We can get 'em to regrow in tissue culture but not in a useful "ordering". The key is how the cells get their "order" message, and we still haven't a clue.
Tough nut to crack. It's not so much the cells, but how they're connected. I have seen some promising results in spinal chord regeneration, so perhaps with time and possibly stem cells, something can be done. But I doubt it will be any time in the near future.