A posterior spinal fusion is a procedure in which two or more spinal vertebrae are fused together, usually with a combination of bone taken from the hip and metal instrumentation such as hooks, rods, or screws. The bone taken from the hip is known as a bone graft. Some newer procedures are able to use synthetic material to simulate the bone, rather than needing to make an additional hip incision. In a posterior spinal fusion, the surgeon will access the spine through the back, which is the most common procedure. For more complex procedures, surgeons might do an anterior spinal fusion, accessing the spine from the abdomen and side, as well as the back.
There are many different reasons a surgeon might perform a posterior spinal fusion. Put simply, the procedure prevents any further movement between the spinal vertebrae that are fused, ideally eliminating pain, if the pain is caused by that movement. It is often performed after spinal fractures, to treat disk degeneration, or to treat and correct congenital conditions such as severe scoliosis and kyphosis, among other reasons. The bone graft will grow between the two or more vertebrae, fusing them together into one, and preventing any further movement.
Once the bone graft has been added to the spine, it is necessary for the surgeon to immobilize the area while the bone grows, which can take a few months. For this reason, hardware is often installed in the spine as well. This can include steel or titanium rods on each side of the spine to hold it in place, as well as hooks and screws to prevent the rods from moving. The patient will not be able to feel these items, but they will decrease flexibility depending on the location of the fusion, such as if it is in the lumbar or thoracic spine.
Some surgeons will not require their patients to wear a back brace after a posterior spinal fusion, but many will. The size of the brace also depends on the location of the fusion, but patients should expect to have to wear it for a few months, usually for 24 hours per day. It is very important that the posterior spinal fusion heals properly, otherwise the surgeon may need to repeat the entire procedure. Though complications are a risk with any surgery, spinal procedures can be especially dangerous, so it is important to understand all the risks, and the realistic outcome before agreeing to it.