storys like this don't give me a good feeling. Strange things can happen. It is very difficult for me to see everything in the road. I have hit small holes in the road no bigger than a golf ball and the surprise of hitting something caused me to swerve. I have also seen box turtles just a few feet in front of me and luckly was able to miss them.
I do understand that it is possible to not know what caused a crash though. About 1 month ago I was practicing doing track stands on my bike and the next thing that I know I am going over the handle bars and the bike is shooting out from under me going in reverse at full speed. I had no forward speed so I just hit the ground and rolled with no injurys. The bike was traveling backwards at 5 to 10 mph and it was not hurt either. I am still scratching my head and trying to decide how this happened. It sort of makes me gunshy and I am more careful as I practice the track stands now.
Good luck with the medical procedures and ride the same road just to show it who's boss.