There was a study done recently that may help answer your question. The study was done because of an observation that was made about patients who have a cervical spine fusion procedure when those patients are part of a Food and Drug Administration (FDA) study. They have a higher reoperation rate compared with people who have a cervical fusion outside of an FDA study.
To be more specific, the cervical fusion patients in this study received the standard anterior cervical discectomy and fusion (ACDF) procedure. Two groups of fusion patients were compared. One group was part of the FDA investigational studies comparing results of ACDF (the control group) with disc replacement. The second group were patients who had the same ACDF procedure as part of their regular clinical treatment (not as a control group or experimental group).
It is suspected that just being part of an investigational study comparing disc replacement to cervical fusion was enough to produce the difference in results. In other words, being a patient in an FDA study is a risk factor for a second surgery.
But there may be a simpler explanation than that. It’s possible that the way a fusion was defined as “failed” is the real problem. Not every surgeon, researcher, or investigator who conducted the various studies used the same criteria to describe what was (or wasn’t) a failed result.
Finding a way to describe a “failed” first fusion procedure that could be used in all studies would be very helpful. If each surgeon identifies what he or she views as a “failure” but it’s not routinely the same from study to study, then the results measured in terms of reoperation rates isn’t possible. Studies are needed to establish “thresholds” for reoperation (i.e., at what point would reoperation always be recommended no matter what study the person is in)?