ALIF is generally used to treat back or leg pain caused by degenerative disc disease. The surgeon will stabilize the spine by fusing vertebrae together with bone graft material. The procedure is performed through a three- to five-inch incision on the stomach, two common approaches are over the center of the stomach or slightly to the side. The damaged disc is partially removed. Some of the disc wall is left behind to help contain the bone graft material. A metal cage implant filled with bone graft is placed in the empty disc space. This realigns the vertebral bones, lifting pressure from pinched nerve roots. In some patients, this will be enough to secure the vertebrae. For others, the surgeon may need to implant a series of screws and rods along the back of the spine for additional support. Over time, the bone graft will grow through and around the implants, forming a bone bridge that connects the vertebra above and below. This solid bone bridge is called a fusion.