, when not used properly, the side effect can create unwanted bone growth. But the off-label use makes up the largest part of Medtronic’s market share, as it sells the Infuse BMP separately.

The growth of Medtronic’s Infuse sales is surprising not only to Wall Street, but to patients who suffered Infuse injuries.

In 2006 and 2007, the journals Spine and The Spine Journal (a publication of the North American Spine Society publication) released articles detailing the risks from off-label use of Infuse in cervical spine fusions compared to traditional fusion surgeries.

In 2011, they brought to light Medtronic’s allegedly corrupt marketing practices. It was discovered that Medtronic paid physicians thousands to millions of dollars to be “Key Opinion Leaders,” publishing studies and medical journal articles downplaying or concealing the risks of adverse events from off-label use while at the same time directly advocating such use of Infuse via presentations to other spine surgeons.

Risks that the publication felt were underplayed included male sterility and cancer, in addition to more traditional risks that would necessitate revision surgery like chronic radiculitis, displacement or migration of the spacer cage, and pseudoarthrosis.

According to an article published in November in MDDI Online, “Medtronic’s CEO, Omar Ishrak, sought to defuse the controversy and took an unprecedented step by providing the clinical data that led to the product’s FDA approval to Yale researchers and gave them a $2.5 million grant to independently review it.”