There's an AME working in Northern England (Cheshire/Manchester), who should be able to give you a specific answer. He lectures to GP's and nurses "on the circuit," specifically on this subject.
I went to one of his talks a few years ago, and I was surprised to find that the period of time post operatively required prior to flying was quite short. The main risk appeared to involve internal pockets of air expanding as ambient pressure decreases. I can remember Boyles Law, but can't tell you how long you will have to wait !!
If you contact me through a private message, I shall give you his name.