It's a tough problem. For many medical issues gravity is a key element in treatment. One can expect that an instrument or some internal organ will set down when it is released. Fluids tend to head in one direction without prompting. Still, if they can get back readily, that's for the best.
That said, there was a guy in Antarctica who took out their own infected appendix.
"Russian surgeon Leonid Rogozov became seriously ill. He needed an operation - and as the only doctor on the team, he realised he would have to do it himself."
https://www.bbc.com/news/magazine-32481442
He did have a couple of helpers and was motivated by his experience of how things would go if he did not try. It had taken weeks to get to the location and the next ship was one year away. The weather was too bad to allow for an airplane. Dying of peritonitis is far more painful that using a knife.