Hello, generally speaking, maple trees are very effective in healing wounds on their own. If there are wounded branches that are ragged, you could prune those off into clean cuts. Without a picture it is hard to provide any more information. If you would like to provide some photos of the wound, I could forward those to one of our extension foresters to see if they have any additional input, but without those and generally speaking, as long as the maple is otherwise healthy and not suffering from any disease, it should be able to heal itself effectively. 

Autumn Ellison, OSU Forestry and Natural Resources Extension