What is a spinal fusion? It simply implies that a segment of the spine is fused and made rigid. There are various ways to do this. The fusion can be done with only bone. The bone may be from a cadaver or your pelvic crest. In either case the bone is packed into the joint regions of the spine to allow the bones to fuse. Most modern fusions include some degree of metal hardware. They may also include bone as well. The metal hardware can be a screw and rod type which looks like an "errector set" or a cage type which is a round cylinder inserted into the space between the bones (where the disc is) and this holds the bones apart. There are other variations such as the plate which is often used in the cervical area. The fusion sometimes leads to increased motion above and below the fusion. this leads to decay of the joints and discs above and below the fusion. As the discs decay they herniate and now a patient may need a repeat surgery to correct the new problem years down the road. this often means extension of the fusion. The success rates for fusions run betwen 50 to 70% good to excellent. That means that up to 70% of people get 50 to 100% relief of their pain.