Nonunion of anterior cervical fusion are not uncommon. Studies show the rate of nonunion goes up as the number of levels fused together increases. Type of bone graft and surgery may also have an effect on the success or failure of a fusion.
A single-level fusion has a 20 percent chance of failure. A multilevel fusion without the use of plates, screws, or wires to hold it together has a 60 percent chance of nonfusion.
Repeating the fusion from the front is called an anterior revision. It has fewer problems afterwards compared to a posterior fusion to repair the problem. But there's a high rate of failure requiring yet another surgery.
Posterior fusion may be a better option for you. It has a higher success rate and avoids cutting through the scar tissue. Posterior fusion does have more blood loss and postoperative infections. This is because the muscles are stripped off the bone causing more soft-tissue injury. The trade-off is a 98 percent fusion rate.