A cutaneous horn grows from the pad of the toe, the nail grows from just above that. Jack and Pooky both have cutaneous horns and I just trim them when I trim the nails. Doesn't bother them as it has no blood supply or nerve endings. If it's causing pain to the animal it's not a cutaneous horn.

Not knowing if the previous surgery was a single toe declaw and they didn't get all the material out, or if it was just removing the offending part temporarily, it is very possible for a nail to grow back.

It's kinda like having an ingrown toenail surgery done on people, if all the material isn't scraped out, or removed the nail will regrow. I also am familar with that as my dad has had to have 3 toenail surgeries done because his keep growing back. I've only had the one surgery (both big toes) about 1 1/2 years ago and mine still havent grown back. I think it's a difference in doctor experience and dilegence (sp?)

Either way I hope they can find a more permenant solution so Charlie doesn't have any more problems in the future. I hope everything resolves soon.