We use a dremmel tool with a sanding disc.
Only do a little at a time...to get the dog used to the process. If you do it every three or four days you can get the nerve to recede and then the dog will not feel the sanding disc.
Aero still will try to pull one of his feet away that is very sensitive but he now lets us use the dremmel on him every few days and it only takes about two minutes. We have his nails to the point that if we hear his nails on the our hardwood floors they are too long...a little each time is all that is needed to keep them appropriately trimmed.
Takes a little human discipline...and a little training but it is well worth the effort.