Any treatments that would repair it? Surgery?
Yes, but a bit tricky (as it applies to Ronnie) and the results are not always absolute. Most Neuro surgeons say, that nerves regenerate (
if they are going to) at a rate of approx one inch per month. In Ronnie's case, it appears the visible damage, the atrophy that has occurred to his triceps and lat, is 14 - 18 inches from his spinal cord. That would of course mean a healing time of 14 - 18 months, IF healing takes place. That differs from person to person, unfortunately.
The healing could only take place if the damaged area was able to be repaired, and even then, nerve regeneration is not always predictable (from what I've heard & read). Plus, after the procedure was done, most likely "anterior cervical disc excission & fusion" he would be instructed not to to "load his spine" aka place vertical pressure on his back, for quit some time, if ever again, at the level he would require to train as a pro bodybuilder.