Medtronic Inc. has settled an Infuse Bone Graft System lawsuit for $22 million over allegations that the device can cause serious health complications and related accusations, and the medical device company has set aside even more money to settle future lawsuits.

Medtronic is the manufacturer of the Infuse System. Infuse is a bone graft system designed for certain type of spinal surgeries. Specifically, the device is used for spinal fusions, a surgery where two adjacent backbones are joined together. This procedure is intended to treat degenerative disc disease. In some individuals, the discs of support tissue between the vertebrae degrade with age, causing pain and even spinal damage. Spinal fusion joins individual vertebrae together into a single bone in order to work around the damaged disc and provide stability for the spine.

The Infuse System has two parts: a metal cage and a bioengineered gel. The metal cage supports the bones of the spine as they fuse, and adds additional support once the new bone grows. The bioengineered gel contains tissue from the patient’s body that encourages new bone growth. This was intended to be an advantage over older spinal fusion procedures, which required a second surgery to harvest bone material from elsewhere in the body. However, Infuse bone graft lawsuits have alleged that the device can cause serious complications.

The Infuse lawsuits against Medtronic have alleged that the device can encourage abnormal bone growth, which can damage nerves and other tissue in the spinal column. This can lead to pain, paralysis and numbness. Several independent reviews found that Medtronic actively promoted the device for unapproved surgeries, and actively overstated the benefits of Infuse.

In 2012, Medtronic agreed to their first out-of-court settlement related to the Infuse System. This amounted to an $85 million settlement, but was awarded to the company’s investors over allegations that the company’s promotion of the device for off-label procedures amounted to illegally inflating their stock.

However, the latest round of settlements involves patients who allegedly experienced complications. In these Infuse bone graft lawsuits, Medtronic has already agreed to $22 million to settle existing lawsuits and states that it faces 3,800 similar bone graft lawsuits, which could amount to $120 million to $140 million in settlements.

The Infuse lawsuits against Medtronic may take the form of a group lawsuit like a multidistrict litigation (MDL) or class action lawsuit. Group lawsuits like MDLs and class action lawsuits allow a group of plaintiffs to seek civil relief over similar alleged harms against the same defendant. The main difference between class action lawsuits and MDLs is that class action lawsuits start out as group lawsuits, while MDLs start as individual lawsuits which are later consolidated into a single legal action. This makes MDLs more common for drug lawsuits than class action lawsuits, since injuries are not uniform but tend to vary.