There are always some risks with any operation. Fusion of the neck has its own set of risks because of the potential for spinal cord or nerve damage. The worst thing that could happen is death or paralysis.
Other serious problems include blood clots, heart attack, stroke, or major blood loss. There can also be damage to the trachea, esophagus, or vocal cords. If bone is used from your hip to complete the fusion, there can be a painful or tender area where the bone is removed.
Overall, the chances of having a serious problem after this operation are fairly low.
The risk of fusion failure increases with multi-level fusions. This is a separate problem than those caused by the actual surgery. Various studies report 80 to 90 percent good or excellent results with neck fusion.