Thanks everyone for your kind thoughts and advice. I've read some articles on the internet but getting messages from people with their personal experiences is reassuring.
We already have the stair gate but I will certainly get the t-shirt. I have a cone from when she was spayed, but she lost all her spatial awareness when she had it on. The t-shirt sounds much better.
I'm just keeping everthing crossed now that whatever she has is contained in her leg.