Happy, happy dance! I've just learned that my insurance has approved the claim for the YAG laser surgery last summer. If anyone else needs help submitting the claim after the fact (for pre-approval, you're on your own), let me know. I don't pretend to now be some insurance expert but I would be happy to share the process that worked for me.
No replies expected. Feel free to PM or email me.
Edited to add: my case may have been helped by the fact that portions of my lungs were removed so the surgery wasn't limited to using the YAG laser.