So there’s a lot of different things to consider: past/current medications, if you have any long term illnesses, anything that could interact with the anaesthetic or slow down and complicate your healing. Because it’s an elective surgery they want you to be as fit and healthy as possible.
Because MYA don’t operate in hospitals that have every single facility available if something should go wrong, you might find that they won’t operate on you. I, for example, have a blood clotting disorder which, because of the risks involved with that, meant that MYA wouldn’t be able to operate on me. However! That doesn’t mean other companies or places won’t operate- you may just need to look into getting surgery at a venue that’s more like a hospital!
Hope that answers your question xx