Allan, activ-l is many years away from approval... they are still enrolling. (Regan did a client of mine in the clinical trial a few weeks ago.) They'll have to wait until ALL enrollees are 2 years post-op to begin packaging the data to submit to the process... my guess is that it will be More than 3 years.
The facet answers are not known. There are competing biomechanical studies that are all interesting exercises, but the results are conflicting. I also believe that some people will benefit more from a stationary core device and others will benefit more from mobile core devices. I don't think that we'll be able to tell who is who in advance... by the time we know, this crop of devices will be obsolete. I don't remember what your films look like, but if your facets are headed south, it may be the case that waiting has already had more impact on the potential outcome than would the choice of prosthesis.
As to your original question... I don't think that the keel has any impact whatsoever on facet issues. Placement... biomechanics (of the device AND your spine) will determine that. Keel is for ease of implantation, resistance to migration, subsidence, and maybe some other issues that I'm not remembering in my very tired state. It comes with advantages and disadvantages. IMHO, it's not one of the more important factors in the decision. (That is based on NOT using a device with a HUGE keel, like the original Maverick... that's a whole other story.)
How 'moderate' are your facets? What have the ADR surgeons said?
Mark
|