CC Four,
The Military will only accept what is 'common practice' accepted by the FDA.
I read once, where a Major in the Marine Corp, had a couple replaced, ADR, with Charite, (in Spain) but there are a number of cases where they are failing or causing complications.
Charite™ Spinal Disc - Charite Disc Complications
{this may be why the US FDA is refusing to approve the M6}
My best recommendation is to go to spain, the UK or Germany, and have a two level M6L.
Look up German Spine Institute, this surgeon, has the best record that I can find, over 1,000 of these, with good to excellent long term outcomes.
If had known how bad my lower back was, (this caused problems on the upper lumbar, to have required surgery and now affecting to lower even more) I would have done the two lower discs a long time ago. (Now looking at a 3 level, L45, L5S1 and the L23)
Go for it, it will cost you about $30K(your two level), but it will be worth it. (this is like dominos, cascading, if you keep the lower two moving, the rest of your spine will stay healthier, this is how the discs get nutrients, by moving)
contact spine solution
Send them your MRI, you can get a copy of the MRI, and use a repository, like DropBox, and upload that file there, up to 2 Gig, and send them the link, easy to register.
Good luck, I am waiting for VA/Insurance approval, if you can appeal the decision by the military, did not deal that much with them when active, but there must be recourse, look for a PA, patient advocate, MMSO or since you are on PT, you may be able to contact the VA, try everything, you CANNOT accept the Fusion, with 14 more years looking at you and your age, this is unacceptable.
Jerry