Many factors come in to play when a doctor is deciding how to proceed with surgery. First, the doctor must evaluate what needs to be done. Certain situations will rule out one type of surgery or the other. If both types are still acceptable, then the surgeon looks at the strength of the spine to see if it would stand up to a fusion or would a replacement be better.
Other issues, such as availability of certain types of implants, the surgeon’s experience with either surgery, as well as recent research reviewing pros and cons of the surgeries, may all come in to play in the decision-making process.