What a shame.
When I was managing people, I have paid for a couple of lots of surgery (one back and one knee) because, frankly, the cost of the surgery (in both cases, even the back, they were in and out quickly) was less than the impact of the suffers' absence and impaired performance. I tended to manage busy people (or did I just keep them that way
), so unplanned absences can pinch quite quickly.
It might be worth asking for a fixed cost when you see the surgeon; especially if you are feeling ground down by it all.