Spinal fusion is a surgical procedure that joins two or more vertebrae. When the spine has been deformed due to disease, weakened by infection or tumor, or if you are suffering from a pinched or injured nerve, this procedure is performed to straighten the spine and to reduce or prevent pain. This surgery is also performed to remove any excess bone or tissue that are narrowing the spinal canal and squeezing the spinal cord. The concept is to fuse together the vertebrae that are causing pain so that they heal together into a single, solid bone. Metal implants are generally used to hold the vertebrae together until new bone grows between them.