Mainstay Medical International plc, together with its subsidiaries, operates as a medical device company in Ireland, the United States, Australia, Germany, and the Netherlands. It focuses on commercializing ReActiv8, an implantable restorative neurostimulation system to treat people with disabling chronic low back pain. The company was formerly known as Mainstay Medical plc and changed its name to Mainstay Medical International plc in March 2014. Mainstay Medical International plc was founded in 2008 and is headquartered in Dublin, Ireland.