In the cervical ADR procedures I've seen, when anterior osteophytes were present, they were 'nipped off' with a tool that looked much like a pair of cobblers pliers. I'm standing next to the doctor asking the same questions you are asking here. The bone wax does seal the 'fresh bone', but will eventually be resorbed. When the bone wax is gone, there are several factors that will reduce or eliminate the risk of the osteophytes reforming.
- The osteophyte formation is the response to a structural problem. The body is trying to fuse the segment. With ADR, the collapsed disc space and structural issues should be resolved.
- The fresh bone is no longer fresh and osteoblast/osteoclast (cells that contribute to bone growth) release should be over
- The anterior longitudinal ligament that is calcified and participating in this bridging effort is gone.
- I'm sure that there are many other contributing factors. Here is the place for the 'I'm not a doctor, just sharing my experiences, yada yada yada."
The posterior osteophytes are a completely separate issue. The process of removing them is quite different because they are not right out in front like the anterior osteophytes. The surgeons are limited with the tools that they can get to the back of the vertebral body through the disc space after the discectomy is complete. It's relatively easy to get the typical osteophytes that form on the dorsal rim of the vertebral body. The bigger they are, the farther they extend down (or up) the vertebral body and it becomes more difficult to reach them. (The tools can't turn a corner to get too far up or down, away from the disc space.) This is why when the osteophytes get too large, the ADR option becomes more difficult or impossible.
I've watched the discussion change a bit over the years and some doctors are able to do more as they gain more experience. I am particularly interested in this because I probably need 2-level cervical disc replacement and I have large posterior osteophytes and am worried about losing the ADR option. I get a cervical MRI at least once a year to keep tabs on this.
I have resurrected an old post that discussed this, plus the need for adequate decompression during ADR surgery on the
Rebound Myelopathy thread.
Mark