Was this real, or just made up for the internet?
My first question was if the laser was properly grounded, so it wouldn't cause sparks. I have heard of cautery fires from the alcohol used to clean the skin area, or (in the good old days) from ether explosions.
In the good old days, we wore special "surgical shoes" that had a metal spike in the sole of the shoe... the inside of the shoe was constructed to collect static electricity from the body (from your clothing rubbing on itself when you walked)... in those days, the surgical gowns were all cotton cloth.
Later, plastic disposable shoe covers were used, with a strip that went across the bottom of the shoe and then went into a ribbon that you put inside your shoe. This was a big help, since it was often hard to clean all the blood off of the leather shoes, and although this was before the days of HIV, blood was a protein that could grow germs so it was an infectious hazard.
They also switched to disposable gowns and hats about that time (1970).
I have no practice with lasers, but Improbable research has a report on an experiment to check if the story could be true.
read the whole thing...
and check out their videos.
one tiny error in the experiment: Smoke is particulate matter, so has a different dispersal pattern than gases. (i.e. the methane and hydrogen sulfite gases in farts).
They also equated the slow emission of smoke from a tube as the same as the (usually fast) emission of gas that would have taken place in this scenerio. However, since methane is lighter than air, the possibility that it went upward into the surgical field is quite probable.