After returning to the Mars station in The Martian, Mark Watney self-operates his wound. How realistic is that self-treatment?
Here is the basic sequence of events, along with screen shots. Please note that some of these are PG-13 graphic, but relevant to the question. If screen shots of realistic injuries are not your thing, please look away.
Mark enters the HAB with a piece of metal sticking out of his abdomen. It did not skewer him all the way through: it appears to have entered an inch or two and to have missed organs that might require "real" surgery to repair.
He removes the metal piece.
He removes his suit, exposing bare skin.
He cleans around the wound.
He appears to apply topical anesthetic in a circle around the wound (note the bloody circles around the wound from the auto-injector he appears to be applying).
He uses surgical tongs to pull out a metal fragment left behind.
Finally, he staples the wound shut.
He also takes painkillers afterward.
When discussing the realism there are a few things to keep in mind:
Mark Watney is a botanist, not a physician. He appears to have received some basic medical training. I would expect on a journey between planets that all astronauts would receive training in a lot of topics where things you take for granted will no longer be available (cannot call an ambulance, for example).
He had to make do with what the situation gave him: his training, available supplies, etc.
Based on what we can assume about Mark's medical training and what tools he used, it appears realistic to me.
The basic idea of "remove obstruction, clean, anesthesia, remove foreign entity, staple shut" is the same general sequence of first aid. Certain types of injuries (e.g. eye wound) might be different, but that is a basic, common sense sequence of events that mirrors my own first aid training that I received in the military.
The tools he used are basic medical tools that I would expect such an expedition to have available. He did not make use of e.g. an MRI machine which I would not expect to be present.
Simple operations on oneself can be difficult due to pain, emotion, etc. but Mark is a trained astronaut: remember at the end when he lectures a class of aspiring astronauts and says, paraphrasing, "you solve one problem at a time, these problems may be very difficult." He did what he had to do (with drugs, of course) because there is nobody else to help him. He is physically and mentally fit and was able to suck it up and put up with the pain because he knew if he did not, he would die.
Visually, it appears realistic. The abdomen has a lot of blood because the blood vessels need to pick up nutrients from the stomach and intestines. Having a bloody wound in that location is very realistic. Aside from that, I was actually quite impressed: that scene did not appear to use much computer graphics and it looked pretty good (gruesome).