Hunh!
This is really interesting, and I sure would appreciate hearing your reactions.
And in particular, does any one know what the hell a "non-inferiority margin [of 10%/12%]" is?
Check out this link--it appears to be the package insert required by the FDA for the ProDisc, which includes the results of the trials, comparing fusion and ProDisc.
fda.gov/cdrh/pdf5/p050010c.pdf
Two things jump out at me:
On almost every criterion measure, the ProDisc scored quite well. It always scored higher than fusion, and its lowest score was a 67%. (E.g., 85.4% showing 15% or more ODI improvement.) Yet, in the "overall success" category, which differed from the other categories only in the addition of the mystery "non-inferiority margin," ProDisc got rated between 53% and 66.7%. (Fusion scored lower.)
First, does this explain the discrepancy between surgeons/Europeans who claim 75 - 85% success rate, and the official results of the trials: "About 60% success, similar to fusion"?
Second, as noted above, what the hell is "non-inferiority margin"?
Ok, a third thing. The nonrandomized ProDisc group did consistently better on every category than the randomized. I would think the non-randomized were a later group of patients--perhaps outcomes improving with surgeon experience? And you would think any placebo effect would be in the opposite direction, patients in a random trial being happy to have lucked out with the ProDisc.
|