A warning was issued recently by the U.S. Food and Drug Administration to doctors informing them not to use Medtronic’s Infuse bone graft product in surgery on neck bones, which is considered an off-label practice the agency never approved. The Infuse powder is FDA approved for use in fusion surgeries such as in the lower back, some serious leg fractures and some oral and dental uses. The product is a genetically engineered protein that causes the body to grow its own bone. The warning issued this week also covers OP-1 brand bone graft products from Kalamazoo, Mich.-based Stryker Corp. The FDA’s warning is stating that for unknown reasons using these products in the neck can cause dangerous complications. The FDA has received at least 38 reports of complications in the past four years related to use of Infuse and OB-1 in neck fusion surgeries. The neck and throat tissue of some patients swelled, the agency said. Some patients had difficulty swallowing, breathing or speaking. Some required a second surgery to resolve the issue, and in some cases, health-care workers inserted tubes to keep them breathing, the FDA said.